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3[[quoteright:330:https://static.tvtropes.org/pmwiki/pub/images/ctenochasma_elegans_1.jpg]]
4 [[caption-width-right:330:Pterosaur[[note]]''Ctenochasma elegans''[[/note]] fossil]]
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6[[foldercontrol]]
7
8!If you're looking for:
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11
12'''Pterosaurs:'''
13
14[[folder:Pterodactyloids]]
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18'''Master of the Air:''' ''[[http://en.wikipedia.org/wiki/Geosternbergia Geosternbergia]]'' (or ''Pteranodon sternbergi'')
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20* ''Geosternbergia'' (or ''Pteranodon sternbergi'', depending on who you ask) lived in the coastlines of Late Cretaceous North America, just like its pop culture relative, ''[[UsefulNotes/StockDinosaursNonDinosaurs Pteranodon longiceps]]'', with which it is sometimes confused. Slightly larger than the latter, its name is a reference to early XX century palaeontologist Charles Sternberg. It also had a more striking look: its beak was curved upwards, and its crest was taller, shorter and more developed. Like ''P. longiceps'', this pterosaur had also females with a small stubby headcrest, for uncertain reasons. ''Geosternbergia'' was briefly portrayed in Disney's ''WesternAnimation/{{Dinosaur}}'': perhaps the ''only'' mostly correct pterosaur portrait ever made in fiction.
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24'''The Fingerless:''' ''[[http://en.wikipedia.org/wiki/Nyctosaurus Nyctosaurus]]''
25
26* Another pterosaur from the same habitat, ''Nyctosaurus'' ("night lizard"), was also similar to ''Pteranodon longiceps'' but smaller and straight-beaked, and had an extraordinary, ''two-branched'' crest. The two branches may have supported a flap of skin, though this is unlikely, and there is no evidence to support it. This was also the only pterosaur ''without non-wing fingers'' on each hand, making it the most aerial reptile ever discovered. ''Nyctosaurus'' appears in the Walking With spin-off ''Series/PrehistoricPark''.
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30'''The Giraffe-Storks:''' ''[[http://en.wikipedia.org/wiki/Azhdarcho Azhdarcho]]'' and its relatives
31
32* Azhdarchids were the only confirmed pterosaur family still alive at the end of the Cretaceous [[note]]accumulating evidence is present to suggest that many other pterosaurs also made to the end; such as nyctosaurs, but currently remains of non-azhdarchid pterosaurs are sparse[[/note]] when it was hit by the K-Pg extinction event. The largest pterosaurs known to science (''[[UsefulNotes/StockDinosaursNonDinosaurs Quetzalcoatlus]]'' and ''[[UsefulNotes/StockDinosaursNonDinosaurs Hatzegopteryx]]'') belong to this family, but there were also many other smaller-sized cosmopolitan members as well (like the Asian namesake ''Azhdarcho''). Their heads were vaguely ''Pteranodon''-like with toothless mouths, but they had small crests (if they had crests at all) and, in some cases at least, very long beaks. They were among the less aerial pterosaurs, with relatively short wings and very long neck and hindlimbs; now ptero-scientists think they were rather stork-like in habits, walking around, grabbing any animal they could swallow and eating them. ''Hatzegopteryx'' is an exception, as its much more robust body plan made it a big-game hunter. ''[[http://en.wikipedia.org/wiki/Alanqa Alanqa]]'', from mid-Cretaceous Morocco, may also be an exception, as that species has a specialized beak that could imply durophagy (feeding on hard-shelled organisms).
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36'''Winged Nutcracker:''' ''[[http://en.wikipedia.org/wiki/Dsungaripterus Dsungaripterus]]''
37
38* ''Dsungaripterus'' ("wing from Junggar") lived in Early Cretaceous Asia. Smaller than ''Pteranodon'' but larger than ''[[UsefulNotes/StockDinosaursNonDinosaurs Rhamphorhynchus]]'', it's easily recognizable thanks to its robust and unusually-shaped skull - the toothless beak curves upwards, robust teeth are present further back in the jaw, and a sinusoidal crest is present on the top of the head. The sturdy build of the jaws indicates a diet of hard objects; traditionally believed to be a shellfish specialist, it's also been proposed to have crushed bone. Similar but earlier and more primitive than ''Dsungaripterus'' was ''[[http://en.wikipedia.org/wiki/Germanodactylus Germanodactylus]]'' from Late Jurassic [[ExactlyWhatItSaysOnTheTin Germany]]: this one lived alongside two of the most famous flying reptiles, ''Pterodactylus'' and ''Rhamphorhynchus'', and also the true dinosaurs ''Archaeopteryx'' and ''Compsognathus''.
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42'''Flying Duckbill:''' ''[[http://en.wikipedia.org/wiki/Istiodactylus Istiodactylus]]''
43
44* ''Istiodactylus'' was once called ''[[ScienceMarchesOn Ornithodesmus]]'', although that name turned out to be from a [[UsefulNotes/PrehistoricLifeBirdlikeTheropods dromaeosaurid]]. It was a fairly large European pterosaur from the Early Cretaceous, flying above ''Iguanodon'' and other dinosaurs from the same fauna. It was characterized by a spatula-like bill similar to the modern bird called [[http://en.wikipedia.org/wiki/Spoonbill spoonbill]], but lined with small teeth. It might have been a scavenger, as the teeth are serrated and tightly-interlocking, unlike the long, conical teeth of piscivorous pterosaurs. Indeed, the several pterosaurs from the Cretaceous had very diverse head shapes and different food habits, just like modern birds.
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48'''A Whale of a Pterosaur:''' ''[[http://en.wikipedia.org/wiki/Pterodaustro Pterodaustro]]''
49
50* ''Pterodaustro'' was perhaps the most specialized of all pterosaurs. Its name means "southern wing": it was the first discovered among the numerous South American pterosaurs. It is often seen as a sort of Cretaceous flamingo, and for good reason: its lower jaw was filled with hundreds of long, narrow, baleen-like teeth - probably used to filter microscopic plankton out of the water in a similar manner. Its upper jaw had many tiny teeth as well. Unlike flamingos, the jaws were curved ''upwards''. Thanks to all this, the pterodaustro could even be considered as a [[SpaceWhale flying version of baleen whales]]. ''Pterodaustro'' is a Ctenochasmatid, closely related to other filter-feeding but less specialized pterosaurs, such as the Late Jurassic European ''[[http://en.wikipedia.org/wiki/Ctenochasma Ctenochasma]]'' ("comb jaw"), whose species ''C. elegans'' was once put in the genus ''Pterodactylus''; ''[[http://en.wikipedia.org/wiki/Gnathosaurus Gnathosaurus]]'' ("jaw lizard"), with crammed teeth on the tip of its jaws; and ''[[http://en.wikipedia.org/wiki/Cycnorhamphus Cycnorhamphus]]'' ("swan beak"), once named "Gallodactylus" ("rooster-finger"). Other members of the group include the Chinese ''Moganopterus'' and ''Gegepterus''.
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54'''The Biggest? Or Not?:''' ''[[http://en.wikipedia.org/wiki/Tropeognathus Tropeognathus]]''
55
56* ''[[http://en.wikipedia.org/wiki/Ornithocheirus Ornithocheirus]]'' ("bird with hands", once also known as "Criorhynchus", "keeled beak") was one of the first pterosaurs discovered, being named in 1869 for a fragmentary snout tip from early Cretaceous England. Since then, it's been involved in massive taxonomic quagmire, with dozens of species formerly assigned to it - including its close relative ''Tropeognathus'', the species portrayed in ''Series/WalkingWithDinosaurs'' (albeit [[BiggerIsBetter well oversized]] and portrayed as "the biggest pterosaur ever" -the true record holder among known pterosaurs is ''Quetzalcoatlus'' or ''Hatzegopteryx''). When someone refers to ''Ornithocheirus'', they probably mean ''Tropeognathus'' - ''Ornithocheirus'' itself is a much smaller animal and much less well-known. Even including ''Tropeognathus'', though, it's interesting that ''Ornithocheirus'' has not become a stock animal, despite its memorable appearance and how the similarly-oversized marine reptile ''Liopleurodon'' became stock. Like many pterosaurs, the two had specialized heads - with sharp pointed teeth suited for catching fish, and keel-like crests on both jaws probably used for display ("Tropeognathus" means "keeled jaw"). It was once believed that these round "keels" were used to cut through the water to better catch fish, and portrayed in such a way in classical illustrations.
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60'''South American Flyer:''' ''[[http://en.wikipedia.org/wiki/Anhanguera_(pterosaur) Anhanguera]]''
61
62* Unlike South American dinosaurs that have mostly been found in Argentina, most South American pterosaurs have been found in northern Brazil - especially in the Early Cretaceous site named Chapada do Araripe: ''[[http://en.wikipedia.org/wiki/Cearadactylus Cearadactylus]]'' and ''Anhanguera'' were among them. ''Anhanguera'' was a close relative of ''Ornithocheirus'', with the same keeled jaws but with smaller "keels". Multiple species are known, some from very complete remains. Studies done on ''Anhanguera'' fossils have revealed much information about flight mechanics. ''Cearadactylus'' ("finger of Ceara": Ceara, a small northern Brazilian province, has one of the greatest pterosaur fossil deposits in the world) was also a close relative; in life, it would have looked like an ''Anhanguera'' or ''Tropeognathus'' with a very low, nearly invisible crest. Both had very large, recurved teeth, used for catching fish. ''Cearadactylus'' was chosen as "the pterosaur" in the first ''Literature/JurassicPark'' novel: needless to say, in the [[TerrorDactyl airborne terror]] role, while ''Anhanguera'' is most well-known for starring in Series/DinosaurRevolution.
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66'''Fruit-Eater?:''' ''[[http://en.wikipedia.org/wiki/Tapejara_wellnhoferi Tapejara]]''
67
68* ''Tapejara'' was also found in Brazil in the Araripe Formation, like ''Tropeognathus'' and the two examples above. Again, a large-sized animal, it was unusual among Early Cretaceous pterodactyloids because of its ''short'' and toothless beak; toothless pterosaurs were mainly in the Late Cretaceous, among them two stock animals, ''Pteranodon'' and ''Quetzalcoatlus''. Some scientists hypothesize ''Tapejara'' was a fruit-eating, toucan-like animal, a rare example of a non-carnivorous flying reptile. Its most striking feature was [[ScienceMarchesOn once]] a huge crest, taller than the head itself (the popular ''Pteranodon''s is unpretentious in comparison). However, the owner of the crest has since been separated into a new genus, the new pterosaur ''[[http://en.wikipedia.org/wiki/Tupandactylus Tupandactylus]]''. The actual tapejara had only a small relief on its upper and lower muzzle reminiscent of ''Tropeognathus'', and a small head-crest pointing backwards. ''Tupandactylus'', named "Tapejara", appears in the same episode of Walking With featuring ''Ornithocheirus''. In 2022 a specimen of ''Tupandactylus'' was found in Brazil with integumentary remains, including melanosomes (that give dark color to the skin) and possibly branched feathers.
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72'''Terrestrial Hunter:''' ''[[http://en.wikipedia.org/wiki/Thalassodromeus Thalassodromeus]]''
73
74* The similarly-named ''[[http://en.wikipedia.org/wiki/Tupuxuara Tupuxuara]]'' was a close relative of ''Tapejara'' but placed in a distinct subfamily of the Tapejarids, the Thalassodromines (''Tapejara/Tupandactylus'' are in the Tapejarines), lived in the same places, and had similar features. Both subfamilies were toothless, head-crested, and massive-billed. The namesake of the thalassodromines, aka ''Thalassodromeus'', was once thought to be a meager skimmer like modern, well, skimmers - hence its name meaning "runner of the seas". [[ScienceMarchesOn Now it's known to not have been able to skim after all]], and was actually was a terrestrial predator like azhdarchids. With its large, robust beak, it was potentially capable of tackling comparatively larger prey than azhdarchids.
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78'''Toy Pterosaur:''' ''[[http://en.wikipedia.org/wiki/Ludodactylus Ludodactylus]]''
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80* Here's ''Ludodactylus'', a recently-discovered pterodactyloid which, [[SarcasmMode strangely]], lived [[OverlyLongGag in Early Cretaceous South America]]. Related with ''Anhanguera'' and ''Cearadactylus'' above, it has gained some notoriety, and it's easy to tell why: with its long crest paired with toothed jaws, it's the very first discovered pterosaur ''which looks just like fictional versions of Pteranodon'', transforming mere fiction in some kind of reality. Its prefix Ludo- derives from a Latin root meaning "play" or "toy", as a sort of RealLife LampshadeHanging. Its species name, ''sibbicki'', honors renowned paleoartist John Sibbick -- the illustrator of the Great Dinosaur Encyclopedia of 1985 which also depicts many stock and non-stock pterosaurs other than true dinosaurs.
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82[[/folder]]
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84[[folder:Rhamphorhynchoids]]
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88'''Dimorphodon Cousin?:''' ''[[http://en.wikipedia.org/wiki/Eudimorphodon Eudimorphodon]]''
89
90* Now we get out of the "true pterodactyls" world and enter the "rhamphorhynchs". ''Eudimorphodon'' from Late Triassic Italy is one of the most ancient pterosaurs. Despite its earliness, it already had all features of a typical pterosaur. But it was still small: ''all'' Triassic/Jurassic flying reptiles were small, at least compared to the GiantFlyer pterosaurs of the Cretaceous. ''Eudimorphodon'' was similar to the similar-named ''[[UsefulNotes/StockDinosaursNonDinosaurs Dimorphodon]]'', with the typical long, rigid tail of a "rhamphorhynchoid", but with a smaller, thinner head with complex dentition (its name means "well two-shaped teeth").
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94'''Clean Pterosaur:''' ''[[http://en.wikipedia.org/wiki/Peteinosaurus Peteinosaurus]]''
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96* The contemporary ''Peteinosaurus'' (also found in the same site) was actually more ''Dimorphodon''-like than ''Eudimorphodon''. It has appeared in ''Series/WalkingWithDinosaurs'' to represent the start of pterosaur evolution; here is shown hunting insects in flight, and then bathing itself in the mud to cool down its temperature and make its body clean, like what some birds do today. In the series seven kinds of pterosaurs are portrayed to represent ptero-evolution: first ''Peteinosaurus'', then ''Anurognathus'', then ''[[UsefulNotes/StockDinosaursNonDinosaurs Rhamphorhynchus]]'', then ''Tropeognathus'' ("Ornithocheirus") & ''Tupandactylus'' ("Tapejara"), then an unnamed kind, and finally ''[[UsefulNotes/StockDinosaursNonDinosaurs Quetzalcoatlus]]''.
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100'''Triassic Flights:''' ''[[http://en.wikipedia.org/wiki/Preondactylus Preondactylus]]''
101
102* However, neither ''Eudimorphodon'' nor ''Peteinosaurus'' are the most archaic pterosaurs known: this record may pertain to another Italian Triassic "rhamphorhynchoid", ''Preondactylus'', already with all the adaptations for flying typical of pterosaurs. Other Triassic rhamphorhynchs were discovered in the 2000s in Switzerland: ''Caviramus'' ("hollow branch") and ''[[http://en.wikipedia.org/wiki/Raeticodactylus Raeticodactylus]]'' (the latter named after a portion of the Alpine range), which showed the first bony head-crests ever appeared on pterosaurs. In the 2000s was also described ''Austriadactylus'' from Triassic [[ExactlyWhatItSaysOnTheTin Austria]]. In 2022 were described the first Triassic pterosaurs from the Southern Hemisphere (Argentina, South-America): they were related with ''Raeticodactylus''.
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106'''Missing Link?:''' ''[[http://en.wikipedia.org/wiki/Darwinopterus Darwinopterus]]''
107
108* ''Darwinopterus'' ("Darwin's wing") was a pretty big deal to the paleo-community; it was the very first pterosaur to show traits of both rhamphorhynchoids (long tail, elongated toe) and pterodactyloids (long head, long wings), making it a possible transitional species between the two groups. These little guys were insect eaters from China, and likely lived alongside little feathered dinosaurs during the Jurassic Period. ''Darwinopterus'' and its relatives may have been sexually dimorphic, with males and females differing in crest size - and one crestless specimen of ''Kunpengopterus'' (nicknamed "Mrs. T") was discovered to have died while in the process of laying an egg. Related with ''Darwinopterus'' were other pterosaurs like ''Cuspicephalus''. Other pterosaurs that combined mixed pterodactyl/rhamphorhynch traits were ''Anurognathus'' and its kin (see below).
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112'''Tiny Froggy-Friend:''' ''[[http://en.wikipedia.org/wiki/Anurognathus Anurognathus]]''
113
114* ''Anurognathus'' was one of the tiniest pterosaurs ever, just larger than a sparrow! It lived in Late Jurassic Europe, alongside many other pterosaurs and ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Archaeopteryx]]''. ''Anurognathus'' ("frog jaw") and its relatives, including the Asian ''[[http://en.wikipedia.org/wiki/Batrachognathus Batrachognathus]]'' (also meaning "frog jaw") and ''[[http://en.wikipedia.org/wiki/Jeholopterus Jeholopterus]]'' are exceptional pterosaurs - short-tailed like pterodactyloids, but with short wings and robust legs more like "rhamphorhynchoids". Most notably, however, their skulls are blunt and wide-mouthed, almost froglike in appearance, with gigantic eyes. They were probably insectivorous, possibly living and brooding on trees. Despite having been one of the most harmless Mesozoic creatures in RealLife, not even ''Anurognathus'' has managed to escape the pop-cultural fate which hits all its relatives: ''Series/{{Primeval}}'' has shown to us a sort of ZergRush [[ArtisticLicensePaleontology flying piranha]], while the more benevolent ''Series/WalkingWithDinosaurs'' has make it a Jurassic oxpecker (which there is also no evidence of).
