Useful Notes / Prehistoric Life - Dinosaurs

Non-stock dinosaurs are really numerous, so it could be useful knowing the scientific history at least of the most prominent ones. Of course we shouldn't omit their more popular fellows, so you'll find also references to T. rex, Triceratops, and even some non-dinosaurs like Pteranodon in the folder below.

     Dinosaur history 

EARLY AND MIDDLE 1800: the first discoveries

In the 1801 France, in full Napoleonic age, Baron Georges Cuvier described the first "antediluvian reptile" note  found in Germany: the "Ptero-dactylo" — later re-named Pterodactylus by other scientists which chose to follow the Linnean convention to name animals with latin italicized names. Few years later Cuvier, who was the actual founder of Palaeontology, named the first marine reptile: the "mosasaur" (Mosasaurus), whose jaws were re-discovered in the Netherlands. These two creatures showed that before the "mammal era" populated by mammoths mastodons woolly-rhinos cave-bears megatheres and megaceres (already known since the late 1700) there was an era dominated by reptiles, named the "reptile era" indeed (what today is called the Mesozoic). But there weren't still dinosaurs. The first dinosaurs came to light about twenty years after the "ptero-dactylo".

  • In England

In the middle of the 1820s, the first giant carnivorous and the first giant herbivorous dinosaur were discovered in Southern England. Known mainly from their jaws and teeth, they were named Megalosaurus ("big lizard") and Iguanodon ("iguana tooth") by reverend and geologist William Buckland and medician Gideon Mantell respectively. Although not being professionistic palaeontologists both were aware to have discovered something new among prehistoric animals. Mantell in particular pointed that his Iguanodon was not a simple "giant lizard" (as its name would suggest): both the megalosaur's and the iguanodon' teeth were in sockets like those of crocodilians and mammals and unlike those of lizards, and the Iguanodon ones were worn, showing the animal actually chew its food, again like mammals and unlike iguanas.

When Mantell described the incomplete skeleton of a third large terrestrial reptile he named Hylaeosaurus armatus (armored lizard of the forest), it became clear that a whole fauna of huge land-reptiles shared the "reptile era" with the more-familiar-at-the-time pterodactyls and sea reptiles — whose typical representants were discovered before the first non-bird dinosaurs: Ichthyosaurus, Plesiosaurus and the pterosaur Dimorphodon were found in England in the 1810s by Mary Anning, joining Pterodactylus & Mosasaurus above.

When the father-of-paleontology Cuvier examined Buckland's and Mantell's fossils he initially didn't recognized them as dinosaurs, and (in the iguanodon's case) not even as a reptile — he thought it was a rhino-like mammal or even a fish! It was his English colleague Richard Owen that did that, announcing in 1845 the creation of the name Dinosauria in a scientific meeting in Plymouth. Even though Dino-saur is usually translated in "terrible lizard", Dino- can also be seen as "magnificent", "fearfully great", while the meaning of -saurus can be extended to "reptile" (non necessarily a lizard). Owen described dinosaurs as a subclass of the Reptilia recognizing them as the apex group of the reptile class, sharing some anatomical traits with mammals.note  After the invention of the group name, Owen himself described several new genera of english dinosaurs from the 1850s to the 1880s, usually herbivores (the carnivores were mostly classified in the genus Megalosaurus). The best-known today include the small biped Hypsilophodon (which was initially believed a tree-climber, not a ground-runner), the primitive armored Scelidosaurus, the first-found stegosaur (Dacentrurus), the spiky ankylosaur Polacanthus, and the first-found sauropods, the huge Cetiosaurus and Pelorosaurus. Cetiosaurus means "whale lizard": because of its 18 m long backbone (and because its limbs weren't initially found) it was believed by Owen another kind of marine-reptile, until Owen himself described the cetio's limbs about 30 years later.