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118'''Bigger Jurassic Flyers:''' ''[[http://en.wikipedia.org/wiki/Harpactognathus Harpactognathus]]''
119
120* ''Harpactognathus'' was one of the few pterosaurs discovered in Late Jurassic North America (in the Morrison Formation, where pterosaur fossilization is not easy): another is ''[[http://en.wikipedia.org/wiki/Mesadactylus Mesadactylus]]'' ("Mesa finger"). ''Harpactognathus'' soared above the famous stock dinosaurs of the Late Jurassic North American fauna (''[[UsefulNotes/StockDinosaursTrueDinosaurs Stegosaurus, Allosaurus, Diplodocus]]'' etc.) and was quite possibly the ''only'' pterosaur that had a long tail, a (low) head crest, and teeth. ''Harpactognathus'' is thought to have been omnivorous like its relative ''Scaphognathus'', although potentially more predatory of small vertebrates due to its size. It was indeed quite large for rhamphorhynch standards; with an estimated wingspan of 8 ft (2.4 m), it was the biggest known rhamphorhynchoid pterosaur until the recent (2022) description of the very short-named ''[[http://en.wikipedia.org/wiki/Dearc Dearc]]'', an earlier rhamphorhynch from Middle Jurassic Britain (the ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Megalosaurus]]'' time) which maybe reached 10 ft/3 m of wingspan or even more. Both were, however, still smaller than several "mid-sized" cretaceous pterodactyloids like ''Tropeognathus'' or ''Dsungaripterus'', and much smaller than the huge late cretaceous ''Quetzalcoatlus'', ''Hatzegopteryx'' and ''Pteranodon''.
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124'''Pterosaur or Crocodile?:''' ''[[http://en.wikipedia.org/wiki/Rhamphocephalus Rhamphocephalus]]''
125
126* The English Middle Jurassic ''Rhamphocephalus'', with a name similar to ''Rhamphorhynchus'', has traditionally been thought a rhamphorhynchoid pterosaur, but its original specimen has revealed as recently as 2018 to be a sea-crocodile. Other rhamphorhynchoid pterosaurs were actually such. ''[[http://en.wikipedia.org/wiki/Scaphognathus Scaphognathus]]'' was a small European generalist contemporary of the more well-known ''Rhamphorhynchus'' and ''Pterodactylus''. ''[[http://en.wikipedia.org/wiki/Dorygnathus Dorygnathus]]'' was likely adapted to a life at sea, with its long narrow wings and sharp, interlocking teeth, perfect for keeping a hold on slippery fish, while the also Early Jurassic "Campylognathus" (today renamed ''[[http://en.wikipedia.org/wiki/Campylognathoides Campylognathoides]]'') was probably more terrestrial and Dimorphodon-like. ''Campylognathoides'' is unusual for its long and heavily-muscled forelimbs, almost "gorilla-armed" in comparison to other pterosaurs. The equally-sesquipedalian ''[[http://en.wikipedia.org/wiki/Angustinaripterus Angustinaripterus]]'' (17 letters for both animals' genus names) was similar to ''Rhamphorhynchus '' but lived in Middle Jurassic China.
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130[[/folder]]
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134'''Marine Reptiles:'''
135
136[[folder:Ichthyosaurs]]
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138----
139
140'''A Lethal Childbirth:''' ''[[http://en.wikipedia.org/wiki/Stenopterygius Stenopterygius]]''
141
142* The small (2.4 m) namesake ''[[UsefulNotes/StockDinosaursNonDinosaurs Ichthyosaurus]]'' is the pop culture member of the ichthyosaur group because it was the first ever discovered (1821, ''before'' the first dinosaur): lived in Early Jurassic seas, but has been used as a "wastebin taxon" for undetermined/generic small ichthyosaurs (a bit like what happened to the dinosaur ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Megalosaurus]]''). With its dolphin-like shape, ''Ichthyosaurus'' had no particular traits compared to other ichthyosaurs, as well as the contemporary, almost-identical ''Stenopterygius''. The latter is worth of note, however, because is the species from which the famous "mother-with-young-inside" skeleton comes from. That mother died just when its child was going out of its body. This fossil probably inspired the [[Series/WalkingWithDinosaurs WWD producers]] who depicted a scene of a mother killed with a still-not born young, but attributing it to another ichthyosaur, ''Ophthalmosaurus''.
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145
146'''Huge Eyes and Toothless Mouth:''' ''[[http://en.wikipedia.org/wiki/Ophthalmosaurus Ophthalmosaurus]]''
147
148* Ichthyosaurs reached their prime in the Jurassic. But, surprisingly, in the Late Jurassic they had already become rare. ''Ophthalmosaurus'' is the most well-known among these Late Jurassic kinds. Unusual for having toothless jaws, its name means "eye lizard" because of its [[ExactlyWhatItSaysOnTheTin enormous orbits]]: it's often said to have had "the largest eyes of all vertebrates ever" (in respect to the whole body). Even though it was actually a specialized ichthyosaur, ''Ophthalmosaurus'' shows up in Series/WalkingWithDinosaurs' episode dedicated to marine reptiles as the icon of the whole ichthyosaur group.
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151
152'''Swordfishes in the Jurassic?:''' ''[[http://en.wikipedia.org/wiki/Eurhinosaurus Eurhinosaurus]]''
153
154* Most ichthyosaurs were Early Jurassic just like ''Ichthyosaurus'' and ''Stenopterygius'', and some had some specialization. ''Eurhinosaurus'' ("well-nosed lizard"), for example, had a swordfish-like head plus tiny teeth on its "sword"; the same about its relative ''{{Excalib|ur}}osaurus''. They were middle-sized ichthyos, and could have used their prominence like a modern swordfish or maybe a sawfish, but there are no sure indications. There were also bigger guys in the Early Jurassic seas: ''[[http://en.wikipedia.org/wiki/Temnodontosaurus Temnodontosaurus]]'' was much larger than ''Ichthyosaurus'', reaching 8 m or more in length, as a modern killer whale. It was once called ''Leptopterygius'' ("thin flipper") and was one of the apex predators of its time, but its shape was that of a generic ichthyosaur. Its prey could have included smaller sea-reptiles like ''Ichthyosaurus'' proper and the original plesio, ''[[UsefulNotes/StockDinosaursNonDinosaurs Plesiosaurus]]''.
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157
158'''Titans of the Oceans'''
159
160* However, the largest ichthyosaurs known to science were surprisingly the earliest, Triassic ones: ''[[UsefulNotes/StockDinosaursNonDinosaurs Shonisaurus]]'' reached 18m or even more and weighed about 30 tonnes, roughly the size of a modern sperm whale. Found in North America in 1976, the shonisaur was traditionally considered the biggest ichthyosaur, but ''[[UsefulNotes/StockDinosaursNonDinosaurs Shastasaurus sikanniensis]]'' has recently revealed to be even larger at over 20m and weighing almost 70 tonnes! Another smaller (but still very big) close relatives of both was ''[[http://en.wikipedia.org/wiki/Himalayasaurus Himalayasaurus]]'' found in [[ExactlyWhatItSaysOnTheTin the Himalayas]] (still covered by seas at the time: they emerged out of water only in the Cenozoic). These early giant ichthyosaurians had also several specializations: their four flippers were long and plesiosaur-like, all of similar length (unusually for ichthyosaurs); their body was stockier than most other ichthyosaurs. We don't know if they had a dorsal fin or not, but almost surely did they have the typical caudal fin of the Jurassic ichthyosaurs, although more primitive and less-developed. Formerly thought to feed primarily on squid like modern sperm whales, it is now understood that these ichthyosaurs were likely apex predators, and would have feasted upon a variety of large fish, sharks and smaller marine reptiles, in addition to the aforementioned squid. These ichthyosaurs are candidates for "the biggest marine reptile ever" title, alongside the biggest mosasaurs and pliosaurs; and yet, have not received much attention even in TV documentaries for now.
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163
164'''As Big as the Blue Whale?:''' The "Lilstock Ichthyosaur"
165
166* In 2016, fragmentary jawbones of possibly much larger Shastasaurid were discovered in England. Without enough remains yet found to name the species, it's known for now as simply the "Lilstock ichthyosaur", and if its proportions are comparable to the rest of Shastasauridae then it could have been 26 to 30m long and weighed around 200 tonnes, making it the only known animal to rival the blue whale in size. Given their size, the shastasaurs probably didn't feed themselves only on small fish or ammonites; the modern giant sperm-whale, despite its lacking of teeth in the upper jaw, is capable to swallow ''whole'' 12-m long giant and colossal squids, or large sharks.
167
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169
170'''Primitive and Mosasaur-like:''' ''[[http://en.wikipedia.org/wiki/Cymbospondylus Cymbospondylus]]''
171
172* On the other hand, the very un-ichthyosaur-like ''Cymbospondylus'' has received a "better" treatment than the giant shastasaurs, showing up as the "biggest ichthyosaur" in the Triassic seas in ''Series/SeaMonsters''. Even though it was large as well, reaching 9m/27ft, it was far smaller than ''Shonisaurus'' and ''Shastasaurus'' (the series' accompanying book got this right). Unlike the latest two, ''Cymbospondylus'' was one of the most basal ichthyosaurs known, being more similar to large evolved mosasaurs like ''Plotosaurus'' (see further), with only a hint of caudal fin and a very elongated body. However, its head was already ichthyosaurian, and had no visible neck. Interestingly, the famous model of ''[[UsefulNotes/StockDinosaursNonDinosaurs Ichthyosaurus]]'' in the Crystal Palace Park in London incidentally resembles a bit a ''Cymbospondylus''.
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175
176'''The Start...'''
177
178* In dinosaur books, the traditional prototypical Triassic ichthyosaur has been ''[[UsefulNotes/StockDinosaursNonDinosaurs Mixosaurus]]''. Even smaller than a human and with a still underdeveloped caudal fin, it had already the classic fish-like form of more advanced ichthyosaurs, showing how the ichthyosaurs' strong adaptations to water were already achieved well before the success of, say, the land-living dinosaurs and the flying pterosaurs. ''Californosaurus'' (found in [[ExactlyWhatItSaysOnTheTin California]]) and ''[[http://en.wikipedia.org/wiki/Grippia Grippia]]'' were other relatively small basal ichthyosaurs from Triassic. The two animals' prey might have included [[UsefulNotes/StockDinosaursNonDinosaurs ammonites]], fishes of every kinds, crustaceans etc. Like what happens with modern sea-mammals, different kinds of ichthyosaurs arguably ate different sources of food, even though none of them was probably a filter-feeder like the modern baleen whales. Other bigger ichthyosaurs known from the Triassic were discovered more recently. ''[[http://en.wikipedia.org/wiki/Besanosaurus Besanosaurus]]'' was found in the Alps (the highest mountains of Europe, that emerged only during the Cenozoic Mammal Age 200 my after: at the time there were shallow seas instead) in the 1990s and was 6 m long, not much smaller than ''Cymbospondylus'' above; ''[[http://en.wikipedia.org./wiki/Thalattoarchon Thalattoarchon]]'' ("ruler of the seas") found in the 2010s was as large as the latter, and one of the top predators of the Triassic seas as well.
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180----
181
182'''...and The End'''
183
184* Very few ichthyosaurs survived in the Early Cretaceous: among them, the toothed and quite unspecialized ''[[http://en.wikipedia.org/wiki/Platypterygius Platypterygius]]''. Ichthyosaurs went to extinction ''far'' before the asteroid/comet, about 100 million years ago: since they were the best adapted to sea among all Mesozoic reptiles, the reason of this remains still unclear. They may have been outcompeted by mosasaurs (who started to roam the oceans just in that period) and/or sharks and bony-fish, which started to diversify in the same period but were much more ancient than the ichthyosaurs, having appeared well before the Triassic. On the other hand, plesiosaurs (both long- and short-necked), mosasaurs and ammonites reached the moment of the Great Collision of 65 mya, killed by humongous tsunamis and then by the lack of food due to the scarce solar light provoked by the global "dust-cloud" in the skies, that blocked the photosynthesis also in the seas other than in the drylands. Sea-turtles, sharks and bony-fish managed to survive the catastrophe and are swimming in the seas still today.
185
186----
187
188'''The Anachronism:''' ''[[https://en.wikipedia.org/wiki/Malawania Malawania]]''
189
190* It was long thought that the Ophthalmosaurids (the family of ''Ophthalmosaurus'' and ''Platypterygius'') were the ''only'' ichthyosaurs to survive past the Late Jurassic. Which is what made the ichthyosaur eventually named ''Malawania anachronus'' such a surprise. It was presumed since its 1952 discovery to be a ''Triassic'' ichthyosaur, on account of its very basal features. Instead, it was determined that the rock it was embedded in dated to the Early ''Cretaceous''. Based on its features, ''Malawania'' seems to be most closely related to ''Ichthyosaurus'' itself...a genus that vanished from the fossil record 70 million years earlier. While it's now obvious that at least some basal ichthyosaurs survived into the Cretaceous, the lack of any Middle or Late Jurassic fossils of them leaves ''Malawania''[='=]s lineage uncertain. It's hypothesized that the small, dolphin-like ichthyosaurs were able to survive for so long by confining themselves to relatively shallow lagoons, thus avoiding competition with larger ichthyosaurs, pliosaurs, sharks and mosasaurs.
191
192----
193
194[[/folder]]
195
196[[folder:Plesiosaurs]]
197
198----
199
200'''The Last Plesiosaurs:''' the [[http://en.wikipedia.org/wiki/Elasmosauridae Elasmosaurids]]
201
202* Plesiosaurs are divided in two main lineages: plesiosauroids (the "plesiosaurs" ''sensu stricto'') and pliosauroids (the "pliosaurs"), which separated from plesiosaurs in the Triassic. Other than the spectacular ''[[UsefulNotes/StockDinosaursNonDinosaurs Elasmosaurus]]'', there were many other animals in the plesiosauroid subgroup. The closest ''Elasmosaurus'' relatives are called "elasmosaurids" from their namesake, among them ''Styxosaurus'', ''Mauisaurus'', and ''Hydrotherosaurus'': some of them were as large as the latter and sometimes even more. They generally lived in the Late Cretaceous, and were among the last sea reptiles before the Cretaceous-Palaeogene boundary... except for the fanciful StockNessMonster of course.
203
204----
205
206'''Heads or Tails?'''
207
208* Let's talk a bit more about the prototypical ''Elasmosaurus'': it was victim of an astonishing paleontological blunder in the middle of the 19th century, when it was first discovered. Before the notorious [[http://en.wikipedia.org/wiki/Bone_Wars Bone Wars]] began in the USA, Edward Cope (one of the two "warrior" scientists) discovered its first skeleton, but its skull was found separated by the rest. Looking at the unbelievable length of its neck and the comparatively short tail, Cope decided, after infinite second thoughts, to put the skull... ''on its tail-tip''. The other paleontologists obviously laughed at Cope when the mistake was cleared, and the legend says that Othniel Marsh (his future rival) was among them; and this would have caused the hate between the two, and thus, the upcoming Bone Wars.
209
210----
211
212'''Stones For Lunch:''' ''[[http://en.wikipedia.org/wiki/Cryptoclidus Cryptoclidus]]''
213
214* Among non-elasmosaur plesiosauroids, ''Cryptoclidus'' (sometimes misspelled "Cryptocleidus") and the prototypical ''[[UsefulNotes/StockDinosaursNonDinosaurs Plesiosaurus]]'' are the most portrayed. The former was medium-sized and the classic Late Jurassic plesiosauroid, with a typical look but a not-so-oversized neck as the elasmosaurs; some remains show stones in its ribcage, whose purpose is uncertain. It could have been a prey of the famed ''[[UsefulNotes/StockDinosaursNonDinosaurs Liopleurodon]]''. ''Plesiosaurus'' was even smaller and even shorter-necked, and lived in Early Jurassic along with many ichthyosaurs. The relatively large ''[[http://en.wikipedia.org/wiki/Muraenosaurus Muraenosaurus]]'' lived in a time between ''Plesiosaurus'' and ''Cryptoclidus'', in the Middle Jurassic.
215
216----
217
218'''Short-Necked Longnecks:''' ''[[http://en.wikipedia.org/wiki/Dolichorhynchops Dolichorhynchops]]'' & ''[[http://en.wikipedia.org/wiki/Trinacromerum Trinacromerum]]''
219
220* Even though are little-known compared with other relatives, Polycotylids are interesting because they were the only ''short-necked'' plesiosauroid subgroup. They lived in the Late Cretaceous, and achieved a shape deceptively similar to pliosauroids (see below), but were far smaller, often man-sized. However, one [[{{Documentary}} National Geographic Special]] featured one polycotylid (''Dolichorhynchops'') as the main character. Another example of polycotylid is ''Trinacromerum'', whose name recalls that of Trinacria (the ancient name of the Italian island of Sicily, meaning "three-corners" because of its triangular shape).
221
222----
223
224'''Long-Necked Shortnecks:''' ''[[http://en.wikipedia.org/wiki/Macroplata Macroplata]]'' & ''[[http://en.wikipedia.org/wiki/Rhomaleosaurus Rhomaleosaurus]]''
225
226* Unlike plesiosauroids, pliosaurs hadn't a great variety in the Mesozoic: most of them had the same size and the same appearance of the two stock members, the gigantic ''[[UsefulNotes/StockDinosaursNonDinosaurs Kronosaurus]]'' and ''Liopleurodon'' (although the former is about 20 ft smaller than first thought). There were smaller pliosaurs as well, though: The Middle Jurassic ''[[http://en.wikipedia.org/wiki/Peloneustes Peloneustes]]'' ("mud swimmer") is a good example. Some pliosaurs (ex. the very short-necked ''[[http://en.wikipedia.org/wiki/Brachauchenius Brachauchenius]]'') managed to reach the end of the Cretaceous and lived alongside ''Elasmosaurus'', ''Tylosaurus'' and ''Archelon'', but are rarely considered unlike their earlier predecessors, suffering the rivalry of the aforementioned stock sea reptiles. However, the earliest pliosaurs were very different-looking than a ''Liopleurodon'': Early Jurassic ''Macroplata'' ("big plate") and ''Rhomaleosaurus'' (once often confused with ''"Thaumatosaurus"'', "wonder lizard"), and Late Triassic ''[[http://en.wikipedia.org/wiki/Thalassiodracon Thalassiodracon]]'' ("sea-dragon") had all a ''long'' neck and a ''small'' head. At the Early Jurassic, plesiosauroids and pliosauroids weren't still differentiated from each other: ''Plesiosaurus'' and ''Macroplata'' may easily get confused. Late Jurassic forms were well-defined, ''Liopleurodon'' and ''Cryptoclidus'' looked ''very'' differently. Even more the Cretaceous kinds: ''Kronosaurus'' and ''Brachauchenius'' had even shorter necks than ''Liopleurodon'' or ''Pliosaurus'', and the Elasmosaurids had even longer necks than ''Cryptoclidus'' or ''Muraenosaurus''.
227
228----
229
230[[/folder]]
231
232[[folder:Mosasaurs]]
233
234----
235
236'''"Antediluvian" Sea Reptiles'''
237
238* When non-bird dinosaurs were still unknown, sea-reptiles were already well-known to science. Mosasaurs in particular have had a crucial role in vertebrate paleontology: their namesake, ''[[UsefulNotes/StockDinosaursNonDinosaurs Mosasaurus]]'' has been the [[strike:very first]] second "antediluvian reptile" ever discovered, at the end of the 18th century in Netherlands (the record-holder is ''[[UsefulNotes/StockDinosaursNonDinosaurs Pterodactylus]]''). The "mosasaur" was described by the Father of Paleontology, French naturalist [[http://en.wikipedia.org/wiki/Georges_Cuvier Georges Cuvier]], and its first found remains were object of an awesome tangle, with the jaws that were lost during the battles of the European Napoleonic Era. One detail is astounding: the mosasaur was ultimately discovered... thanks to [[IDoNotDrinkWine some bottles of wine]] offered as a reward for who would have ultimately found them.
239
240----
241
242'''Teeth for Any Food:''' ''[[http://en.wikipedia.org/wiki/Hainosaurus Hainosaurus]]'' & ''[[http://en.wikipedia.org/wiki/Globidens Globidens]]''
243
244* All mosasaurs lived in the Late Cretaceous, and thus were short-lived compared to other sea reptiles. The gigantic ''[[UsefulNotes/StockDinosaursNonDinosaurs Tylosaurus]]'' and ''[[UsefulNotes/StockDinosaursNonDinosaurs Mosasaurus]]'' are the two stock genera, often confused each other in paleo-art. Among other "mosas", we can mention: the huge ''Hainosaurus'', believed by some the largest mosasaurian; the rather ichthyosaur-like ''Plotosaurus'' ("swimming lizard"), a specialized mosasaur which was as large as ''Tylosaurus'' or even more; the much smaller, more traditional-looking ''[[http://en.wikipedia.org/wiki/Platecarpus Platecarpus]]'' and ''[[http://en.wikipedia.org/wiki/Clidastes Clidastes]]'', both primitive kinds very common in the famous inland sea that covered central North America at the time (which was also home to ''Tylosaurus''); ''Halisaurus'' ("saltwater lizard") and ''Goronyosaurus''; ''Gavialimimus'' ("gharial-mimic"), described in 2020; and the unusual ammonite eater ''Globidens'' ("globe tooth"), with a typical mosasaur shape but blunt teeth: convergently with the Placodonts, see the next folder.
245
246----
247
248'''The Ancestor?:''' ''[[http://en.wikipedia.org/wiki/Dallasaurus Dallasaurus]]''
249
250* Perhaps the first mosasaurian was the amphibious ''Dallasaurus'' (named after Dallas city), which had ''functioning legs''. While some scientists speculated that mosasaurs evolved from the same ancestor as snakes, the discovery of legless snakes predating ''Dallasaurus'' has debunked that, and it is now known that they are varanoids, making them the badass [[SuperNotDrowningSkills marine]] cousins of monitor lizards such as the Komodo dragon and ''Megalania''. More recently a freshwater mosasaur has been discovered, named ''[[http://en.wikipedia.org/wiki/Pannoniasaurus Pannoniasaurus]]'' and it wasn't a small animal like ''Dallasaurus'', it had a length considerable to the largest living crocodilians and likely took a niche similar to them, ambushing dinosaurs as they came to drink.
251
252----
253
254'''A FIN-tastic Discovery''': ''[[http://en.wikipedia.org/wiki/Plotosaurus Plotosaurus]]'' & ''[[http://en.wikipedia.org/wiki/Prognathodon Prognathodon]]''
255
256* For decades, it was assumed that Mosasaurs swam like crocodiles or sea snakes: undulating with their tails and paddling with their flippers. In 2010, fossils of ''Prognathodon'' ("protruding tooth") turned this assumption on its head by showing a striking example of convergent evolution with Metriorhynchid crocodylomorphs (the "marine crocodiles", see below) and Ichthyosaurs: at least some species of mosasaurs - like the aforementioned evolved ''Plotosaurus'' - had developed shark-like tail-flukes, a far more efficient method of swimming than the previously assumed undulation. Whether all species of mosasaurs possessed this adaptation or whether they gradually evolved from undulating to using only their tails is currently unknown.
257
258----
259
260'''Color me Black-and-White'''
261
262* In 2014, paleontologists discovered melanosomes (black pigments) in fossil remains of a number of prehistoric marine reptiles - including not just mosasaurs but pliosaurs, ichthyosaurs, and even turtles. The study determined that - like many extant marine animals - prehistoric sea animals were often counter-shaded, with a dark back and a light belly that would have served as a form of camouflage. However, this doesn't mean that there weren't exceptions of more brightly-colored sea reptiles; the modern filter-feeding [[http://en.wikipedia.org/wiki/Whale_Shark Whale Shark]] (the biggest extant fish) has a striking coloration made of white dots and lines elegantly running across its whole body, making a true design a bit like the one of some modern land mammals such as [[ZebrasAreJustStripedHorses zebras]] and [[PantheraAwesome big cats]].
263
264----
265
266[[/folder]]
267
268[[folder:Placodonts, Nothosaurs & Others]]
269
270----
271
272There were many other groups of sea reptiles in the Mesozoic other than the previous ones. Among them, giant turtles in the Cretaceous (such as ''[[UsefulNotes/StockDinosaursNonDinosaurs Archelon]]''); sea crocodiles in the Jurassic, some of them very fish-like (such as ''[[UsefulNotes/StockDinosaursNonDinosaurs Metriorhynchus]]''); while the Triassic was represented by two primitive, still partially terrestrial groups: placodonts and nothosaurs.
273
274----
275
276'''From pseudo-Iguanas to pseudo-Turtles:''' ''[[http://en.wikipedia.org/wiki/Henodus Henodus]]'' & ''[[http://en.wikipedia.org/wiki/Psephoderma Psephoderma]]''
277
278* [[http://en.wikipedia.org/wiki/Placodontia Placodonts]] and [[http://en.wikipedia.org/wiki/Nothosaur Nothosaurs]] were the two main groups of Triassic sea reptiles, both relatively small compared to the most famous Jurassic-Cretaceous marine reptiles, but still large animals compared with other basal Triassic reptiles. Both are still partially terrestrial and with functioning limbs: if compared with plesiosaurs, they were like seals or otters compared with whales or manatees. Placodonts were the most specialized. They were bulky animals with strong jaws and crushing teeth specialized to eat shellfish; the most evolved of them (ex. ''[[http://en.wikipedia.org/wiki/Placochelys Placochelys]]'', ''Psephoderma'', ''[[http://en.wikipedia.org/wiki/Cyamodus Cyamodus]]'', and ''Henodus'') had an armor and were very turtle-like, with a beak, weak tails, and swum with their limbs like turtles. ''Henodus'' was particularly turtle-like, with its flat broad shell and stubby tail. ''Psephoderma'' was also peculiar, because of its armor divided in two pieces, like some modern turtles that have hinged shells (ex. the [[http://en.wikipedia.org/wiki/Terrapene_carolina Common Box Turtle]], but also others). However, the most basal placodonts (ex. the namesake ''[[UsefulNotes/StockDinosaursNonDinosaurs Placodus]]'') were almost armor-less, with "incisor"-like teeth and a long, robust tail for swimming, resembling a bit the modern Galapagos islands' marine iguana. Placement of placodonts in the reptilian phylogenetic tree is still uncertain, but are traditionally regarded as distant plesiosaur relatives, thus probably not related with turtles despite their resemblance. However, as recent evidence indicates that plesiosaurs themselves may have been distant turtle relatives, placodonts may have been as well.
279
280----
281
282'''Sea-Dwellers or Lake-Dwellers?:''' ''[[http://en.wikipedia.org/wiki/Ceresiosaurus Ceresiosaurus]]'' & ''[[http://en.wikipedia.org/wiki/Neusticosaurus Neusticosaurus]]''
283
284* Nothosaurs were very different-looking than placodonts: slender fish-eaters with streamlined bodies, flat tails, long necks and long, thin jaws with pointed teeth. Some of their features were plesiosaur-like: this because nothosaurs were close plesiosaur relatives, and some of them might have even been their ancestors. However, nothosaurs still swum using their tails like modern crocodilians, while their possible descendants the plesiosaurs had rigid body and used their flippers to propel themselves through the water. ''[[UsefulNotes/StockDinosaursNonDinosaurs Nothosaurus]]'' is considered the prototype of the nothosaur group and was 4m/12ft long, but the most basal nothosaurs were much smaller, like ''Neusticosaurus'' (also named "''Pachypleurosaurus''"). The most evolved nothosaurs were practically plesiosaurs: ex. ''[[http://en.wikipedia.org/wiki/Pistosaurus Pistosaurus]]''. Other examples of nothosaurs include the large evolved ''Ceresiosaurus'' and the smaller ''[[http://en.wikipedia.org/wiki/Lariosaurus Lariosaurus]]'', whose names are a reference to some alpine lakes (the Lake of Lugano and the Lake of Como respectively), between Switzerland and Italy, where their fossils were dug out. One ''Ceresiosaurus'' fossil was found surrounded by several specimens of the far smaller ''Neusticosaurus'': some believed they died when they're scavenging the carcass of their bigger relative ''Ceresiosaurus''.
285
286----
287
288'''Uncertain Relationships:''' ''[[http://en.wikipedia.org/wiki/Askeptosaurus Askeptosaurus]]'' & ''[[http://en.wikipedia.org/wiki/Hupehsuchus Hupehsuchus]]''
289
290* Another group of Triassic aquatic reptiles, Thalattosaurs -- lit. "sea lizards", for example ''Askeptosaurus italicus'' ("italicus" = Italian) and ''Endennasaurus'', also found near the aforementioned alpine lakes[[note]] Many other Triassic reptiles have been discovered as well near these lakes: for example ''[[UsefulNotes/StockDinosaursNonDinosaurs Tanystropheus]]'', ''Neusticosaurus'', drepanosaurids, early ichthyosaurs like ''Besanosaurus'', and even some of the earliest pterosaurs (''Eudimorphodon'').[[/note]], resembled miniaturized nothosaurs, but weren't related with them. Others, like ''[[http://en.wikipedia.org/wiki/Helveticosaurus Helveticosaurus]]'', were perhaps related with placodonts. Still others, the hupehsuchians like ''Hupehsuchus'' and ''[[http://en.wikipedia.org/wiki/Nanchangosaurus Nanchangosaurus]]'', looked like a cross between an ichthyosaur and a placodont, and were perhaps the ancestor of ichthyosaurs. One recently-discovered, ''[[http://en.wikipedia.org/wiki/Eretmorhipis Eretmorhipis]]'', had unusually seven digits in its hands and six in its feet, like some ichthyosaurians and the earliest land-vertebrates (''Ichthyostega'', ''Hynerpeton'' etc.). In the Permian, one of the earliest aquatic reptiles was ''[[http://en.wikipedia.org/wiki/Claudiosaurus Claudiosaurus]]'' of Madagascar, a sort of small but bulky-bodied swimming lizard: some think it could be a distant ancestor of turtles, but this is unproven. Another was ''[[http://en.wikipedia.org/wiki/Hovasaurus Hovasaurus]]'' from Late Permian/Early Triassic, also found in Madagascar: a basal true diapsid like ''Claudiosaurus'', it was similar to a slender swimming lizard.
291
292----
293
294'''Successful Underdogs:''' the [[http://en.wikipedia.org/wiki/Choristodera Choristoderes]]
295
296* While technically not exclusively marine, choristoderes (better known as champsosaurs) are thought to have been fully aquatic, even in freshwater ecosystems - to the point that in some species only the females had limbs that were strong enough to move on land. Originated in the Triassic period, champsosaurs were once considered "eosuchians". They were often similar to miniaturized crocodiles (but not related at all with them), and are of particular interest as they managed to survive beyond the Mesozoic and into the Cenozoic where most of their brethren went extinct at the K-Pg extinction event. They are the ''only'' now-extinct group of reptiles that [[SoleSurvivor lasted after the end of the Mesozoic era]]. The Late Cretaceous ''[[UsefulNotes/StockDinosaursNonDinosaurs Champsosaurus]]'' is the namesake of the group. Croc-shaped but without the armor, it was only 1.5 m/5 ft long: a perfect underdog when compared with its neighbour, the 45 ft long, elephant-sized "true crocodilian" ''[[UsefulNotes/StockDinosaursNonDinosaurs Deinosuchus]]''. Among Cenozoic choristoderes ''[[http://en.wikipedia.org/wiki/Lazarussuchus Lazarussuchus]]'' is named after Lazarus, the character resuscitated by Jesus (a reference to its ScienceMarchesOn story).
297
298----
299
300'''Split Jaw?:''' ''[[https://en.wikipedia.org/wiki/Atopodentatus Atopodentatus]]''
301
302* One of the strangest marine reptiles ever discovered, this Triassic creature had a body structure similar to that of the aforementioned ''Placodus''. But that's not what so strange about this guy. The name means "Unusual dentation", and for good reason: it was originally assumed that the creature's upper mandible was [[http://scinews.ro/wp-content/uploads/2014/02/Atopodentatus_unicus.jpg split into a strange zipper-like structure.]] Two new specimens [[http://advances.sciencemag.org/content/2/5/e1501659 described in 2016]] showed that the processes of the mandible thought to form a zipper-like structure actually faced laterally, giving the animal's head a hammerhead-like shape. Before 2016 it was interpreted as likely a filter feeder instead of an active predator, swimming into shallow waters to prey on small microscopic organisms. The 2016 discoveries suggest it might have actually been an herbivore, scraping algae off the substrate underwater.
303
304----
305
306[[/folder]]
307
308----
309
310'''Extant Reptile Groups:'''
311
312[[folder:Crocodilians]]
313
314----
315
316Contrary to what many shows make to believe, dinosaurs, pterosaurs, ''Dimetrodon'' and sea reptiles ''were not'' the ancestors of any modern reptile; instead, some of them were at the origin of ''bird and mammal groups''. However, there were ''true'' relatives of modern reptilian species in the past as well, and they have existed since the beginning of the Age of Dinosaurs or even before that time (except snakes, which are a rather young group evolutionarily speaking). Some of these animals were rather similar to their modern relatives, while other were quite different (remember that ''every'' animal group does evolve during the time). In general, most media and even documentaries will go with the larger species of each group. The smaller relatives are almost never mentioned because [[RuleOfCool they are not spectacular enough]], even though they were more abundant that their gigantic versions, just like what happens to modern animals in general.
317
318----
319
320'''An Enduring Success'''
321
322* Here we're going to talk about crocodilians, the only surviving members of the clade [[http://en.wikipedia.org/wiki/Pseudosuchia Pseudosuchia]]. They are the only extant reptiles that it wouldn't be too wrong confounding them with dinosaurs. OK, they aren't dinos in a strict sense, but they were their closest non-avian relatives, and shared with dinosaurs ''much more'' traits it may seem at first glance. Both dinosaurs and crocs have/had alveolate teeth with a bit of heterodonty: to make things clear, their teeth were more similar in their structure to the ''mammalian'' ones than, to say, those of lizards. Both dinos and crocs show complex parental care, again ''just'' like mammals and unlike lizards/turtles. And both dinos and crocs did descend from ''bipedal'' ancestors. Quite so. The first common ancestors of both dinos and crocs, the Triassic archosaurs (see further), were a sorta mix-up of dinosaurian and crocodilian features, and some ancient croc relatives were deceptively dinosaur-like - the most striking case is the ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Struthiomimus]]''-like ''Effigia''. But at the Jurassic, their evolution diverged more, and since then, separating crocs from dinos becomes an easier task. However, don't think ancient crocs were boring things: it's anything but. Within their enduring success, they were almost as diversified as dinosaurs, and their size and body plan were ''very'' variable. Some were as small as a chameleon, others larger than ''T. rex''. Some were powerful predators of large land animals; other became fish-lovers or insect-hunters; and some were even aquatic ''filter-feeders''. As a group, they roamed all the three main Earth environments: land, oceans and freshwater - even though the latter was their favourite, because here they didn't suffer any competition, unlike dinosaur-ruled lands and sea reptile-ruled seas. Some examples of ancient crocodylomorphs are following.
323
324----
325
326'''Supercrocs weren't only Cretaceous Things:''' ''[[http://en.wikipedia.org/wiki/Rhamphosuchus Rhamphosuchus]]''
327
328* In old traditional taxonomy crocodylomorphs were divided in three suborders: Protosuchians ("first crocodiles"), Mesosuchians ("middle crocodiles"), and Eusuchians ("true crocodiles"). The first two, however, are paraphyletic, since the early protosuchians gave rise to the more advanced mesosuchians, which in turn gave rise to the even more evolved eusuchians. Let's start with giant freshwater crocodylomorphs, [[RuleOfCool for obvious reasons]]. ''[[UsefulNotes/StockDinosaursNonDinosaurs Sarcosuchus]]'' ("meat-eating croc") was not an Eusuchian like ''[[UsefulNotes/StockDinosaursNonDinosaurs Deinosuchus]]'' and modern crocodilians, but only a crocodylomorph distantly related with true crocodilians. The shape of ''Sarcosuchus'' was that of a gigantic gharial, with long thin jaws and numerous needle-like teeth. First found in Cretaceous Northern Africa in the same habitat of ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Spinosaurus]]'', it was recently found also in South America, where ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Giganotosaurus]]'' roamed. 15 m long, ''Sarcosuchus'' was basically the same bulk of these giant theropods. Recently CGI documentaries have popularized the ''Deino-'' and the ''Sarco-'' ''-suchus'' with the nickname “supercrocs”. Given their size they could have eaten giant dinosaurs if they’d the chance, and some portraits show them defeating even the biggest theropods. In RealLife, it's more likely such powerful predators tried to avoid each other, but at least ''Deinosuchus'' is known to have attacked living tyrannosaurs (not ''T.rex''es but smaller kinds, like ''Albertosaurus''), shown by a leg bone that healed after the bite. Not everyone knows, however, that two enormous crocs lived just ''few million years ago'', in full Mammal Age, when the first hominids just started their evolutionary journey: the giant false-gharial ''Rhamphosuchus'' ("sharp-snouted croc") from India and the giant caiman ''Purussaurus'' ("Purus lizard": Purus is one of the biggest tributaries of the Amazon River) from South America. And they were at least as big as (if not bigger than) the two dinosaur-eating docu-stars. Some think ''Rhamphosuchus'' was partially marine like the modern saltwater crocodile: if so, it could have encountered the famous giant shark [[UsefulNotes/StockDinosaursNonDinosaurs Megalodon]] and the giant sperm-whale ''[[UsefulNotes/StockDinosaursNonDinosaurs Livyatan]]'', which were its contemporaries. And the three were of similar length, though the shark and the whale were more massive and with much bigger and more powerful jaws and teeth than the slimmer ''Rhamphosuchus''.