About the still-visible-today sculptures of the Crystal Palace Park made in London in year 1856 by artist Benjamin Waterhouse Hawkings, see Stock Dinosaurs: "Iguanodon", Stock Dinosaurs: "Megalosaurus", and Prehistoric Life: "Hylaeosaurus". These sculptures reflected and popularized Owen's own vision of the extinct animals — in contrast with Mantell's and Cuvier's ones, not to mention Owen's contemporary Charles Darwin. It's noteworthy that the park popularized also several other extinct creatures other than the original three dinosaurs, usually in a quite inaccurate way just like the dinos: the original marine reptiles Ichthyosaurus, Plesiosaurus, Mosasaurus, the original flying reptile Pterodactylus, mammals of several kinds (ex. the "giant deer" Megaloceros but also critters that are relatively little-known today such as Anoplotherium), the jurassic crocodilian Teleosaurus, the first-found giant amphibian (Labyrinthodon) , and the first-found mammal-like "reptile", Dicynodon.

  • In continental Europe

The other european country that mainly contributed to the early dino-paleontology is Germany. Here, Hermann Von Meyer described the first bones of Plateosaurus in the 1830s (before Owen created the word "dinosaur", but the plateosaur wasn't included in the group initially), and in the 1863 announced to the scientific world what since then has often been celebrated as "the most important fossil ever discovered": Archaeopteryx. As just in those years Charles Darwin had announced to the world his theory of Evolution, the archaeopteryx ("ancient wing", or the Urvogel for friends) has since then been celebrated as every sort of "missing-link": between reptiles and birds, between cold-blooded and warm-blooded animals, and even between "lower animals" and "higher animals" (an outdated distinction sounding even a bit "racistic" to modern biology, see also "Other Extinct Creatures"). Even though in the same years Darwin's colleague Thomas Huxley more correctly put the archaeoptere as the missing link between dinosaurs and birds, this placement was proven true only in the second half of the 1900 century. Today Archaeopteryx is more and more losing its former prestige, and now it's considered just a simple feathered theropod among the others.

Also the original Compsognathus specimen was found in Germany in the same site and period of the archeopteryx (the other known specimen was found in southern France in full XX century); the compsognath was the first non-bird dinosaur found with a nearly complete and still-articulated skeleton, and proved that some small dinosaurs were bipedal (while the bigger ones were still considered quadrupedal by everybody at the time). Both Archaeopteryx and Compsognathus were found in the classical "death posture" with their neck turned backwards (we still don't know why so-many dinosaurs have been found in such a way). The "compy" example also demonstrates that really small dinosaurs were already known to science well before the great entry of dinosaurs in the XX century pop-culture: obviously, films and non-documentary media have usually ignored them — for example, Compsognathus waited 130 years until it was definitively popularized in the 1990s thanks to one single popular series (which portrayed it in an unrealistically overscary way to make it interesting to the public). Even the long-tailed pterosaur Rhamphorhynchus was found in XIX century Germany in the same site of Archaeopteryx and Compsognathus (Solnhofen, in Bavaria). The print of the rhamphorhynch's membrane-wings ultimately demonstrated that pterosaurs were flying creatures (though believed by most experts as very poor flyers until the second half of the XX century).

In the 1870s, one of the most unexpected discovers was made in the small country of Belgium, near the town of Bernissart: a "graveyard" of about 40 Iguanodons found... into a coal mine. The completeness of several specimens made the belgian scientist Louis Dollo able to re-describe this dinosaur in a more updated way, as a bipedal critter with a kangaroo-like posture and browsing the tree-tops like a giraffe (and even with a giraffe-like extensible tongue). Just few years later other spectacular "dino-graveyards" made of other kinds of dinosaurs will be found in the USA, and in the XX century still others will astonish researchers in USA, Canada, Europe etc.

  • In the USA

The first confermated dino-remains found in the USA (and in the Americas as a whole) were simple isolated teeth. They were found in the 1850s and described by the main expert of the time of the USA, Joseph Leidy: Trachodon, Troodon, Palaeoscincus, and Deinodon. Deinodon was probably a tyrannosaurid, Trachodon a hadrosaur, Palaeoscincus an ankylosaur, and Troodon a small carnivore. Only Trachodon and Deinodon were recognized as dinosaurs initially (more precisely as american relatives of Iguanodon and Megalosaurus respectively) while Palaeoscincus and Troodon were considered simple lizards (Palaeoscincus means "ancient skink"), and later reclassified as dinosaurs. In the following decades all them were treated as "wastebins", attributing to them other remains found later which is hard to say if they really pertain to them.