329
330----
331
332'''The Heaviest?:''' ''[[http://en.wikipedia.org/wiki/Purussaurus Purussaurus]]''
333
334* On the other hand, ''Purussaurus'', being related with modern caimans that are strictly freshwater animals, probably never went in the seas, but was probably more massively-built than ''Rhamphosuchus'' and weighed even more. Today gators and caimans tend to be bulkier than gharials, even though the latter can be longer. The recently (2012) discovered ''[[http://en.wikipedia.org/wiki/Aegisuchus Aegisuchus]]'' might have been even larger: measurements of its only remain, a skull (which was larger than a human by itself) suggest an animal over 20 meters long, making ''Aegisuchus'' the longest non-marine predator to ever live -- although it's much more probable that its skull was larger in comparison to its body than other crocodylomorphs. Unlike ''Rhamphosuchus'' and ''Purussaurus'', ''Aegisuchus'' lived in the Dinosaur Age, in the Cretaceous Morocco, and was a basal true eusuchian. From Algeria comes the first specimen found of another interesting yet much smaller crocodylomorph: ''[[http://en.wikipedia.org/wiki/Dyrosaurus Dyrosaurus]]'', not to be confused with the ornithischian dinosaur ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Dryosaurus]]''. 18 ft/6 m long, gharial-sized and also very gharial-looking (like the giant ''Rhamphosuchus'' or the sea-dwelling ''Teleosaurus''), its family, the Dyrosaurids, was one of the three groups of crocodylomorphs that survived the meteor of 65 mya and made into the Mammal Age, together with the still-extant Eusuchians and the odd mammal-like Notosuchians (see below). But while notosuchians reached the Miocene (the epoch in which the first hominids evolved), dyrosaurs reached only the Eocene with kinds like ''Dyrosaurus'' and ''[[http://en.wikipedia.org/wiki/Phosphatosaurus Phosphatosaurus]]''. The dyrosaurs' and notosuchians' natural history recalls the one of the last Champsosaurs (croclike diapsid reptiles), which got extinct in the Miocene.
335
336----
337
338'''When Crocs felt like becoming Fish'''
339
340* Initially, crocodiles were land animals. Then, many of them became amphibious, as they still are today. But some of them went even further, trying to colonize open seas. Here, they have always had trouble, because of the strong competition with the classic sea reptiles ([[UsefulNotes/StockDinosaursNonDinosaurs ichthyosaurs, plesiosaurs, mosasaurs]]). But a group of them did manage to coexist with the latter: the mainly Jurassic [[http://en.wikipedia.org/wiki/Thalattosuchia Thalattosuchians]] (literally "sea crocodiles", once classified within the "mesosuchian" suborder, see the note in the "supercroc" paragraph above). The most-archaic ones were still gharial-like and partially terrestrial, the most known being ''[[UsefulNotes/StockDinosaursNonDinosaurs Teleosaurus]]'' portrayed in the Crystal Palace Park in London, and the very similar ''[[http://en.wikipedia.org/wiki/Steneosaurus Steneosaurus]]''. The lesser-known ''[[http://en.wikipedia.org/wiki/Machimosaurus Machimosaurus]]'' was similar to the former two but one of its species (''M. rex'') reached 20 ft/7 m of length (like a modern saltwater crocodile), and is today the biggest known croc of the Jurassic -- but true supercrocs longer than 30 ft/10 m evolved only in the Cretaceous and beyond, in the Cenozoic Age. The most evolved marine crocodiles were the Metriorhynchids. They didn't even resemble crocs: rather, they looked like slender ichthyosaurs or small mosasaurs, because they developed the same identical ''caudal fins'' of an ichthyosaur, lost their armor altogether, and transformed their limbs in paddles (but still not true "flippers"). As a group the Thalattosuchians survived until Early Cretaceous, and among them there were probably the only fully-marine archosaurs ever. Maybe the metriorhynchids didn't even lay eggs and gave birth to alive newborn, just like ichthyosaurs and (perhaps) mosasaurs and plesiosaurs, but we have no proof of this. ''[[UsefulNotes/StockDinosaursNonDinosaurs Metriorhynchus]]'' and the ironically-named ''[[UsefulNotes/StockDinosaursNonDinosaurs Geosaurus]]'' ("''land'' lizard" or "[[Characters/ClassicalMythologyProtogenoi Gaia]] lizard") are the two most portrayed examples, and the respective prototypes of the two subfamilies of metriorhynchids, the slender long-snouted Metriorhynchines and the more robust Geosaurines. The recently-discovered ''[[http://en.wikipedia.org/wiki/Dakosaurus Dakosaurus]]'', a geosaurine, was an especially bizarre example as it possessed a theropod-like skull and teeth, earning it the nickname "Franchise/{{Godzilla}}". Another prehistoric reptile whose name was inspired by a Kaiju is the Triassic theropod ''[[UsefulNotes/PrehistoricLifeOtherSmallTheropods Gojirasaurus]]''.
341
342----
343
344'''A Whale of a Crocodile:''' ''[[http://en.wikipedia.org/wiki/Stomatosuchus Stomatosuchus]]''
345
346* One of the strangest and most specialized crocodilians ever, its name means "mouth croc": it was basically the crocodilian equivalent of the pterosaur ''Pterodaustro''. With its small teeth, ''Stomatosuchus'' lived probably upon plankton or other small organisms of the waters it lived within. Unlike the smallish ''Pterodaustro'', ''Stomatosuchus'' was big, almost as big as the famous "supercrocs" mentioned above. ''Stomatosuchus'', despite its large size (10 m or so) was a sort of ducklike or whalelike crocodylomorph, because its wide but weak jaws bear small crammed teeth maybe apt to an inoffensive filter-feeding. This odd prehistoric crocodilian lived in Late Cretaceous Egypt, and could maybe have met ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Spinosaurus]]'' in RealLife. If so, the two probably coexisted peacefully thanks to their different ecological niches, with bigger water food items for the spinosaur. Another infinitively smaller crocodilian (70 cm of length) whose wide flat jaws recalled those of a duck was ''[[http://en.wikipedia.org/wiki/Anatosuchus Anatosuchus]]'', aptly "duck-crocodile". This one was a notosuchian (see "Crocs that pretended to be mammals") that lived in Cretaceous South America, described in 2003.
347
348----
349
350'''...and Normal Crocs aren't only a XXI-Century Thing:''' ''[[http://en.wikipedia.org/wiki/Goniopholis Goniopholis]]''
351
352* Most known crocodylomorphs had the suffix ''-suchus'' on their name (meaning "croc" in Greek), but this isn't always the case -- after all, not every dino ends in ''-saurus'', not every prehistoric mammal ends in ''-therium'', and not every pterosaur ends in ''-dactylus''. And don’t forget that most prehistoric freshwater crocodylomorphs were not bigger than ours, either. The Late Jurassic/Early Cretaceous ''Goniopholis'' is one of the best-known examples, and was not bigger than a modern alligator or caiman. It was closely related with the Eusuchians (aka the "modern" crocodilians), and lived alongside ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Iguanodon]]'' among the others. The same about ''[[http://en.wikipedia.org/wiki/Bernissartia Bernissartia]]'', a tiny (only 2 ft/60 cm long) relative of ''Goniopholis'' whose name is due to being discovered in the famous Belgian coal mine in which the 40 Iguanodons described by Dollo were found. ''[[http://en.wikipedia.org/wiki/Allodaposuchus Allodaposuchus]]'' was an archaic true eusuchian like ''Deinosuchus'' but much smaller (10 ft/3 m long), that lived in the islands of the Late Cretaceous Europe together with several dwarf dinosaurs. Among Cenozoic crocodilians, ''[[http://en.wikipedia.org/wiki/Diplocynodon Diplocynodon]]'' ("double dog-tooth") was equally widespread in Europe: only 4 ft/1.2 m long, was virtually identical to a modern alligator or caiman. Despite its name, it was not related with the pre-dinosaur mammal-ancestors named the Cynodonts and the Dicynodonts.
353
354----
355
356'''Primeval Crocodile:''' ''[[http://en.wikipedia.org/wiki/Protosuchus Protosuchus]]''
357
358* And now, let's discover the opposite end: the smallest crocodylomorphs ever lived were land-loving, long-legged, agile things with a bit of dinosaur inside. Early Jurassic ''Protosuchus'' ("first croc", not to be confused with the Early Triassic "thecodont" ''[[UsefulNotes/StockDinosaursNonDinosaurs Proterosuchus]]'', also meaning "first croc") has been perhaps the most portrayed, and was found by the same discoverer of ''Tyrannosaurus rex'', Barnum Brown; closely related with ''Protosuchus'' (family Protosuchids) were the equally early-Jurassic ''[[http://en.wikipedia.org/wiki/Orthosuchus Orthosuchus]]'', that lived in Southern Africa, and the younger ''[[http://en.wikipedia.org/wiki/Hoplosuchus Hoplosuchus]]'', the latest one living in Late Jurassic USA together with many famous dinosaurs. ''Protosuchus'' has given its name to the Protosuchians, aka the traditional and artificial assemblage of the most primitive crocodylomorphs. It was very different from the earlier ''Proterosuchus'' despite the similar names: while this one was a big, primitive archosaur-relative living before the first dinosaurs appeared (roaming the landscapes together with mammal-ancestors like ''Cynognathus'' or ''Lystrosaurus''), ''Protosuchus'' was a small animal: 3 ft/1 m long, smaller than an adult human, and living together with the first large theropods like the 6 m long ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Dilophosaurus]]'' or basal sauropod predecessors like ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Anchisaurus]]''. ''Orthosuchus'' was even smaller, 2 ft/60 cm long, and lived alongside the medium-sized prosauropod ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Massospondylus]]'' and the tiny basal ornithischians ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Heterodontosaurus]]'' and ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Lesothosaurus]]'', which were both ''bigger'' than it. ''Protosuchus'' and ''Orthosuchus'' actually were more similar in look to small armored monitor-lizards than to a modern crocodilian (except for their unmistakable croclike skull and teeth), and they could have even been prey for small carnivorous dinosaurs like ''[[UsefulNotes/PrehistoricLifeOtherSmallTheropods Megapnosaurus]]'' other than for ''Dilophosaurus'': exactly like the basal ornithischians above, which were actually more agile than the protosuchids and sometimes more weaponed than them (the "canines" of the heterodontosaurs).
359
360----
361
362'''Tiny Bipedal Crocodile:''' ''[[http://en.wikipedia.org/wiki/Hallopus Hallopus]]''
363
364* Most land crocodylomorphs weren't related to each other however: several croc lines reached this body plan independently. Among the Jurassic and Cretaceous ones, the tiny [[http://en.wikipedia.org/wiki/Atoposauridae Atoposaurids]] were not bigger than a cat (50 cm of length at the most), and among the smallest crocs ever. Two of them have misleading names: ''Alligatorium'' and ''Alligatorellus'' had not to do with our powerful alligators, and looked more like common lizards at a first glance, being long-legged, with slim body, reduced armor, long neck, and small skull. It's simple to understand why so many "land-crocs" remained small: competition from dinosaurs was too strong in dry land, and they could survive only occupying the niche of small, fast-reproducing hunters, just like proto-mammals which shared the same niche. Some scientists hypothesize that the nocturnal adaptations mammals underwent during the Mesozoic (inherited by all modern mammals, even the diurnal ones like humans) were not determined by dinosaurs' predation, but rather by the competition of the (arguably) diurnal land crocs. Some of the latter were even partially bipedal: for example the Late Jurassic North American 3 ft long ''Hallopus'', which was smaller than ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Compsognathus]]''. ''Hallopus'' was found during the Bone Wars and, significantly, was originally believed a tiny ''dinosaur'', more precisely a species of the small ornithischian ''[[UsefulNotes/PrehistoricLifeHadrosaurPredecessors Nanosaurus]]''.
365
366----
367
368'''Crocs that pretended to be Mammals'''
369
370* Some land crocs became larger however, especially in Cretaceous South America and Australia, and were powerful predators in competition with theropod dinosaurs. Most of the land crocodylomorphs of this paragraph were part of the suborder [[http://en.wikipedia.org/wiki/Notosuchia Notosuchia]] (outside the Eusuchians), or were otherwise related to them. Some of them were almost mammal-like. While mammals hid in the dinosaurs' shadows, the croco-mammals were actively competing with them, at times growing to enormous sizes that directly competed with theropod dinosaurs and mammals; some species may have even driven them out of their own niches. They were also highly diverse; with the cat-like ''[[http://en.wikipedia.org/wiki/Pakasuchus Pakasuchus]]'' (whose name even translates into "cat crocodile"), the omnivorous short-nosed ''[[http://en.wikipedia.org/wiki/Simosuchus Simosuchus]]'' ("blunt crocodile"), the herbivorous ''[[http://en.wikipedia.org/wiki/Chimaerasuchus Chimaerasuchus]]'' ("chimaera crocodile"), the sabre-toothed ''[[http://en.wikipedia.org/wiki/Kaprosuchus Kaprosuchus]]'' ("boar-crocodile" because of its tusklike protruding teeth), the [[ExactlyWhatItSaysOnTheTin armadillo]]-like ''[[http://en.wikipedia.org/wiki/Armadillosuchus Armadillosuchus]]'', the pig-like ''[[http://en.wikipedia.org/wiki/Notosuchus Notosuchus]]'' ("southern crocodile"), and the [[NamesToRunAwayFromReallyFast hyperpredator]] ''[[http://en.wikipedia.org/wiki/Baurusuchus Baurusuchus]]'', which even dethroned the theropods as top predator. Not only did they successfully compete with dinosaurs for over 35 million years, they actually ''outlived'' them: the last forms did not die out until the Middle Miocene only 11 million years ago. From Paleocene/Eocene South-America, for example, come the fossils of the short-named ''[[http://en.wikipedia.org/wiki/Sebecus Sebecus]]''. One of the largest and youngest relatives of ''Sebecus'' was ''[[http://en.wikipedia.org/wiki/Barinasuchus Barinasuchus]]'', also South-American. The latter lived and competed with the giant flightless predatory birds named [[UsefulNotes/StockDinosaursSaurischianDinosaurs phorusrhacids]] (the "terror birds") and the largest carnivorous marsupial-like mammals like the "pseudo-sabertoothed cat" ''[[UsefulNotes/StockDinosaursNonDinosaurs Thylacosmilus]]'', and could have encountered the biggest known flying bird ever, the "giant vulture" ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Argentavis]]''. Probably the arrival of the evolved placental mammals from North America (the Great Pliocenic Interchange) deleted the last land crocs of South America.
371
372----
373
374'''Hoofed Crocodile:''' ''[[http://en.wikipedia.org/wiki/Pristichampsus Pristichampsus]]''
375
376* One of the most extreme examples known of a running croc appeared just after the mass extinction (that wiped out most crocodylomorphs as well): the large, "hoofed" ''Pristichampsus'' ("saw croc"). This one was one of the top-predators within its Early Cenozoic world (together with giant constrictor snakes like ''[[UsefulNotes/StockDinosaursNonDinosaurs Titanoboa]]''), populated mostly by much smaller creatures. Many of its alleged fossils are now attributed to another genus, ''[[http://en.wikipedia.org/wiki/Boverisuchus Boverisuchus]]''. This one was similar to ''Pristichampsus'', and lived alongside the large ground bird ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Gastornis]]'' and the big herbivorous hippo-like mammal ''[[UsefulNotes/StockDinosaursNonDinosaurs Coryphodon]]''. These two animals, in spite of being herbivorous or omnivorous, were massive and powerful enough to defend themselves well against these land-crocs when adults. Their calves/chicks, however, could have fallen prey to them because of their smaller size.
377
378----
379
380'''Crocs of Oceania:''' the [[http://en.wikipedia.org/wiki/Mekosuchinae Mekosuchines]]
381
382* The last group of crocs to take to the land was the Mekosuchines: they were a group of Eusuchians typical of Oceania, traditionally believed a subfamily of the modern true crocodiles (Crocodylids), but they could not be such. They were nonetheless closer to the crocs & gharials than to the gators & caimans. They were very diversified: some were large land predators like Australian ''[[http://en.wikipedia.org/wiki/Quinkana Quinkana]]'' (contemporary to the giant lizard ''[[UsefulNotes/StockDinosaursNonDinosaurs Megalania]]'' and one of its rival predators), others were small and some perhaps even tree-climbers! Mekosuchines lived across the Mammal Age, but the last kinds were wiped out by humans, first in Australia and much later in the Vanuatu and New Caledonia archipelagos of the Pacific Ocean -- maybe even in historical time in the latter island, but before the first European settlers managed saw the animals alive.
383
384----
385
386[[/folder]]
387
388[[folder:Turtles]]
389
390----
391
392'''An Even More Enduring Success'''
393
394* Turtles have ''literally'' been among the longest-lived reptiles ever, since appeared 230 million years ago and are still living today. But their origin has long been shrouded in mystery, with recent genetic analysis confirming that they are most closely related to crocodilians and birds of the clade Archosauria. The very first turtles ever discovered, among them ''[[http://en.wikipedia.org/wiki/Proganochelys Proganochelys]]'' (also called ''Triassochelys'') from [[ExactlyWhatItSaysOnTheTin the Triassic]], had already the classic turtle shape, shell and toothless beak included; since then, they have not changed their body plan at all for 250 million years. Mesozoic turtles were ''very'' similar to ours. They have had a great success, colonizing all three main habitats just like crocs, terrestrial, marine, freshwater (but unlike crocs they frequent all these environments still today); however, like crocs, freshwater has been the favourite one, while terrestrial and seagoing species have always been a minority.