The first really important dino-find was made by fossil-collector Foulke in New Jersey few years later: the first proper dino-bones (mainly leg bones). They belonged to an animal related with Iguanodon & Trachodon called by Leidy Hadrosaurus foulkii ("Foulke's heavy lizard") in 1858. Leidy noted that the frontlimbs were much shorter and weaker than the hindlimbs, and explained this fact in the only way possible: it walked on just two legs. This implied automatically that even Iguanodon should have been bipedal as well, but most scientists of the time hardly accepted that 10 m long, multi-tons animals could be bipedal like birds or humans — and this would have made outdated the popular quadrupedal dino-sculptures of Crystal Palace created just 2 years before in England. Hadrosaurus was also the first dinosaur mounted in an exposition; it was even created a life-sized model of it in Central Park in New York (always by Benjamin W. Hawkings) together with several other extinct critters, in an exposition just like that of the Crystal Palace in London. Unfortunately, the models were destroyed by the local corrupted politics (the "boss" William Tweed) because they didn't make money enough: the fragments of the sculptures were buried in the Central Park, and are still to be found today.

Even though the start of american dino-science is usually put in the 1850s, to be more correct some important dino-findings had already been made in New England much before Leidy's discovers (we're talking about the start of the century), but weren't initially associated with dinosaurs. Several footprints of theropods of uncertain attribution, that were initially mistaken for prints of a giant bird (some went far away to think they were made by Noah's crow!); and the early dinosaur Anchisaurus, whose incomplete fossil was found in 1818 (even before the description of Megalosaurus), but was recognized as a dinosaur only at the end of the century. note 

LATE 1800: the "Bone Wars"

After the first American discoveries above, two palaeontologists of the North-East of the USA, Edward Drinker Cope & Othniel Charles Marsh, were attracted by the great plenty of fossil material casually found in the Far West by their collaborators (Arthur Lakes, Georges Lucas, John Hatcher and others). Initially friends, Cope's and Marsh's wish of glory and scientific prestige caused them becoming archrivals for their whole life. They obsessively searched for the most spectacular dinosaur possible and then published the discover in scientific papers, often slandering each other in the media —- and arriving to the point to destroy some fossils found by the other scientist! However, we have to thank them if so many dinosaurs were found in this period: among them, just the most famous dinosaurs in the XX century. (Popular interest in dinosaurs was still bland at Marsh's & Cope's times). Many names of dino-groupings were also created within the "wars": Theropods, Sauropods, Ornithopods, Stegosaurians, Ceratopsians, Hadrosaurians — some of these groups were invented just to include bone-wars dinosaurs. The abundance and completeness of the remains had no equals elsewhere (not counting the Bernissart Iguanodons which were found nearly the same years): the controversial hypothesis about giant bipedal dinosaurs was ultimately proven true thanks to these findings, which showed not only iguanodons and hadrosaurs but even giant carnivores walked on two legs. note 

One of the first animals described by Marsh was the today-obscure sauropod Atlantosaurus immanis (immanis = immense), publicized as "the biggest creature that ever lived" (extimated even 40 m/130 ft long, twice a Real Life apatosaurus and even longer than a Real Life diplodocus!). Cope responded with his Camarasaurus supremus (supremus = the biggest), also initially extimated up to 40 m/130 ft of length. But it was Marsh that won the sauropod-competition describing the two most famous sauropods, Apatosaurus and Diplodocus indeed (but also Barosaurus). It was also Marsh the responsible of both the notorious "Brontosaurus" misunderstanding, and the classic theory about water-living sauropods lasted until the late 1900. It's worth noting that both scientists often discovered the same animals, but gave them different names; usually the names coined by Marsh are still valid today while the Cope's ones are simple invalid synonyms (just see Cope's "Laelaps" and Marsh's Dryptosaurus); exceptions are Camarasaurus, Coelophysis & Monoclonius, all Cope's creations. But the Marsh ones include names like Stegosaurus, Triceratops, Allosaurus other than Apatosaurus, Brontosaurus, Diplodocus. Also named by Marsh were: the horned carnivore Ceratosaurus, the ornithopods Camptosaurus and Dryosaurus, the small carnivore Coelurus, the ceratopsid Torosaurus, the ankylosaur Nodosaurus, and Ornithomimus, the first-known "bird-like dinosaur" (meaning just "bird-mimic"), but believed only incidentally similar to birds and not related with them. Curiously, Cope described some "sensational" animals that are not much known today: the huge allosaur Epanterias and the mysterious giant vertebra of Amphicoelias (which has recently become popular thanks to Internet). And it was Cope that discovered the first complete hadrosaur skeletons, named Trachodon copei (now called Anatosaurus copei, Edmontosaurus copei or Anatotitan copei, see Stock Dinosaurs)

It's also worth of note the fact that some non-dinosaurs that are stock today were also found during the "bone-wars" (usually by Marsh): the pterosaur Pteranodon, the plesiosaur Elasmosaurus, the mosasaur Tylosaurus, and the mammal-like Dimetrodon. Not to mention some extinct big mammals, like Uintatherium & Brontotherium, and the couple of proto-birds Hesperornis & Ichthyornis. More precisely, however, Elasmosaurus was discovered and described by Cope slightly before the beginning of the scientific competition: there is a curious story tied with the elasmo's reconstruction made by Cope (see "Heads or Tails?")

EARLY 1900: dinosaurs everywhere

In this time the dino-groups that are the most familiar today (giant quadrupedal sauropods ceratopsians & stegosaurs and erect giant carnivores) made their triumphant entry in the western pop-culture. The old four-legged dragons of the british "crystal palace park" were replaced by much more diversified animals with long necks, horned heads, armored backs, upright stances, bird-like bills and so on. For the joy of pop-culture-makers this available diversity increased even more just in this period: in Europe, Asia, Africa, and expecially North-America were (sometimes re-) discovered many new kinds of dinosaurs that soon later joined their relatives in museums, paleo-art, and sometimes films and cartoons. Above all, they added more material for scientists to rebuild the mosaic of the dino-evolution. Among them, english Harry G. Seeley note  was able to separate dinosaurs in two great branches: Saurischians & Ornithischians.

  • In the USA

If we don't count two of the greatest (in all senses) dino-stars, Tyrannosaurus rex and Brachiosaurus (both announced just at the start of the century) note  the fossil sites of Eagle Land has not added many new genera to the world-dinosaur-list in the first portion of the XX century. Rather, several skeletons of already-known creatures were dug out in the same places where the "bone-wars" were "fought" some decades before: ex. the famous two Diplodocus skeletons found thanks to Carnegie's money and enthusiasm, the "bone-quarry" in Utah full of Allosaurus dead in a prehistoric tar-pit, and even a small "hut" made of sauropod bones discovered by Earl Douglass where today is the Dinosaur National Monument (between Utah and Colorado, and a great source of Jurassic dino-bones still-today). More spectacular was the discover of the so-called "Trachodon mummies" which showed the first ever remains of skin and even muscles in a dinosaur fossil; but from the 1930s until recently the "bone-wars" Trachodons and the "mummies" were rechristened Anatosaurus. Among brand new animals described in early 1900, Ornitholestes (which joined Coelurus and Compsognathus among the typical small Jurassic theropods), the ceratopsid Pentaceratops found in Texas, and the "last-surviving american sauropod" Alamosaurus. Among non-dinosaurian reptiles, the giant turtle Archelon was found in South Dakota slightly before the start of the 1900.

  • In Canada

After the discover of the first skull of the T-rex relative Albertosaurus made by Joseph Tyrrell in Alberta at the end of the XIX century, much more new type of dinosaurs came to light in this canadian province. The latter revealed itself to be a veritable "mine" of Late-Cretaceous dinosaurs, increasing drammatically the relatively-low number of animals known from the end of the Dinosaur Era (most bone-war dinosaurs were Jurassic). Within this context, several characters competed with each other for "the one that excavates the best fossils" title, similarly to what Cope & Marsh did previously in the western USA (but, fortunately, not with such a hatred among them): because of this, some have named this competition the "2nd great dino-rush". The main fossil-hunters were Barnum Brown (the same guy who had found the first two T.rex skeletons some years before), the Sternberg family, and Lawrence Lambe; the main field was the badlands around the Red Deer River not far away from Alberta's capital Edmonton.