395
396----
397
398'''Gigantic Shells'''
399
400* Marine turtles reached gigantic sizes in the Cretaceous: the famous ''[[UsefulNotes/StockDinosaursNonDinosaurs Archelon]]'' was 20 ft long and weighed ''several tons'': the contemporaneous ''[[http://en.wikipedia.org/wiki/Protostega Protostega]]'' ("first roof", the prototype of the archelon's family, Protostegids) was very similar to it and not much smaller, while the more obscure ''Calcarichelys'' was pretty small (about one foot in length) but developed a spiny shell to defend it against predators, like some modern freshwater turtles. Chelonians or Testudines (the correct names for turtles/tortoises) were the ''only'' group of Mesozoic sea reptiles which managed to survive the K-Pg mass extinction: unlike saltwater crocs, venomous sea-snakes, and Galapagos marine iguana (which returned in the sea during the Mammal age), modern marine turtles do descend from some ancestors already present before the cataclysm happened, though not from ''Archelon'' or ''Protostega'' which went eventually extinct without leaving descendants. The fossil record of chelonians is extremely abundant (like that of crocodilians and unlike those of lizards and snakes) since freshwater aid the fossilization, and hard-boned shells / bony armors do preserve very well. Most non-marine turtles were small, just like today, but the freshwater-dweller ''[[http://en.wikipedia.org/wiki/Stupendemys Stupendemys]]'' ("wonderous turtle") reached 3 m and was perhaps the biggest turtle that ever lived - rivalling the famous ''Archelon''. Astonishingly, it lived only 6 million years ago, not much before the first hominids. Much earlier (living just after the dinosaur extinction) was another large recently-discovered freshwater turtle, ''[[http://en.wikipedia.org/wiki/Carbonemys Carbonemys]]''. There were also two large land-living species just 1 million years before modern history: ''[[http://en.wikipedia.org/wiki/Megalochelys Megalochelys atlas]]'' (once "Testudo atlas" or "Colossochelys atlas"), the "Atlas tortoise" from India, was very Galapagos tortoise-like but ''as large as a small car''; the Australian ''[[http://en.wikipedia.org/wiki/Meiolania Meiolania]]'' (nicknamed "horned tortoise") was smaller but with a cooler look: it had [[ExactlyWhatItSaysOnTheTin small bovine-like hornlets]] on its head and an armored long tail, resembling a bit an ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Ankylosaurus]]'' or a ''[[UsefulNotes/StockDinosaursNonDinosaurs Glyptodon]]''.
401
402----
403
404'''Dinosaur Relatives?'''
405
406* Traditionally, turtles have been divided in three subgroups: the still-extant Cryptodirans (the typical turtles, living in land, freshwater & seas), the still-extant Pleurodirans (less-common today than once and typical of modern tropical freshwater), and the extinct "Amphichelids" (old artificial assemblage including the most basal chelonians). ''Archelon'', ''Protostega'' and ''Megalochelys'' were Cryptodirans, ''Stupendemys'' and ''Carbonemys'' were Pleurodirans, while ''Proganochelys'' was the classic "amphichelid". ''Meiolania'' was once believed a Cryptodiran, but today is considered a late-surviving "amphichelid", more basal than a cryptodiran or a pleurodiran. Note: not all Cryptodirans are/were able to retreat their head into the shell, while the Pleurodirans have the peculiarity to retreat their heads and necks ''laterally''. Extra-note: [[ScienceMarchesOn recent research]] seems to show turtles ''were not'' Anapsids as traditionally said, thus not descending from the "near-reptiles" (see the last folder of the page). Before that, they were believed the most ancient still living reptiles, but lizards and tuataras were perhaps more basal, and turtles (together with plesiosaurs) make probably the archosaur's sister-group: that is, they're closer to dinosaurs, including ''birds'', than to lizards & snakes, just like crocodiles. Recent fossils found in TheNewTens like ''[[http://en.wikipedia.org/wiki/Odontochelys Odontochelys semitestacea]]'' ("toothed turtle with half shell") belong to stem-turtles even more ancestral than ''Proganochelys'' itself, having ''true teeth'' and still incomplete shells. These "missing links" has connected turtles with Diapsids even more than the former genetic research made in the 2000s upon living species. A traditionally possible candidate for the "ancestor of turtles & tortoises" title has been ''[[http://en.wikipedia.org/wiki/Eunotosaurus Eunotosaurus]]'' because of the shape of its ribs, but this is not sure. In short, the real origin of turtles has been an age-old discussion among paleontologists. Everything Is Long-Living With Turtles, literally.
407
408----
409
410[[/folder]]
411
412[[folder:Lizards, Snakes & Sphenodonts]]
413
414----
415
416'''Dinos are not Lizards...'''
417
418* Contrary to turtles and crocodilians, lizards' fossil record is extremely poor: their gracile skeletons do not usually fossilize. Ironically, the best-preserved lizard remains known so far were discovered... into other creatures' rib cages. It's particularly famous the case of ''[[http://en.wikipedia.org/wiki/Bavarisaurus Bavarisaurus]]'', a small Jurassic lizard found into the first discovered ''Compsognathus'' skeleton. We don't know exactly which kind of modern lizards lived already in the Age of Dinosaurs: we're sure there were at least gecko-relatives like ''[[http://en.wikipedia.org/wiki/Ardeosaurus Ardeosaurus]]'', monitor-relatives like ''[[http://en.wikipedia.org/wiki/Estesia Estesia]]'', and "proto-iguanas" like ''[[http://en.wikipedia.org/wiki/Paliguana Paliguana]]'' (maybe only a lizard-relative); while chameleons seem to be a recent evolution, after the non-avian dinosaur extinction, derived from iguana-like ancestors. Lizards occupied the same niche ruled by mammals and the apparently similar land crocs, as small insectivores or omnivores. Today many groups of lizards are known: some are very rich of species, like the geckos (gekkonids and relatives), the skinks (scincids and relatives), the iguana-group (iguanids and relatives, among them the basilisks, the anoles, the horned lizards), the agamids (like the frilled lizard, the "thorny devil" and the "flying dragon"), and the common wall-lizards (lacertids). Other groups have less variety inside them but are very distinctive, like the chameleons (chamaeleonids), the monitors (varanids), the Gila "monsters" (helodermatids), the slow-worms and relatives (anguids), and the worm-lizards (amphisbaenians). The latest ones have often been considered apart from the other lizards (named collectively Saurians or Lacertilians) in classic taxonomy, due to their unique features.
419
420----
421
422'''Slurpasaurs'''
423
424* Many modern lizards are still compared with dinosaurs, or even passed off as "mini-dinosaurs", in documentaries and pop books; ironically, just because they were used in the past as a model for the early dinosaur paintings and models. This spread the popular notion that ''all'' prehistoric reptiles were nothing but "giant lizards": a notion then adopted by films, comics and whatnot, which has given to us the {{Slurpasaur}} trope. But lizards actually pertain to a ''very different'' group of reptiles than dinosaurs and even crocodiles (both archosaurs); this group is called the [[http://en.wikipedia.org/wiki/Squamata squamates]] (literally "the scaly ones"). Together with the sphenodonts (see below), squamates form in turn the Lepidosaurs. One may even hear the largest modern lizards ''literally'' passed off as dinosaurs in documentaries or other non-fictional works; the predestined victim is, obviously, the large monitor lizard called [[http://en.wikipedia.org/wiki/Komodo_dragon Komodo dragon]]. The astonishing thing is, our Indonesian "dragon" did have in the recent past a close Australian relative much, much larger than itself: ''[[UsefulNotes/StockDinosaursNonDinosaurs Megalania prisca]]'' (also known as ''Varanus priscus'') was 20 ft long, ''twice as long as its Komodo kin''; like its contemporary (this was a modern animal that lived with and was wipe out by humans) it was highly intelligent, as smart as most carnivorous mammals, was a fast runner, had shark-like teeth, produced venom, and lived ''just 50,000 years ago''. It was, arguably, one of the most powerful predators of its habitat. But don't forget the contemporary mekosuchine land croc ''Quinkana'', which was as big and as fast as the megalania, with equally strong teeth and the typical armored body of a crocodile (but lacking the venomous saliva), and ''Thylacoleo'', the [[UsefulNotes/StockDinosaursNonDinosaurs marsupial lion]]: though not larger than a lion, some scientists think this relative of kangaroos and koalas was the most efficient mammalian predator ever, maybe even capable to kill a fully-grown ''Megalania'' or ''Quinkana'' if it was lucky! ''Megalania'' is by far the largest lizard that ever lived. But wait... have we forgotten something? Yeah, the mosasaurs. It's so easy to forget this, but they ''were'' true lizards, and were distant relatives of the monitor lizards. They ranged in size from small 1 m/3.3 ft proto-mosasaurs like ''[[http://en.wikipedia.org/wiki/Opetiosaurus Opetiosaurus]]'' to giants like ''Mosasaurus'' and ''Tylosaurus'' that grew to more than 16 m/50 ft in total length and up to 10 tons of weight (approximately as heavy as a large male orca), the ultimate size-record belongs definitively to them. Along with ''Megalania'' and the Komodo dragon, mosasaurs are the only "giant lizards" which are TruthInTelevision. But wait… we've still forgotten something: yeah, anacondas and reticulated pythons, which can be 10 m/30 ft long and weigh up to 150/200 kgs. See below.
425
426----
427
428'''...Snakes are Lizards!'''
429
430* Snakes or Ophidians are the great exception among extant reptiles: they are a ''very'' recent thing, appearing only in the Late Cretaceous, just before the mass extinction. But their success was obtained only since the beginning of the Mammal Age 65 million years ago, and venomous species like the elapids (cobras, sea-snakes, and relatives) and the viperids (vipers, rattlesnakes, and relatives) appeared even later, 30-20 million years ago. The most ancient extant snakes are probably boas and pythons, or at least their closest relatives: the most common kind of snakes today, the colubrid snakes (grass snakes, rat snakes, and relatives), appeared in fully Cenozoic settings. The least-known among modern snakes, the small wormlike [[http://en.wikipedia.org/wiki/Scolecophidia blind snakes]] (typhlopids and relatives), are considered primitive like or more than the pythonids and the boids. Their resemblance with the equally poorly-known Amphisbaenians (earthworm-looking, usually limbless lizards) is coincidental, as the two groups of squamates are not closely related. Snakes today are very abundant: with more than 3,000 species they are the second biggest group of reptiles after birds. Among traditionally-intended "reptiles" only the non-snake/non-mosasaur squamates, aka the commonly-intended "lizards", have even more species (around 5,000). The turtles have today 300-400 species, the crocodilians less than 30 species, the tuataras only one. On the other hand, birds reach today a whopping ''10,000 species''. (twice as much as all modern mammal species combined, and roughly equivalent to the number of all extant non-avian reptile species combined).
431
432----
433
434'''The Reptiles of the Mammal Age'''
435
436* As birds are nothing but winged dinosaurs, snakes are nothing but legless lizards. Both birds and snakes diversified greatly only after the Great Extinction that divides the Reptile Age, the Mesozoic, from the Mammal Age, the Cenozoic. The Snakes (or more precisely the Ophidians) descend from a still unknown kind of Cretaceous lizard which did elongate its body losing the limbs at the same time. Curiously, the lizard group closer to snakes in phylogeny is not to be searched among the small slithering ones, like [[http://en.wikipedia.org/wiki/Anguis_fragilis slow worms]] or [[http://en.wikipedia.org/wiki/Amphisbaenia worm lizards]]. One hypothesis suggests snakes evolved from burrowing monitor-like lizards, or shared an ancestor with the gigantic mosasaurs instead, although recent genetic analysis and the discovery of ''[[http://en.wikipedia.org/wiki/Najash Najash]]'', a genus of two-legged snakes, is calling that relationship into question. The mosasaurs' reputation as the Cretaceous "sea serpents" is thus not totally unwarranted. Prehistoric snakes are not much portrayed in books or paleo art: this is probably because their remains are very, very scant, ''even more'' than those of their lizard ancestors: all that we often have are few isolated vertebrae, which don't allow to understand even how long they were. Hence, speculation and exaggerations tend to be common. ''[[http://en.wikipedia.org/wiki/Gigantophis Gigantophis]]'' (lit. "gigantic snake", which lived just after the dinosaur extinction) is a prime example: only known for fragmentary remains, it may get described as [[RuleOfCool twice the length of an anaconda]] despite it more probably was only a bit longer than the latter, if it was. If dealing with Cretaceous species, it'll probably be a ''[[http://en.wikipedia.org/wiki/Dinilysia Dinilysia]]'' ("terrible destroyer"). A very recent discovery, right after the extinction of non-bird dinosaurs, has been the 40-foot long, one-ton ''[[UsefulNotes/StockDinosaursNonDinosaurs Titanoboa]]'': its name means "titanic boa" for obvious reasons. ''Titanoboa'', despite being a recent discovery, has already shown up in a number of documentaries and even an episode of ''Series/PrimevalNewWorld''. Another interesting guy is ''[[http://en.wikipedia.org/wiki/Palaeophis Palaeophis]]'' ("ancient snake"), a marine boa that, like the aforementioned champsosaurs, survived the Cretaceous mass extinction and made it up to the Eocene. A real-life sea serpent, this creature has an estimated length of up to 30 feet, but is yet to be seen even in educational media. What about venomous snakes? Well, they never approached the size of the largest boas and pythons, but they still got impressively big. The largest venomous snake ever was ''[[http://en.wikipedia.org/wiki/Laophis Laophis]]'', a 13-foot [[note]]The biggest king cobras today are longer, but nowhere near as massive[[/note]] viper from what is now Greece. It was related to the Gaboon viper of Africa, which can swallow animals nearly its own size. If ''Laophis'' was like that, it could have taken prey the size of a small deer or a time-traveling human child!
437
438----
439
440'''We're almost Lizards'''
441
442* The [[http://en.wikipedia.org/wiki/Tuatara tuatara]] is the modern reptile more often cited for being a "living fossil", and with reason. It is the most ancient and primitive extant amniote (amniotes = reptiles + birds + mammals), a survivor which has miraculously managed to be alive today, while ''all'' its relatives went extinct before the end of the Mesozoic. The tuatara group is called the sphenodonts, a sibling group of the squamates. Traditionally called "rhynchocephalians", the sphenodonts' natural history is completely distinct to lizards and so on. They included, among the others, ''[[http://en.wikipedia.org/wiki/Homoeosaurus Homoeosaurus]]'', ''[[http://en.wikipedia.org/wiki/Clevosaurus Clevosaurus]]'', ''[[http://en.wikipedia.org/wiki/Planocephalosaurus Planocephalosaurus]]'', and ''[[http://en.wikipedia.org/wiki/Pleurosaurus Pleurosaurus]]''. One of the most ancestral was ''[[http://en.wikipedia.org/wiki/Gephyrosaurus Gephyrosaurus]]''. Sphenodonts are lepidosaurs just like lizards, but have retained more primitive traits still present in our tuataras; they appeared in the Triassic, like ''almost all'' the main reptilian lineages. Dinosaurs (both ornithischians and saurischians), pterosaurs, ichthyosaurs, plesiosaurs, crocodylomorphs, chelonians, lizards, even mammals: all these appeared in the Triassic. And sphenodontians as well. Like turtles, they didn't change much since then; fossils show that prehistoric tuataras were almost ''identical'' to their modern relative; and lived around the world, while they are limited only to New Zealand today. Like Komodo dragons, tuataras are often cites as "living dinosaurs" in pop-books. Once the "rhynchosaurs" (see "Triassic non-archosaurs") were considered early tuatara relatives (they are now considered closer to archosaurs): this explains why tuataras use to be called rhynchocephalians. The latter means "beaked head", and yet nobody'll ''ever'' see a tuatara with a beak! This term was actually referred to the parrot-billed rhynchosaurs, which were once considered rhynchocephalians as well. While "sphenodont" (former suborder Sphenodontoidea) has always been referred ''only'' to tuataras, ''never'' to rhynchosaurs: thus, the term sphenodont is more correct when referring to our spiky New Zealander and its ancestors.
443
444----
445
446[[/folder]]
447
448----
449
450'''Triassic Reptile Groups:'''
451
452[[folder:Triassic Archosaurs]]
453
454----
455
456In this field terminology has changed recently. Traditionally archosaurs were divided into dinosaurs, pterosaurs, crocodiles and [[http://en.wikipedia.org/wiki/Thecodontia thecodonts]], but the last name has fallen out of fashion as [[https://en.wikipedia.org/wiki/Paraphyly paraphiletic]] and is called by cladistics "artificial assemblage of basal archosaurs". Besides, only ''crown group'' (descendants of last common ancestor of birds and crocodiles, i.e. only living members) are called archosaurs, and others are Archosauriformes. Among thecodonts are the ancestors of crocs, dinos and pteros. Actually, some of them (''Teratosaurus'', ''Ornithosuchus'', and others) were once believed ''true dinosaurs'', precisely the very first large carnivorous dinosaurs, but most belong to the clade Pseudosuchia, today represented only by crocodilians. Basal archosaurs, often being somewhere between crocodylomorphs and dinosaurs, tend to get token appearances more in art and documentaries than anywhere else, and are rarely named.
457
458----
459
460'''Four-legged and Two-legged:''' The [[http://en.wikipedia.org/wiki/Rauisuchia Rauisuchians]]
461
462* The giant Rauisuchians are the most commonly represented Triassic archosaurs, as they were the apex predators of Late Triassic and the competition for the early dinosaurs. Rauisuchians (an artificial assemblage of archosaurs actually) were more related to crocodilians than to dinosaurs, but their look was more that of a small theropod rather than a crocodile, and their skull was very theropod-like. In fact, some of them, like ''Teratosaurus'' (below) and ''[[http://en.wikipedia.org/wiki/Zanclodon Zanclodon]]'' were long considered dinosaurs, often also because their remains were mixed with those of true dinosaurs like the contemporaneous "prosauropods". Today the 18 ft long ''[[UsefulNotes/StockDinosaursNonDinosaurs Postosuchus]]'' has become the new unofficial prototype of the group (the official one is ''[[http://en.wikipedia.org/wiki/Rauisuchus Rauisuchus]]''), especially after its memorable appearance in ''Series/WalkingWithDinosaurs'' as the competitor of ''Coelophysis''. Other rauisuchians, like the small European ''[[http://en.wikipedia.org/wiki/Ticinosuchus Ticinosuchus]]'' (which could have been the author of some footprints often cited in old textbooks as belonging to a quadruped named "[[http://en.wikipedia.org/wiki/Chirotherium Chirotherium]]") and the South American ''[[http://en.wikipedia.org/wiki/Saurosuchus Saurosuchus]]'' (lit. "lizard-crocodile", the biggest ever discovered, 25 ft long, not to be confused with ''[[UsefulNotes/StockDinosaursNonDinosaurs Sarcosuchus]]'', "meat-crocodile", that was a crocodylomorph of the Cretaceous) make one rauisuchian subgroup, the prestosuchians; another, very specialized subgroup is the poposaurs (below).