The discoveries included all the main Late Cretaceous dino-groups, but expecially ceratopsians and hadrosaurians. Among the former, the hook-frilled Centrosaurus (maybe a synonym of Cope's Monoclonius), the triangle-shielded Chasmosaurus and Anchiceratops, and the spectacular multi-spiked Styracosaurus (which managed to enter the pop-culture thanks to its look), but also the no-horned Pachyrhinosaurus and the small semi-bipedal Leptoceratops — and, of course, several new specimens of Triceratops (expecially skulls, so varied in shape that some arrived to recognize more than 15 distinct Triceratops species!). Among hadrosaurians, the huge Edmontosaurus regalis (whose name is a clear reference to Edmonton), the glove-crested Lambeosaurus lambei (named after L. Lambe), the allegedly hump-nosed Kritosaurus and the really hump-nosed Gryposaurus, the dish-crested Corythosaurus & Hypacrosaurus and, more famous of all, the tube-crested Parasaurolophus — the name of the latter was in turn ispired from another hadrosaur found in these sites, Saurolophus. And then, the armored ankylosaurians (which were definitively recognized distinct from stegosaurians): Euoplocephalus ("well-armored head"), Scolosaurus (long believed a synonym of Euoplocephalus), Panoplosaurus ("wholy-armored lizard"), Edmontonia (Edmonton again), and the prototype of the group, Ankylosaurus ("fused lizard"), but also some remains included in the "wastebin taxon" "Palaeoscincus".

All these new findings enhanced the dino-classification as a whole: for example, ceratopsids were separated between long-frilled and short-frilled (the former including Torosaurus, Pentaceratops, Chasmosaurus, Anchiceratops, Arrhinoceratops, the latter Centrosaurus, Monoclonius, Styracosaurus, while Triceratops was often considered intermediate between the two subgroups. While before 1900 only non-crested kinds were known, the new hadrosaurs included both crested and crestless dinosaurs (Saurolophus just means crested lizard, and also Prosaurolophus and Brachylophosaurus have references to crest in their names) and some ankylosaurs like Ankylosaurus and Euoplocephalus revealed a club on their tailtip (unlike the bone-wars Nodosaurus which was clubless).note  It was even recognized distinct from Albertosaurus another "small" T. rex relative, Gorgosaurus ("monstrous lizard"). Interestingly, the albertosaur and gorgosaur fossils were more complete than those of the super-famous T.rex, often with the typical tiny two-findered forelimbs preserved — those of the rex were found for the first time in the 1980s and 1990s! The Alberta's fossil sites also revealed smaller slender animals: among them, the first complete ornithomimids (the name Struthiomimus ["ostrich mimic"] was coined in this time), the first incomplete "raptor", Dromaeosaurus( "running lizard") and its relative Stenonychosaurus ("thin-nailed lizard", today synonimized with Troodon), the unclassifiable small theropod Chirostenotes ("slender hands", nowadays known to be an oviraptorosaur), the hypsilophodontians Thescelosaurus ("beautiful lizard") and Parksosaurus ("Parks's lizard": William Parks was another fossil-hunter of the "2nd dino-rush"), and the first-found pachycephalosaurian, Stegoceras ("horned roof"), whose bulged thickened head has long been a mystery, to the point to have even been considered a deformity due to illness.

  • In Europe

The main figure of dino-expert there was Friedrich Von Huene who divided theropod dinosaurs into Carnosaurs and Coelurosaurs and discovered a huge graveyard of Plateosaurus in his country (Germany), making the latter one of the best-known triassic dinosaurs since then, and the typical example of the new subgroup conceived by Huene, the "prosauropods" ("before the sauropods"), initially believed carnivorous and then herbivorous or omnivorous. Also found in Europe at the start of the 1900 were two tiny early theropods, Procompsognathus ("before Compsognathus") from Germany & Saltopus ("hopping foot") from Scotland, the much bigger sauropod Hypselosaurus from France (maybe the owner of the biggest ever-found non-bird dinosaur eggs), the sail-backed theropod "Altispinax" (former "Megalosaurus" species, renamed Becklespinax in the 1990's), and some Late Cretaceous "dwarf dinosaurs" found mainly in Romania such as Struthiosaurus, Rhabdodon, Telmatosaurus, Magyarosaurus (most of them described by another European scientist of the time, Franz Von Nopsca). Also Ornithosuchus and Saltoposuchus, both bipedal crocodilomorphs considered at the time as dinosaur-ancestors or (in the case of Ornithosuchus) even early theropods, were found in Great Britain in this period.

  • In Africa

Two animals dominated the early XX century of paleontological Africa: Spinosaurus and Brachiosaurus. The former was found in Cretaceous Sahara, but because of its fragmentary remains it was initially described as a carnivore smaller than T. rex and with nothing interesting apart from the crest of its back (which was thought substaining a "sail" like that of the non-dino Dimetrodon); the reconstruction as a predator bigger than T. rex (and possibly with a hump on its back) and with croc-like jaws came ultimately to light only in the 2000s. Also Carcharodontosaurus was found in Cretaceous Sahara in the early XX century (together with the sauropod Rebbachisaurus); the carcharo was described from even more incomplete fossils than the spinosaur's (merely some pieces of bone and some teeth) as a generic carnivore only 7 m long, half the length of a Tyrannosaurus. The african brachiosaur was discovered far souther, in Tanzania, and being the first complete specimen of brachiosaur ever found became the model of all the classical brachiosaurs found in popular culture. Both dinosaurs were found by German scientists (E. Stromer & W. Janensch respectively) note  and stored in German museums; sadly, World War II aerial bombing destroyed most of the Spinosaurus ones, while the "Brachiosaurus" (renamed Giraffatitan since 2009) is still towering in the Berlin Nature Museum.

Other dinosaurs came to light in that years in the same site of the brachiosaur (Tendaguru), all from Late Jurassic: the small spiky stegosaurian Kentrosaurus (whose couple of lateral spikes were until-recently put on its hips instead of on its shoulders), the mysterious small carnivore Elaphrosaurus (believed at one moment the ancestor of ornithomimids), some sauropods (expecially the short-necked Dicraeosaurus and another longer-necked diplodocoid traditionally classified in the north-american genus Barosaurus), and some dinosaurs already known from Jurassic North America (the small bipedal herbivore Dryosaurus, and maybe even the big carnivores Allosaurus and Ceratosaurus). As a whole, the Tendaguru animals are very similar to those found in the USA during the Bone-Wars, and this was mentioned as a concrete proof about the Pangea theory and the Drift of Continents.

South Africa was the source of some early dinosaurs, such as the first fragmentary remains of the prosauropods Massospondylus and Euskelosaurus (among the few dino-remains found in Africa before the XX century) and the sauropod-ancestor Melanorosaurus. But the main discoveries here regarded non-dinosaurs: Robert Broom and other scientists found several of them living in the Early Triassic (before the apparition of the first dinosaurs): many new "mammal-like reptiles", among them the very-close-to-mammals Cynognathus & Thrinaxodon, and also what was long believed one ancestor of dinosaurs, the archosauromorph Euparkeria.

  • In Asia

The first Asian fragmentary dino-remains were found in India: the late-surviving sauropod Titanosaurus, which was treated as a "wastebasket taxon" since that attributing to it incomplete sauropod remains found in Europe and South America. note  In China the first discovery was a very incomplete hadrosaur (Mandschurosaurus) in the 1920s and later the sauropod Euhelopus in the 1930, both found by western non-chinese scientists.