463
464----
465
466'''Crocs that pretended to be Dinos:''' The [[http://en.wikipedia.org/wiki/Poposauroidea Poposaurs]]
467
468* Poposaurs are perhaps the least known among the rauisuchians, but perhaps the more interesting. They were the most dinosaur-looking among all pseudosuchians (but until few years ago you'll read more often the name "Crurotarsan" for the archosaurs more closely related to crocs than to dinosaurs). Many of them were quadrupeds with sail backs resembling ''Dimetrodon'' (ex. ''[[http://en.wikipedia.org/wiki/Arizonasaurus Arizonasaurus]]''), and the most specialized were toothless and beaked (ex. ''[[http://en.wikipedia.org/wiki/Lotosaurus Lotosaurus]]''). Other were more theropod-looking, like the prototypical ''[[http://en.wikipedia.org/wiki/Poposaurus Poposaurus]]''. But the most surprising one are the bipedal or semibipedal shuvosaurids like ''[[http://en.wikipedia.org/wiki/Effigia Effigia]]'': if you take a look on them, you'll surely say they're [[UsefulNotes/StockDinosaursSaurischianDinosaurs ostrich-mimic dinosaurs!]] Controversial is the placement of ''[[http://en.wikipedia.org/wiki/Smok_(archosaur) Smok]]'' from Poland: it could be a rauisuchian, but also an early theropod. It lived alongside the huge mammal-ancestor ''[[UsefulNotes/StockDinosaursNonDinosaurs Lisowicia]]'' and perhaps hunted its cubs.
469
470----
471
472'''The Ancestor of the Carnosaurs?:''' ''[[http://en.wikipedia.org/wiki/Teratosaurus Teratosaurus]]''
473
474* ''Teratosaurus'': (“monster lizard”) lived in Europe during the Triassic period. Discovered as early as the middle of the XIX century, it was 6 m long, and has long detained the record of “the first giant meat-eating dinosaur”. In old books, ''Teratosaurus'' was portrayed as a generic-looking “carnosaur” which hunted the neighboring prosauropod ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Plateosaurus]]''. Then, in the mid-1980s, it was discovered that ''Teratosaurus'' wasn't a dinosaur at all. It was actually a non-dinosaurian archosaur related to ''[[UsefulNotes/StockDinosaursNonDinosaurs Postosuchus]]'', a member of a group that had convergently evolved to [[https://commons.wikimedia.org/wiki/File:Postosuchus_kirkpatricki.jpg resemble large theropods]].
475
476----
477
478'''Plant-eating, armored Crocodinos:''' The [[http://en.wikipedia.org/wiki/Aetosaur Aetosaurs]]
479
480* The only "thecodont" group that was entirely herbivorous (except for some poposaurs), with small jaws and teeth, aetosaurs looked like [[MixAndMatchCritter ankylosaurs crossed with crocodiles]]: they had a heavy armor covering not only their back but also ''their underbelly'', making them the most armored archosaurs that ever lived, even more than the ankylosaurs whose underbellies were like those of crocs, without a true armor (except small bony tubercles in some species). Like rauisuchians, aetosaurs reached large sizes (5 m the most) and had pillar-like limbs, but were surely quadrupedal like ankylosaurs - even though they could have lift themselves on their rear-legs, like many quadrupedal dinosaurs. Despite their upright limbs and their general appearance these animals were not dinosaurs, and their erect limbs were obtained by other means than those of dinosaurs. ''[[UsefulNotes/StockDinosaursNonDinosaurs Desmatosuchus]]'' is the most portrayed aetosaur, because [[RuleOfCool has one of the coolest-look among them]] with its long shoulder spikes surprisingly similar to those of certain ankylosaurs (the nodosaurids to be precise), and lived alongside ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Coelophysis]]'' in Triassic North America. ''[[http://en.wikipedia.org/wiki/Stagonolepis Stagonolepis]]'' and most other aetosaurs were devoid of these spikes and looked more like a stocky crocodile.
481
482----
483
484'''Croc-like Dinos or dino-like Crocs?:''' the [[http://en.wikipedia.org/wiki/Silesauridae Silesaurs]]
485
486* While many of the creatures above may superficially look dinosaurs, the only true basal archosaur related to dinosaurs (and pterosaurs) was the tiny ''[[UsefulNotes/StockDinosaursNonDinosaurs Lagosuchus]]'' and its relatives, called Dinosauromorpha. Among them the Silesaurids were especially diversified, and some deceptively resembled archaic ornithischian dinosaurs to the point that two of them, North-American ''Technosaurus'' and South-American ''Pisanosaurus'', were initially mistaken for Triassic ornithischians (today no ornithischian is surely known from Triassic, see UsefulNotes/PrehistoricLifePrimitiveOrnithischians). Together, dinosauromorphs and pterosaurs make one of the two main archosaur subgroups, the ornithodirans - literally "bird-necked", because many had [[ExactlyWhatItSaysOnTheTin flexible bird-like necks]], contrary to the almost always short-necked pseudosuchians (the other great archosaur subgroup). Only one foot long, ''Lagosuchus'' could stay on an adult man's hand without problems - hence its fanciful name, "[[KillerRabbit croc-rabbit]]"! It was a long, thin animal, a bit like a miniaturized ''Coelophysis'' but also capable to walk on all fours - complete bipedalism was reached only by its descendants, dinosaurs, thanks to the shape of their hips. However, ''Lagosuchus'' has been classified as a ''dinosaur'' in the past just because its dinosaurian appearance, but its skeleton is too primitive to make it a proper dinosaur. Lived in Triassic South America alongside the gigantic rauisuchian ''Saurosuchus'' and the very first ''true'' dinosaurs, such as ''Eoraptor'' and the herrerasaurians.
487
488----
489
490'''Bird-Crocodile:''' ''[[http://en.wikipedia.org/wiki/Ornithosuchus Ornithosuchus]]''
491
492* It's worth noting however, some partially bipedal croc relatives, such as ''Ornithosuchus'' and ''Saltoposuchus'' (both European and living alongside ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Plateosaurus]]''), were believed the real ancestors of dinosaurs because they too had a dinosaur-like appearance. Both animals are very common in old dino books: ''Ornithosuchus'' ("bird-crocodile") was 12 ft/4 m long and was once considered the ancestor of the "carnosaurs" (the big-robust theropods in the older meaning, see also UsefulNotes/StockDinosaursSaurischianDinosaurs); other less-known ornithosuchids include the South-American ''[[http://en.wikipedia.org/wiki/Venaticosuchus Venaticosuchus]]'' ("hunting croc") and ''[[http://en.wikipedia.org/wiki/Riojasuchus Riojasuchus]]'' ("La Rioja croc", not to be confused with the equally South American sauropodomorph dinosaur ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Riojasaurus]]'', also from Triassic).
493
494----
495
496'''Hopping Crocodile:''' ''[[http://en.wikipedia.org/wiki/Saltoposuchus Saltoposuchus]]''
497
498* The European ''Saltoposuchus'' ("foot-hopping crocodile") and North-American ''[[http://en.wikipedia.org/wiki/Hesperosuchus Hesperosuchus]]'' ("western crocodile") were much smaller (1 m long) and were once considered the common ancestor of dinosaurs, birds and crocodilians; they are actually simple crocodylomorphs. ''Hesperosuchus'' is possibly the real animal found in the famous ''Coelophysis'' specimen's braincase, that led the latter true dinosaur to be described as a cannibalistic eater of its own young in media. Then there's ''[[http://en.wikipedia.org/wiki/Scleromochlus Scleromochlus]]'' (also European), a tiny (only one foot long) animal that was also considered a proper dinosaur once, and could actually be the ancestor of the pterosaurs. ScienceMarchesOn has been a ''very'' common thing when coping with dinosaur ancestry.
499
500----
501
502[[/folder]]
503
504[[folder:Triassic Archosaur Relatives]]
505
506----
507
508As was stated in previous folder, some traditional thecodonts are no more called archosaurs through nothing has really changed in beliefs about their phylogeny (with exception of phytosaurs). Here they are:
509
510----
511
512'''The First Runners:''' the [[http://en.wikipedia.org/wiki/Euparkeriidae Euparkeriids]]
513
514* There were several archosaur offshoots as well in the Triassic. Some of them are closely related and very similar to the archosaurs above, and lived mainly in the Early Triassic (while true archosaurs were mainly Middle and Late Triassic): among them, the most iconic is surely ''[[UsefulNotes/StockDinosaursNonDinosaurs Euparkeria]]''. Discovered in South Africa in the Early Triassic, it was contemporary to the two stock cynodonts ''[[UsefulNotes/StockDinosaursNonDinosaurs Cynognathus]]'' and ''[[UsefulNotes/StockDinosaursNonDinosaurs Thrinaxodon]]''. This merely 3 ft long insectivore resembled a bit a theropod dinosaur in shape, but is thought to be only partially bipedal, and with slightly sprawling legs unlike dinosaurs and ''Lagosuchus'' above. ''Euparkeria'' has been perhaps the most commonly portrayed "thecodont" in classic sources, sometimes misinterpreted as "the first ancestor of dinosaurs" (like in ''Series/WalkingWithMonsters''). Once, it was also considered "the first animal that could walk on two legs"; but now [[ScienceMarchesOn it seems having lost this record]] in favor of the near-reptilian ''Eudibamus'' (see the last folder).
515
516----
517
518'''The High-Nosed Crocodiles:''' the [[http://en.wikipedia.org/wiki/Phytosaur Phytosaurs]] or Parasuchians
519
520* Phytosaurs have a very weird name: "[[IronicName plant lizards]]". A much more apt name for this group is Parasuchians, "near crocodiles". Phytosaurs indeed were the most crocodile-like among all Triassic reptiles, and occupied the freshwater predator niche outcompeting temnospondyl amphibians. But then, ''true'' crocodylomorphs took their place in turn, after the Triassic-Jurassic extinction event wiped the phytosaurs out.[[note]] The Chinese ''Pachysuchus'' was once considered an Early Jurassic parasuchian, but is most likely a sauropodomorph dinosaur.[[/note]] Phytosaurs could reach large size (5 m the most), but had very short limbs and long, thin jaws often similar to a modern gharial. However, it's easy separate them from crocs, by one feature: their nostrils were ''just in front of their eyes'', a bit like whales. Though once thought to be croc-line archosaurs (pseudosuchians), new analyses have shown that phytosaurs are likely outside of crown Archosauria altogether. ''[[UsefulNotes/StockDinosaursNonDinosaurs Rutiodon]]'' is one of the most portrayed, because it lived alongside ''Coelophysis'' and was a [[NeverSmileAtACrocodile potential predator]] of the latter.
521
522----
523
524'''The very first Crocodinos:''' the [[http://en.wikipedia.org/wiki/Proterosuchidae Proterosuchids]]
525
526* ''[[UsefulNotes/StockDinosaursNonDinosaurs Proterosuchus]]'' (not to be confused with the early Late Triassic crocodylomorph ''Protosuchus'') and its relatives were the first archosauromorphs which reached the mixed croc-dino shape of Triassic archosaurs. Indeed, proterosuchians may be the most basal thecodonts/archosauriformes. Also called [[Series/WalkingWithDinosaurs chasmatosaurs]] (nothing to do with the horned dinosaur ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Chasmosaurus]]'' except for their names, both meaning "cleft lizard"), they were medium-sized reptiles with long heads and croc-like shape, but had also a strange overbite which, along with the lack of armor and longer legs, made them distinctive. We don't know if they were semi-aquatic as usually stated: being so basal, they could still have been terrestrial.
527
528----
529
530'''Similarly-meaning Names:''' the [[http://en.wikipedia.org/wiki/Proterochampsidae Proterochampsids]]
531
532* Another croc-shaped group of basal archosauriforms is very rarely portrayed in books: the gharial-like proterochampsids. Interestingly, both ''Proterosuchus'' and ''[[http://en.wikipedia.org/wiki/Proterochampsa Proterochampsa]]'' mean "ancient crocodilian" (''champsa'' is another Greek word for crocs, other than the more familiar ''suchus''), but ''Proterochampsa'' seems to be more closely related to crown group. ''[[http://en.wikipedia.org/wiki/Archosaurus Archosaurus]]'' was a proterosuchid that interestingly bears the same name of the Archosaurs reptiles in general. Both the Proterochampsids and the Erythrosuchids (below) were also classified as proterosuchians until paraphyletic groups felt out of fashion.
533
534----
535
536'''The Crimson Crocs:''' the [[http://en.wikipedia.org/wiki/Erythrosuchidae Erythrosuchids]]
537
538* The most spectacular basal archosauriforms were the large, bulky, carnivorous ''[[UsefulNotes/StockDinosaursNonDinosaurs Erythrosuchus]]'', ''[[http://en.wikipedia.org/wiki/Shansisuchus Shansisuchus]]'', and their relatives: the erythrosuchians, lit. "red crocodiles". Nicknamed "[[FanNickname crimson crocs]]", with their one-meter long head (as large as an allosaur head) filled with robust teeth and with forward-facing eyes like a tyrannosaur, they occupied the top predator niche in the Early Triassic, substituting the mammal-like gorgonopsians (see further). However, they were stocky and armor-less animals arguably slower-moving than the more evolved rauisuchians, and finally get replaced by the latter in Late Triassic. Unfortunately, erythrosuchians didn't appear in any piece of the [[Series/WalkingWithDinosaurs Walking With]] TV series.
539
540----
541
542[[/folder]]
543
544[[folder:Rhynchosaurs & Others]]
545
546----
547
548Note that while recent evidence indicates that plesiosaurs, placodonts, and turtles may be basal archosauromorphs like them, they are still in separate folders just for differentiation.
549
550----
551
552'''Triassic Triceratopses:''' the [[http://en.wikipedia.org/wiki/Rhynchosaur Rhynchosaurs]]
553
554* Even though unfairly forgotten by the ''Walking With'' TV series as well, rhynchosaurians are perhaps the most interesting basal reptiles from the Triassic. Indeed, they were the most successful groups of herbivores in this period, thanks to their parrot-like beak (their name means "beaked lizards") and powerful grinding jaws which allowed them to chew even the toughest vegetation, as efficient as ceratopsian jaws. Rhynchosaurs owe their name from ''[[http://en.wikipedia.org/wiki/Rhynchosaurus Rhynchosaurus]]'', the first described kind. Like horned dinosaurs, they were four-legged, plant-eating reptiles with a bulky body and relatively short tail, but lacking any "horn". They were only distant archosaur relatives; once they were thought to be in the same group of the modern tuatara (see above). Rhynchosaurs were rather small compared to other Triassic reptiles, lived worldwide, and shared their habitat with the very first dinosaurs such as ''Plateosaurus'' and ''Coelophysis''. In the Middle Triassic they became the most successful land herbivores in the whole planet, and were perhaps the favorite prey for the first carnivorous dinosaurs like ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Herrerasaurus]]''. They went to extinction only at the end of the Triassic (like rauisuchians and the other basal archosaurs above) probably outcompeted by the first plant-eating true dinosaurs. ''[[UsefulNotes/StockDinosaursNonDinosaurs Hyperodapedon]]'' (also known as ''Scaphonyx'': once the two were considered two distinct animals) is the most portrayed rhynchosaur. It had a [[MixAndMatchCritter very bizarre look]]: its head was flat, its upper bill had a deep slit which served to accommodate the lower bill like in a Swiss Knife, and its eyes pointed ''forwards'' like an owl -- remember herbivores have usually lateral eyes to see nearly at 360 degrees: primates and sloths are among the rare exceptions.
555
556----
557
558'''Rhynchosaur Cousins:''' ''[[http://en.wikipedia.org/wiki/Shringasaurus Shringasaurus]]'' & ''[[http://en.wikipedia.org/wiki/Trilophosaurus Trilophosaurus]]''
559
560* Other than the rhynchosaurs, in the Triassic there were other terrestrial herbivorous archosauromorphs. One of the most classic is ''Trilophosaurus'' ("three-crested lizard", nothing to do with ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Dilophosaurus]]'' "two-crested lizard"), similar to a rhynchosaur but with a round beak. Especially worth noting is the recently-discovered (2014) ''Shringasaurus''. This one was 3-4 m long, had a head similar to a bull with two small "horns", and longer forelimbs than hindlimbs, resembling a cross between a bull and a lizard -- a bit like the famous horned bipedal theropod ''[[UsefulNotes/StockDinosaursSaurischianDinosaurs Carnotaurus]]''.