Apart from these exceptions the first really-important asian dinosaurs were discovered in Mongolia by american naturalist and adventurer Roy Chapman Andrews, which was working for the American Nature Museum in New York (at the time led by Henry F. Osborn, the guy who named Tyrannosaurus rex as well as other dinosaurs found in early 1900). Andrews and his team made in the 1920s a perilous expedition in Mongolia, precisely in the Gobi Desert. They were largely rewarded: Andrews found the first remains of what he believed the common ancestor of the horned dinosaurs, Protoceratops ("first horned face"). But even more importantly, they were coupled with some eggs Andrews attributed to the protoceratops, which seemed demonstrating once for all that dinosaurs layed eggs exactly like modern reptiles do note . Near those eggs was also found a crushed Oviraptor skull. Osborn named it so because gave the possibility it was a specialist egg-robber, see Stock Dinosaurs. The expedition also discovered the very first incomplete Velociraptor remains —- not even furtherly imagining the huge success this name will gain 80 years later. And then, the first specimens of the "parrot-bill" Psittacosaurus (recognized as an ancestor-of-ceratopsids only since the 1970s-80s, and recently become one of the best-known members of the dinosaur world, with several species, adults, babies and nests described), the club-tailed Pinacosaurus (still-today the most abundant Asian ankylosaur), and the Velociraptor-relative Saurornithoides.


The middle portion of the XX century is sometimes known as "the dinosaur Middle Ages": from the 1930s-1940s to the 1960s-1970s few new dinosaur kinds were added to the list, and very few new theories about their life were ideated. The classic image of "big stupid beasts condemned to extinction" was dominant, filling many movies and popular reconstructions of the time. If dinosaurs went extinct, it was said, was because they were badly-adapted to their environment, and their typical features (crests, horns, plates, and so on) were considered absurd "monstruosnesses" without any evolutionary signifiance. In short, they were Too Dumb to Live and were simply outcompeted by the best and most noble lineages of vertebrates, mammals and birds (the latter were believed descending directly from triassic non-dino reptiles and not dinosaurs at all).

North America assisted the last findings of the former dino-rush. From Wyoming came Pachycephalosaurus aka the modern prototype of the thick-headed dinosaurs in the 1940s, recognized as ceratopsian-relatives only in the 1980s and classically described as headbutters. Then, in the fifties it was found the huge allosauroid Acrocanthosaurus (which was put in the spinosaurid family only because it has a small sail on its back). In the sixties, Edwin Colbert (who is noted also for have written the first popular informative dinosaur-books) discovered the huge graveyard of Coelophysis in Ghost Ranch (New Mexico), making the coelophysis joining Plateosaurus as the most best-known early dinosaur, and leading the hypothesis that Coelophysis was cannibalistic (since some alleged young coelos were found inside the ribcages of some adults). In Europe, "Megalosaurus" was still treated as a Wastebasket; however, the english theropod Eustreptospondylus was deemed distinct from Megalosaurus in the 1930s. Also from this period is the description of the stegosaur Lexovisaurus, which joined Dacentrurus as one of the few european stegosaurians.

Just as interesting were the dino-news from the asian Far East: the second great dino-hunt in Mongolia (after that of Andrews, this time led by Russian scientists such as Ivan Efremov) revealed in the 1950s the eastern T.rex relative Tarbosaurus bataar (initially classified as Tyrannosaurus bataar and found with its forelimbs preserved like Albertosaurus and unlike Tyrannosaurus rex), the asian species of the hadrosaur Saurolophus (which demonstrated that North America and Asia were united at Cretaceous times by a landbridge), the clubbed ankylosaur Talarurus, and the huge claw of Therizinosaurus (initially not recognized as a dinosaur but a marine turtle!). It were also found than several new specimens of Protoceratops (nicknamed the "sheep of the Cretaceous" just for its abundance) with its first true nests and eggs, and some new remains of Oviraptor and Velociraptor. Meanwhile, in China, Young Chung Chien (the father of Chinese paleontology) announced the first well-preserved dinosaurs found in his country: the huge-necked sauropods Mamenchisaurus and Omeisaurus, the unicorn-like hadrosaur Tsintaosaurus, other than the first asian stegosaurs and carnosaurs (Chialingosaurus and Szechuanosaurus respectively), and the early prosauropods Lufengosaurus and Yunnanosaurus — the former starting the tradition of portraying dinosaurs in postage-stamps. There were also some chinese dinosaurs still described by western scientists, namely the tiny bipedal ceratopsian Microceratops.