561
562----
563
564'''Triassic Brontosaurs:''' ''[[http://en.wikipedia.org/wiki/Dinocephalosaurus Dinocephalosaurus]]'' & ''[[http://en.wikipedia.org/wiki/Macrocnemus Macrocnemus]]''
565
566* Living in Triassic Europe, ''[[UsefulNotes/StockDinosaursNonDinosaurs Tanystropheus]]'' was one of the most enigmatic among all prehistoric reptiles. 15 ft long, its body was lizard-like but its neck was the longest respect-to-the-body that any creature known (even more than [[UsefulNotes/StockDinosaursSaurischianDinosaurs sauropods]] or ''[[UsefulNotes/StockDinosaursNonDinosaurs Elasmosaurus]]''), to the point it almost challenges physical laws. We haven't any precise idea how ''Tanystropheus'' lived: but it was almost certainly a partially aquatic creature. Its neck was particularly stiff, having only few very elongated vertebrae: since its neck was flexible only at the base, some hypothesized ''Tanystropheus'' used it as a fishing-rod for catching fish from ashore. Indeed, the neck vertebrae of ''Tanystropheus'' are so different-looking than the other vertebrae, the scientist who first described the animal though the neck and the remaining body were from [[MixAndMatchCritter two completely different animals]]! Interestingly, recent research has shown sauropods and even plesiosaurs too had stiff necks despite their higher number of neck vertebrae: this would make the comparison between ''Tanystropheus'' and sauropods/plesiosaurs rather apt. In the early 2000s, a close relative of ''Tanystropheus'' was found. Called ''Dinocephalosaurus'' ("terrible-headed lizard"), this reptile probably sucked in fish like a vacuum. But ''Tanystropheus'' and ''Dinocephalosaurus'' are only highly specialized members of their own group of basal non-archosaurs: the Prolacertiforms or Protorosaurs. Most of them were small and more lizard-like than their specialized cousins: ex. the namesakes ''[[http://en.wikipedia.org/wiki/Prolacerta Prolacerta]]'', ("before-lizard") and ''[[http://en.wikipedia.org/wiki/Protorosaurus Protorosaurus]]'' ("first lizard", not to be confused with the ceratopsid ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Torosaurus]]''). both were rather lizard-like but with very long hind limbs and also quite elongated necks. ''Macrocnemus'', also lizard-like, means indeed "long shin-bone". Another prolacertiform or protorosaur was small but very specialized and unmistakable: ''Sharovipteryx'', which looks very similar to and has similar adaptions to the gliding reptiles mentioned in the next section.
567
568----
569
570[[/folder]]
571
572[[folder:Gliding Reptiles & Others]]
573
574----
575
576'''Protruding Ribs, Flaps of Skin, and Pseudo-Wings:''' The "Gliding Lizards"
577
578* Even though are often nicknamed "gliding lizards", these reptiles ''were not'' lizards. They were small and lizard-shaped nonetheless, except for one thing: they were able to ''glide'', just like a modern lizard species called "[[http://en.wikipedia.org/wiki/Flying_dragon flying dragon]]". They weren't related to each other, and adopted several different gliding structures and mechanisms: North American ''[[http://en.wikipedia.org/wiki/Icarosaurus Icarosaurus]]'' ("[[Myth/GreekMythology Icarus]] lizard") and European ''[[UsefulNotes/StockDinosaursNonDinosaurs Kuehneosaurus]]'' (once called Eolacertilians, "dawn lizards", and closely related to true lizards and tuataras) had elongated ribs which sustained a skin membrane acting as a parachute, just like that of the "flying dragon"; Asian ''[[http://en.wikipedia.org/wiki/Sharovipteryx Sharovipteryx]]'' (originally called "Podopteryx" but the name was already in use for a modern dragonfly genus) had membranes extending from limbs to the body, in a way rather similar to pterosaurs. Some thought ''Sharovipteryx'' was the ''actual'' ancestor of pterosaurs, but this is not accepted anymore. While the most enigmatic of all, the hard-to-classify ''[[UsefulNotes/StockDinosaursNonDinosaurs Longisquama]]'' (its name means "long scale") had two rows of [[ExactlyWhatItSaysOnTheTin long scales]] protruding from each side of its body. However, nobody knows what these things exactly were (Real scales? Proto-feathers? Or a simple fossilization artefact as it seems according to recent research?) Despite this, ''Longisquama'' is perhaps the most portrayed "gliding lizard" in documentary media, and has even made an apparition in ''WesternAnimation/{{Dinosaur}}'', wrongly shown as an active flier capable to flap its "wings". Another "gliding lizard" appeared in ''Series/{{Primeval}}'': ''Coelurosauravus'' (see below).
579
580----
581
582'''Bird-headed Chameleons?:''' ''[[http://en.wikipedia.org/wiki/Drepanosaurus Drepanosaurus]]'' & ''[[http://en.wikipedia.org/wiki/Megalancosaurus Megalancosaurus]]''
583
584* Among the most basal diapsids - that is, the group containing all reptiles ''sensu stricto'' (except anapsids like ''Mesosaurus'' or ''Scutosaurus''), most looked like simple lizards, for example the Permian ''Araeoscelis'' and the Early Triassic ''Youngina''. But other were more specialized: the small tree-specialists avicephalans for example, also living in Early Triassic (nowadays the word 'avicephalan' is generally disused as it's probably contains unrelated animals). Some avicephalans were gliding forms similar to those already mentioned above: ex. the deceptively dinosaur-sounding ''[[UsefulNotes/StockDinosaursNonDinosaurs Coelurosauravus]]'' (literally "coelurosaur ancestor") had elongated ribs like those seen in ''Kuehneosaurus'' and ''Icarosaurus'', but was not related with them, being more primitive. It belonged to the Weigeltisaurids, from the very similar genus ''[[http://en.wikipedia.org/wiki/Weigeltisaurus Weigeltisaurus]]''. Another subgroup, the drepanosaurs, was more similar to chameleons but with a neck of a bird, ex. ''Megalancosaurus'' and ''[[http://en.wikipedia.org/wiki/Hypuronector Hypuronector]]''. Even though they are very rarely portrayed [[note]]One of them could have appeared at the start of WesternAnimation/TheLandBeforeTime original movie, but portrayed as a water-living creature: this would be ScienceMarchesOn, as originally ''Hypuronector'' was believed aquatic.[[/note]], drepanosaurs were among the most specialized and weird-looking reptiles ever; to give an example, ''Megalancosaurus'' had [[MixAndMatchCritter chameleon-like forearms, a bird-like beak, a large hump across its shoulders, and a prehensile tail with a claw at the end of it]].
585
586----
587
588'''Simple Lizards?:''' ''[[http://en.wikipedia.org/wiki/Araeoscelis Araeoscelis]]'' & ''[[http://en.wikipedia.org/wiki/Youngina Youngina]]''
589
590* It's worth noting that many basal diapsids that don't belong to any of the main reptilian groups were once put in their own group, the E'''o'''suchians ("dawn crocs", not to be confused with the E'''u'''suchians which are the ''real'' crocs). They were believed related with lepidosaurs, or lepidosaurs altogether: among former Eosuchians there are many animals mentioned in this folder, but also the aquatic thalattosaurians like ''Askeptosaurus'' and even the long-surviving croc-like champsosaurians. ''Araeoscelis'' and ''Youngina'' were both believed unspecialized basal eosuchians, in contrast with the specialized champsosaurs or thalattosaurs that were believed their descendants. This explains why in old textbooks is said that "the Eosuchians survived extremely long, from the Permian to after the Dinosaur extinction" (via champsosaurs).
591
592----
593
594[[/folder]]
595
596----
597
598'''Early Mammal-Ancestors:'''
599
600[[folder:Early Synapsids]]
601
602----
603
604This section talks about both "mammal-like reptiles" (not actually reptiles in a cladistic sense), and their descendants the Mesozoic mammals. However, if you're searching only for ''Dimetrodon'' and nothing else, see UsefulNotes/StockDinosaursNonDinosaurs.
605
606----
607
608'''When Mammals were still hairless "lizards"'''
609
610* We traditionally call "[[http://en.wikipedia.org/wiki/Pelycosaur pelycosaurs]]" the most basal synapsids (the correct name for the mammal-like "reptiles"), or in other words, non-therapsid synapsids. They were the dominant group of land animal in the Early Permian (for the record, the Permian period was ''just before'' the Mesozoic era), until they were replaced in the Middle Permian by their descendants, the therapsids. "Pelycosaurs" were still lizard-like in general body shape but showed already mammalian traits: their head was laterally flattened and high-settled above the ground, and their teeth started to show some resemblance with ours. By far the most popular are ''Dimetrodon'' and, to a lesser degree, ''[[UsefulNotes/StockDinosaursNonDinosaurs Edaphosaurus]]'', because both shared a similar crest (the so-called "sail") on their back sustained by elongated neural spines, still for uncertain purpose: a solar panel/radiator as traditionally said? A courtship device? Or both things? Most other "pelycosaurs" didn't have such a sail: these seem not to receive any attention, even in books. However, from little animals like the Carboniferous ''Archaeothyris'', several big, cool-looking animals originated, not only the sailbacks. The plant-eating ''[[http://en.wikipedia.org/wiki/Cotylorhynchus Cotylorhynchus]]'', for example, was not only the biggest pelycosaur known so far, but also one of the oddest-looking, with its [[MixAndMatchCritter disproportionately small head compared to the bulky body]]; the more normal-looking ''[[http://en.wikipedia.org/wiki/Ophiacodon Ophiacodon]]'' ("snake tooth") was one of the very first amniotes to reach large size (it was already living at the end of the Carboniferous); ''[[http://en.wikipedia.org/wiki/Varanosaurus Varanosaurus]]'' (literally "monitor lizard") and the similarly-named ''[[http://en.wikipedia.org/wiki/Varanops Varanops]]'' ("monitor face") were even earlier than the latter. While ''[[http://en.wikipedia.org/wiki/Sphenacodon Sphenacodon]]'' was a sort of sail-less ''Dimetrodon'', and gave its name to the Dimetrodon's family, Sphenacodontids, which includes also other "sailed" members such as the croc-headed ''[[http://en.wikipedia.org/wiki/Secodontosaurus Secodontosaurus]]''. The latter, because of its long slender jaws, had a weaker bite and arguably hunted smaller prey than the more robustly-skulled ''Dimetrodon''.
611
612----
613
614'''Scales or Hairs?'''
615
616* If you see old paleo art, expect to see ''scaly-skinned'' mammal ancestors. This is due to a long-standing TaxonomicTermConfusion: since they are classically called reptiles in Linnaean systematics, most old-fashioned artists use to draw them using actual modern reptiles as model. But horny scales are a exclusive thing of the diapsids aka true reptiles (and possibly anapsids aka near-reptiles). It's very unlikely that ''Dimetrodon'' and its kin developed horny scales only to lose them altogether after becoming mammals. On the other hand, modern birds still retain the old reptilian scales on their hind limbs... indeed, cladistically speaking, birds ''are'' true reptiles.
617
618----
619
620'''Horned Mammal-Ancestors?'''
621
622* Scientific names are often misleading. ''[[http://en.wikipedia.org/wiki/Tetraceratops Tetraceratops]]'', for example, means "four-horned face" but is ''not'' a middle-way between a ''Triceratops'' ("three-horned face") and a ''[[UsefulNotes/StockDinosaursOrnithischianDinosaurs Pentaceratops]]'' ("five-horned face"): it was a synapsid, thought by some a "missing link" between "pelycosaurs" and true therapsids, but with four small horns above of its head. ''Tetraceratops'' could actually belong to the most basal group of therapsids, the obscure Biarmosuchians, whose ''[[http://en.wikipedia.org/wiki/Biarmosuchus Biarmosuchus]]'' is the prototype. Only a bit more advanced was ''[[http://en.wikipedia.org/wiki/Eotitanosuchus Eotitanosuchus]]'': despite its name ("dawn titan-croc"), it was not related with the dinocephalian ''Titanosuchus'' (see just below).
623
624----
625
626[[/folder]]
627
628[[folder:Early Therapsids]]
629
630----
631
632'''Carnivores, Omnivores, and Herbivores:''' The [[http://en.wikipedia.org/wiki/Dinocephalia Dinocephalians]]
633
634* "[[http://en.wikipedia.org/wiki/Therapsid Therapsids]]" is the classic name for the most advanced mammal-like "reptiles"; cladistically speaking, however, it contains ''mammals'' as well, so we humans ''are'' therapsids in this sense. We'll use this term with the traditional meaning. It's worth noting that most therapsids have been discovered in two precise places in the world: South Africa and Russia. Dinocephalians ("terrible head") included the largest therapsids of the Paleozoic. They were bulky-bodied and large-headed, and lived in the Middle/Late Permian, but were wiped out by the Permian-Triassic extinction event. Some of these were herbivorous, like ''[[UsefulNotes/StockDinosaursNonDinosaurs Moschops]]'' and ''[[http://en.wikipedia.org/wiki/Tapinocephalus Tapinocephalus]]'' ("humble head"); and others were more likely carnivorous: ''[[http://en.wikipedia.org/wiki/Anteosaurus Anteosaurus]]'' [[note]]Anteus was a [[Myth/GreekMythology greek titan]]. [[/note]] and ''[[http://en.wikipedia.org/wiki/Titanophoneus Titanophoneus]]'' ("titanic murderer") or omnivorous (''[[http://en.wikipedia.org/wiki/Titanosuchus Titanosuchus]]'', meaning "titanic croc", and ''[[http://en.wikipedia.org/wiki/Jonkeria Jonkeria]]''). The meat-eating ones were the apex predators of the Middle Permian, but were later substituted by another therapsid group, the gorgonopsians. The most awesome-looking among dinocephalians is probably the Russian herbivore ''[[http://en.wikipedia.org/wiki/Estemmenosuchus Estemmenosuchus]]'' ("crowned croc"), with its bony, almost moose-like protrusions on its head whose purpose is uncertain. Despite their diversity, all dinocephalians shared common traits in their dentition. Curiously, ''Anteosaurus'' has often been depicted in drawings with a literal [[PantheraAwesome lion mane]] around its neck!
635
636----
637
638'''The Last Hunters before the Catastrophe:''' The [[http://en.wikipedia.org/wiki/Gorgonopsia Gorgonopsians]]
639
640* Recently popularized by ''Series/WalkingWithMonsters'' in the 2000s, gorgonopsians ("monstrous face") were the top predators of the Late Permian, but they too were deleted by the aforementioned mass extinction. More slender and usually smaller than dinocephalians, they are nicknamed "sabretooth" just like [[PantheraAwesome their mammalian namesakes]]; however their upper canines, though longer than most therapsids, were ''far less'' developed than those of a sabretooth-cat. The prototypical ''[[http://en.wikipedia.org/wiki/Gorgonops Gorgonops]]'', the wolf-sized ''[[http://en.wikipedia.org/wiki/Lycaenops Lycaenops]]'' ("wolf face", often shown hunting ''[[UsefulNotes/StockDinosaursNonDinosaurs Dicynodon]]'') and the similar-sized ''[[http://en.wikipedia.org/wiki/Sauroctonus Sauroctonus]]'' (portrayed in an old painting with the much bigger armored herbivorous near-reptile ''[[UsefulNotes/StockDinosaursNonDinosaurs Scutosaurus]]''), and the cow-sized ''[[UsefulNotes/StockDinosaursNonDinosaurs Inostrancevia]]'' (named after a Russian geologist, and perhaps the biggest of the group) are among the most portrayed. Gorgonopsians, ''[[UsefulNotes/StockDinosaursNonDinosaurs Cynognathus]]'' and other carnivorous therapsids are often described as [[AngryGuardDog dog-looking]]; indeed, in modern depictions, this resemblance is even more evident than in the older, more reptilian-like portraits.
641
642----
643
644'''From Mole-like to Elephant-like:''' The [[http://en.wikipedia.org/wiki/Dicynodont Dicynodonts]]
645
646* ''Dicynodon'' has given his name to the Dicynodonts, the most successful group of herbivorous therapsids. They appeared in Late Permian as small diggers such as the tiny ''[[http://en.wikipedia.org/wiki/Diictodon Diictodon]]'' ("two weasel teeth", portrayed in ''Series/WalkingWithMonsters''), ''[[http://en.wikipedia.org/wiki/Robertia Robertia broomiana]]'' (which honors Robert Broom, one of the greatest therapsid experts, who described in early XX century many South African mammal-ancestors), and the toothless ''[[http://en.wikipedia.org/wiki/Cistecephalus Cistecephalus]]''; flourished in the Early Triassic with ''[[UsefulNotes/StockDinosaursNonDinosaurs Lystrosaurus]]''; and then become bulky and vaguely elephant-like at the end of the Triassic: Russian/South African ''[[http://en.wikipedia.org/wiki/Kannemeyeria Kannemeyeria]]'' (named after Kannemeyer), Chinese ''[[http://en.wikipedia.org/wiki/Sinokannemeyeria Sinokannameyeria]]'' (meaning "Kannemeyeria from China" indeed), the Series/WalkingWithDinosaurs-famed North American ''[[UsefulNotes/StockDinosaursNonDinosaurs Placerias]]'' ("broad body"), and the gigantic Polish ''[[UsefulNotes/StockDinosaursNonDinosaurs Lisowicia]]'' (the biggest and last dicynodont known, the bulk of a small elephant, and the biggest non-mammal synapsid) are four main examples. Traditionally thought to have disappeared at the Triassic-Jurassic border, a recent discover seems indicating some Australian dicynodonts managed to make their way even in the Cretaceous. One thing does unify dicynodonts: their jaws. They had only ''two teeth'' at all, the upper canines vaguely {{Dracula}}-like, while the tip of their mouth was a sort of tortoise-like beak for cutting vegetation. Some species however lacked even these teeth, but still they made their way very well.
647
648----
649
650[[/folder]]
651
652[[folder:Advanced Therapsids]]
653
654----
655
656'''Very Mouse-Like:''' The last [[http://en.wikipedia.org/wiki/Cynodont Cynodonts]]
657
658* Not only the classic [[UsefulNotes/StockDinosaursNonDinosaurs carnivorous]] ''Cynognathus'' and ''Thrinaxodon'': the cynodonts were very diverse in habits. The closest-to-mammals were often not predatory at all: traversodonts (''[[http://en.wikipedia.org/wiki/Traversodon Traversodon]]'', ''[[http://en.wikipedia.org/wiki/Massetognathus Massetognathus]]'', and others), for example, were omnivores or even herbivores; tritylodonts (so-named from their prototype ''[[http://en.wikipedia.org/wiki/Tritylodon Tritylodon]]'') even developed rodent-like teeth for gnawing. However, both achieved their traits independently from modern herbivores, and were not direct ancestors of mammals. However, the last common mammal ancestor has surely to be searched among cynodonts. Tritylodonts were particularly close to mammals, while the Traversodonts were closer to ''Cynognathus'' than to mammals in the evolutive tree. In the Late Triassic, cynodonts were the only successful therapsid group: dicynodonts were still surviving but were rare at that point. Non-mammalian cynodonts survived until the Early Jurassic with two groups, the Tritylodonts like ''[[http://en.wikipedia.org/wiki/Oligokyphus Oligokyphus]]'', and the Ictidosaurs ("weasel-lizards") like ''[[http://en.wikipedia.org/wiki/Tritheledon Tritheledon]]''. Tritylodonts reached even the Early Cretaceous, with the [[SoleSurvivor enigmatic]] ''[[http://en.wikipedia.org/wiki/Xenocretosuchus Xenocretosuchus]]'' ("strange cretaceous croc"). But cynodonts sensu stricto made a minor part of the synapsid fauna after Triassic: their true mammalian descendants were dominant at this point.
659
660----
661
662'''A Great Unknown Epic'''
663
664* Non-mammalian synapsids were ''extraordinarily'' numerous in prehistory. More than 500 genera have been described so far, especially among the therapsids. The most abundant and diversified subgroups of therapsids were the Dinocephalians (''Moschops'' and kin), the Dicynodonts (''Lystrosaurus'' and kin), and the [[http://en.wikipedia.org/wiki/Theriodontia Theriodonts]] (meaning "mammal-tooth"). The last term is now usually in disuse (being probably paraphyletic) and indicates the more mammal-looking therapsids, like the relatively few gorgonopsians (all similar to each other) and the much more numerous & diversified cynodonts. Other subgroups of therapsids were very generic-looking and are usually ignored by paleo-artists: for example, the [[http://en.wikipedia.org/wiki/Anomodont basal anomodonts]], closely related with the dicynodonts (aka the advanced anomodonts) but more primitive. One example of non-dicynodontian anomodont was the multi-toothed, beakless and lizard-shaped ''[[http://en.wikipedia.org/wiki/Galepus Galepus]]'' ("weasel-foot"). There is still another numerous & diversified group of "theriodont" therapsids to be mentioned, considered the sister-group of the cynodonts: see below.
665
666----
667
668'''Obscure Relatives:''' The [[http://en.wikipedia.org/wiki/Therocephalia Therocephalians]]
669
670* Among the least portrayed among the main therapsid groups, therocephalians ("mammal-head") were similar in size and shape to the cynodonts, but less mammal-like, and only distantly related to mammals. Therocephalians began in the Permian and survived until the Early Triassic, but then were replaced by their more evolved relatives, cynodonts indeed. Just like the latter, they were initially carnivores (ex. ''[[http://en.wikipedia.org/wiki/Lycosuchus Lycosuchus]]'' "wolf-croc", and ''[[http://en.wikipedia.org/wiki/Pristerognathus Pristerognathus]]'', "saw-jaw"), but then some of the last forms became vegetarian (''[[http://en.wikipedia.org/wiki/Bauria Bauria]]'', once considered in a distinct group, the Bauriamorphs), while others became more similar to lizards (''[[http://en.wikipedia.org/wiki/Ericiolacerta Ericiolacerta]]'': "lacerta" just means lizard in Latin). One unidentified predatory therocephalian appears in ''Series/WalkingWithMonsters'', portrayed with a totally speculative venomous bite; it could be ''[[http://en.wikipedia.org/wiki/Euchambersia Euchambersia]]''.
671
672----
673
674!!Thank You Dinosaur! MESOZOIC MAMMALS
675
676----
677
678'''Milk, Hair, Limbs, Jaws & Ears'''
679
680* The boundary between mammals and non-mammals has always been a hard issue for paleontologists. Since typical mammalian features such as hair, milk glands, etc... do not fossilize most the time, the key to separate the two ensembles lays in their skull. True mammals have a mandible made by a single couple of bones, and ''three'' ossicles in the mid-ear. Non-mammalian synapsids have several pairs of bones in the lower jaw and a ''single'' ossicle in the ear. It's also worth noting that mammalian features probably didn't appear all in the same instant: perhaps some therapsids ''already'' produced milk and had hair, though they didn't have erect limbs yet, unlike modern mammals (except platypus and echidna, aka the Monotremes, that still have splayed limbs and primitive milk glands). Some quasi-mammals (more correctly called [[http://en.wikipedia.org/wiki/Mammaliaformes Mammaliaforms]]) began in Late Triassic and were tiny, very shrew-like, and insectivorous: ''[[http://en.wikipedia.org/wiki/Morganucodon Morganucodon]]'' and ''[[http://en.wikipedia.org/wiki/Megazostrodon Megazostrodon]]'' are the two most portrayed. Both were once classified as "triconodonts", but today this term only indicates some more evolved true mammals from the Jurassic and Cretaceous, like the cat-sized ''[[http://en.wikipedia.org/wiki/Triconodon Triconodon]]'' indeed. Another group of mammaliaforms were the omnivorous docodonts, which managed to reach the Late Jurassic with species such as the namesake ''[[http://en.wikipedia.org/wiki/Docodon Docodon]]''. The first true mammals (''Mammalia'') appeared in the early Jurassic, and were shrew-like just like their Triassic mammaliaform ancestors. They remained so for all the Mesozoic... [[ScienceMarchesOn at least this is what scientists used to think]]. Traditionally, fossils of Mesozoic mammals are extremely rare and fragmentary due to their smallness; but some very interesting new mammal fossils have been discovered since the TurnOfTheMillennium, and we now know mammals and even mammaliaforms were already very diversified at the Age of Dinosaurs. Some were mole-like diggers (''[[http://en.wikipedia.org/wiki/Fruitafossor Fruitafossor]]''), some were beaver-like swimmers (''[[http://en.wikipedia.org/wiki/Castorocauda Castorocauda]]''), and some were ''even'' gliders (''[[http://en.wikipedia.org/wiki/Volaticotherium Volaticotherium]]'').
681
682----
683
684'''Insignificant Critters?'''
685
686* If you'll read a paleo book you have good chance to see Mesozoic mammals/mammaliaforms described as [[MeekMesozoicMammal insignificant little creatures ruled by the mighty dinosaurs]]. Actually, thanks to their possibly dense populations, these synapsids could have affected their ecosystem the same way dinosaurs did; and remember that small animals are often key species in their natural environments. Another unexpected discovery from the 2000s showed Mesozoic mammals not being necessarily prey for dinosaurs as well: the badger-sized ''[[http://en.wikipedia.org/wiki/Repenomamus Repenomamus]]'' was discovered with [[EatsBabies baby dinosaur remains in its stomach]]. Another commonplace to debunk is that Mesozoic mammals were ''all'' insectivores. Actually, a whole group, the [[http://en.wikipedia.org/wiki/Multituberculata Multituberculates]] were rodent-like and herbivorous: their name "multi-tubercled tooth" is due to an unique couple of protruding cheek-teeth. They were the most abundant early mammals at the end of the Cretaceous, and managed to survive after the mass extinction. At the beginning of the Cenozoic they became even more successful, until true rodents replaced them in the Oligocene ([[https://www.cell.com/current-biology/fulltext/S0960-9822(21)00591-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982221005911%3Fshowall%3Dtrue or not]]). Multituberculates were the longest living mammalian group ever before gone extinct. One of the largest, ''[[http://en.wikipedia.org/wiki/Taeniolabis Taeniolabis]]'' from the Palaeocene, weighed 100 kg (the bulk of a giant panda). The direct common ancestor of modern mammalian groups (placentals, marsupials, and monotremes) is unknown, but all the three groups became widespread only in the Cretaceous, especially in Late Cretaceous. We can mention: the platypus-like ''[[http://en.wikipedia.org/wiki/Steropodon Steropodon]]'', an early monotreme belonging to a distinct lineage than the ones of true platypuses & echidnas, portrayed in ''Series/WalkingWithDinosaurs'' as a scavenger; the early otter-like "marsupial" ''[[UsefulNotes/StockDinosaursNonDinosaurs Didelphodon]]'', also portrayed in WWD as an opportunist; and the oddly-named placental ''[[UsefulNotes/StockDinosaursNonDinosaurs Purgatorius]]'', which is often considered the first known ancestor of primates, or at least, a close relative. Together, eutherian mammals (the placentals) and metatherians (the marsupials) make their own group: the [[http://en.wikipedia.org/wiki/Theria Therians]] (literally "the beasts" in Greek). Monotremes, on the other hand, are much more primitive than the former, and are traditionally called [[http://en.wikipedia.org/wiki/Prototheria Prototherians]] ("the first beasts"). You could also read the names "allotherians", "symmetrodonts", and "pantotherians" especially in older texts. [[http://en.wikipedia.org/wiki/Allotheria Allotherians]] ("the other beasts") included the multituberculates and their relatives; [[http://en.wikipedia.org/wiki/Symmetrodont Symmetrodonts]] ("symmetrical teeth") had three-pointed cheek-teeth, and the word still indicates a natural group of mesozoic mammals though more strict than formerly; "[[http://en.wikipedia.org/wiki/Pantotheria Pantotherians]]" ("the totally-beasts") included the common ancestors of marsupials and placentals. As you'll see in the following [[UsefulNotes/PrehistoricLifeMammals mammal section]], ''-therium'' is the common suffix for most extinct mammals, a bit like ''-saurus'' for extinct reptiles.
687
688----
689
690'''Dawn Parents'''
691
692* In the 2000s two animals discovered from the famous Early Cretaceous deposits of China were object of some sensationalism: ''[[http://en.wikipedia.org/wiki/Sinodelphys Sinodelphys]]'' the "first marsupial ever", and even more ''[[http://en.wikipedia.org/wiki/Eomaia Eomaia]]'' "the first ever placental" and thus "[[RuleOfCool the first Man's ancestor]]" ("Eomaia" meaning "dawn mother"). However, as mammal fossils from the Mesozoic are such a rarity, it's virtually impossible understanding which one was ''really'' the most basal placental / marsupial. Both are very precious, though, because they have preserved their fur -- before that, the oldest fossilized furs were from the Early Cenozoic (the famous Messel tar pits of Germany). Finally, let's debunk another tenacious myth about mammal evolution: we must thank if non-avian dinosaurs went extinct, otherwise humans couldn't have appeared on Earth. Maybe we could have appeared just the same, maybe a bit later... It's more probable that dinos actually ''guided'' mammal evolution in an indirect way. Being competitors of and preying upon our ancestors, they selected actively the most adapted, most evolved traits [[MostWritersAreHuman us mammals are proud of]]: among them, intelligence and parental care. If you are here to read this now, you have to thank dinosaurs. Everything has always been better with dinosaurs!
693
694----
695
696[[/folder]]
697
698----
699
700'''"Near-reptiles":'''
701
702[[folder:Mesosaurs, Pareiasaurs & Others]]
703
704----
705
706The animal listed here were once called "cotylosaurs", but this word is now fallen in disuse. This was a catch-all term for all most primitive "reptiles" which couldn't be placed in another well-defined groups. However, some of them still make a natural grouping: Anapsids. They were a successful group of animals which make a group on their own, intermediate between true reptiles (the diapsids) and the mammal-like synapsids: hence their alternate name: parareptiles ("near reptiles"). Most anapsids were even more ancient than diapsids: they lived mainly in the [[http://en.wikipedia.org/wiki/Permian Permian period]] alongside ''[[UsefulNotes/StockDinosaursNonDinosaurs Dimetrodon]]'' and the other mammal ancestors. Like therapsids, they were mainly discovered in Russia and South Africa. Whether turtles are just surviving anapsids or not has long been matter of discussion: today they're considered true diapsids, though still of uncertain placement in the tree (see “Extant reptile groups” above).
707
708----
709
710'''Near-Reptilian Tortoises:''' the [[http://en.wikipedia.org/wiki/Pareiasaur Pareiasaurs]]
711
712* Pareiasaurs were the only anapsids which reached great size, almost like a small rhinoceros at the extreme (but there were also smaller species though). They resembled a bit some plant-eating therapsids in shape (''Moschops'', ''Placerias'', ''Lisowicia''…), with their bulky frame, short tails, strong semierect limbs, and an armored skull. Indeed, pareiasaurs occupied their niche during the Late Permian, substituting dinocephalian therapsids (which were dominant in the Middle Permian); but were wiped out by the mass extinction and substituted in turn by other therapsids (the dicynodonts) and the non-therapsid rhynchosaurs in the Triassic. An early theory said pareiasaurs could have been the ancestors of turtles and tortoises. Now this seems disproved, as turtles’ anatomy is very specialized and very different to that of a pareiasaur. ''[[UsefulNotes/StockDinosaursNonDinosaurs Scutosaurus]]'' ("scute lizard") was one of the largest pareiasaurs and the most armored, with a "horned" skull and bony plates on its back (a sort of archaic version of an ankylosaur). Of course, [[RuleOfCool this is the pareiasaur most common in media]]. Other examples are the namesake ''[[UsefulNotes/StockDinosaursNonDinosaurs Pareiasaurus]]'' (as large as the former but armor-less), the more primitive ''[[http://en.wikipedia.org/wiki/Anthodon_(reptile) Anthodon]]'' ("flower tooth") and the small spiky ''[[http://en.wikipedia.org/wiki/Elginia Elginia]]'', with no armor-back but head horns like some ankylosaurs and the "horned tortoise" ''Meiolania''. ''[[http://en.wikipedia.org/wiki/Deltavjatia Deltavjatia]]'' was another basal pareiasaur. Pareiasaurian parareptiles were related more with the Procolophonoids (see further) than to the Mesosaurs (just below).
713
714----
715
716'''Near-Reptilian Crocodiles:''' the [[http://en.wikipedia.org/wiki/Mesosaur Mesosaurs]]
717
718* As already seen, the croc-like body plan was independently reached by several primitive extinct reptiles (phytosaurs, proterosuchians, champsosaurs...), and also by a group of near-reptiles, the Mesosaurs ([[TaxonomicTermConfusion do not confound them with mosasaurs!]]). They were among the most basal anapsids, but perhaps the most specialized. Semi-aquatic, they were a bit like unarmored gharials, with a croc-like shape and long jaws filled with strongly-crammed teeth. As these teeth look weak and needle-like, the mesosaurs’ diet is uncertain: they could have been either fishers or filter-feeders. Mesosaurs were small-sized (3 ft long) and arguably weren’t strong swimmers: they are known to be freshwater dwellers. However, their remains have been found in several Southern continents. Since they couldn’t be capable to cross open seas, they were used as a demonstration of the Pangaea hypothesis. In their time (Permian) continents were still linked together, and this allowed mesosaurs to go across landmasses with ease without leaving freshwater. ''[[UsefulNotes/StockDinosaursNonDinosaurs Mesosaurus]]'' ("middle lizard") and ''[[http://en.wikipedia.org/wiki/Stereosternum Stereosternum]]'' are among the best-known kinds in this group. Interestingly, the oldest currently known fossilized amniotic embryos [[http://www.tandfonline.com/doi/abs/10.1080/08912963.2012.662230 are mesosaur embryos]], and it seems that mesosaurs were the oldest group of amniotes known to evolve viviparity.
719
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721
722'''Near-Reptilian Lizards:''' the [[http://en.wikipedia.org/wiki/Procolophonoidea Procolophonoids]]
723
724* The most successful anapsids, however, were the procolophonids. They were the [[SoleSurvivor only]] anapsid group which managed to survive the awful mass extinction at the end of the Permian, and survived long enough to see the first dinosaurs; only the Triassic-Jurassic mass extinction deleted them definitively. ''[[http://en.wikipedia.org/wiki/Procolophon Procolophon]]'' found in South-Africa, Brazil and Antarctica (another proof of the Pangaea, just like the mesosaurs) lived in Late Permian/Early Triassic, is the namesake of the group, resembled an iguana in shape, and could have been omnivorous. One of the latest procolophonids was ''[[http://en.wikipedia.org/wiki/Hypsognathus Hypsognathus]]'', which developed spikes on its head convergently with some pareiasaurs. This animal lived alongside the earliest dinosaurs of Eastern North America. Similar to the true procolophonids but exclusively Permian were ''[[http://en.wikipedia.org/wiki/Nyctiphruretus Nyctiphruretus]]'' and ''[[http://en.wikipedia.org/wiki/Bolosaurus Bolosaurus]]''.
725
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727
728'''The First Biped?:''' ''[[http://en.wikipedia.org/wiki/Eudibamus Eudibamus]]''
729
730* Most other anapsids had a very generic look, classically described as "lizard-like"; for example, the Middle / Late Permian Millerosaurs like the similarly-named ''[[http://en.wikipedia.org/wiki/Millerosaurus Millerosaurus]]'' and ''[[http://en.wikipedia.org/wiki/Milleretta Milleretta]]''. Once considered anapsids, the Captorhinids like ''[[http://en.wikipedia.org/wiki/Captorhinus Captorhinus]]'' and ''[[http://en.wikipedia.org/wiki/Labidosaurus Labidosaurus]]'', from Middle and Early Permian, have revealed to be diapsid relatives; this has happened as well to another animal, ''Hylonomus'' (see just below). Finally, let's not forget the tiny anapsid ''Eudibamus'', described in 2000. Living at the start of the Permian period and related with ''Bolosaurus'', this is the guy which has taken over the title to the Triassic ''Euparkeria'' for being the first animal ever capable to run on two legs.
731
732----
733
734'''In The Coal Age'''
735
736* The very first amniotes appeared in the Carboniferous, the Paleozoic period with huge swamp forests populated by giant bugs and large amphibians. Traditionally we quote Carboniferous "reptiles" as "lizard-like" because were similar to 1 ft long lizards in shape, but some weren't even reptiles ''sensu stricto''. The most cited has been ''[[UsefulNotes/StockDinosaursNonDinosaurs Hylonomus]]'' ("law of the forest"), because it was long believed the most ancient of all; some hylonomes have been found inside fossilized logs so abundant in the Carboniferous. Another is ''[[http://en.wikipedia.org/wiki/Petrolacosaurus Petrolacosaurus]]'', which lived slightly after ''Hylonomus'' and was a full diapsid - contrary to the latter which was only a relative of diapsids. ''Walking With Monsters'' chose to show ''Petrolacosaurus'' as "the very first reptile": only.... [[ArtisticLicensePaleontology for some weird reason]], it magically reveals to be the ancestor of ''mammals'' in this show. This is even more unbelievable if you think that the ''true'' first known mammal ancestor ''was available'' for a Carboniferous setting: ''[[http://en.wikipedia.org/wiki/Archaeothyris Archaeothyris]]''. Put together, these three animals make the most archaic common ancestors of all land vertebrates that lived from Permian up to now (amphibians excluded, which originated before these and remain ''only partially'' terrestrial even today). Among their descendants there are indirectly birds and mammals as well, and thus ''mankind'' itself. Recently, in 1999, another Carboniferous animal has been described from Scotland, which could be the real first amniote: ''[[http://en.wikipedia.org/wiki/Casineria Casineria kiddi]]''.
737
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739
740[[/folder]]
741

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