THE 1970s AND 1980s: the Great Renaissance

The dino-discover that dominated the 1970s was undoubtly Deinonychus, the "sickle-clawed dinosaur", found in Early Cretaceous Montana by John Ostrom slightly before the decade. He described it as a cunning vicious hunter of big game (namely the long-tailed ornithopod Tenontosaurus, also found by Ostrom), so debunking the traditional vision of all dinosaurs as slow and foolish, and leading to the famous "Dinosaur Renaissance" led mainly by Ostrom's pupil Bob Bakker. Ostrom also noted the skeletal similarites between Deinonychus and Archaeopteryx, an hypothized that birds were direct descendants of dinosaurs and not just relatives. As a logical consequence many scientists started to think even some non-bird dinosaurs were feathered, but as there were no proof about this illustrations from these two decades usually showed dinosaurs entirely scaled.

Meanwhile, in Mongolia, the third historical expedition there (this time led by Polish scientists, among them Osmolska) note  uncovered the famous combat between Velociraptor & Protoceratops. The new Velociraptor remains showed it was similar to both the recently-found Deinonychus and the more classical Dromaeosaurus; so a Canadian palaeontologist, Dale Russell, decided to put Deinonychus, Dromaeosaurus & Velociraptor in the same family, Dromaeosaurids. note  Also another Jurassic Park guy, Gallimimus, was found in Mongolia in the Seventies during this polish expediction, as well as the galli's relatives Archaeornithomimus, Anserimimus, Garudimimus, Harpymimus, and the huge Deinocheirus (better, the latter's forelimbs). A variety of other animals was found in this expedition: among them, the flat-headed pachycephalosaur Homalocephale, the extremely well-preserved skull of the latter's relative Prenocephale, the large ankylosaurians Saichania and Tarchia, the near-hadrosaur Probactrosaurus (which proved the duckbills' ancestry from iguanodonts), the headache-troubling remains of the Mix-and-Match Critter Segnosaurus, the Tongue Twister -sounding Opisthocoelicaudia which was the first complete (head and neck apart) skeleton among Late Cretaceous sauropods, and a brand new variety of Oviraptors with a strange crest on their head (recently recognized not belonging to the genus Oviraptor). Souther, in the Popular Republic of China, Dong Zhiming started adding new dinosaurs to his predecessor Young's list: among them the stegosaur Tuojiangosaurus, Wuerhosaurus, and Huayangosaurus, the carnosaur Yangchuanosaurus, the club-tailed sauropod Shunosaurus, the huge-named Micropachycephalosaurus, and the much shorter-named theropod Gasosaurus. In the 1980s, a Canadian-Chinese expedition found a whole herd of juvenile Pinacosaurus in the border between proper China and Mongolia. Also in China, in the northern province of Shantung, was found one of the biggest hadrosaurs ever, Shantungosaurus, while its much smaller relative Bactrosaurus is still today one of the few dinosaurs known from the ex-USSR. At the other end of Asia, in India (which was not part of Asia at the dinosaurs time but a huge island), a very fragmentary plesiosaur, Dravidosaurus, was wrongly publicized as "the last-surviving stegosaur", while another dinosaur, Barapasaurus, was correctly described as one of the first-appeared sauropods.

In Southern Africa, the curious tusked Heterodontosaurus and the more generic Fabrosaurus and Lesothosaurus (the latest two are perhaps the same animal) gave new light to the ornithischians' first evolutionary steps, as well as new more complete remains of Massospondylus and a newly-found extremely early sauropod (Vulcanodon) did with the sauropodomorph branch. Vulcanodon was more precisely found in Rhodesia (today Zimbabwe), together with the small coelophysis-relative Syntarsus. In Northern Africa a sail-backed animal, the "duck-billed iguanodont" Ouranosaurus, joined the other more famous sailback, Spinosaurus.In Argentina Jose Bonaparte discovered for the first time an armored sauropod, Saltasaurus (which is today the most best-known Cretaceous longneck) and the theropods Abelisaurus and Carnotaurus (the latter astonished experts for its bullhorn-like head, tiny forelimbs, and for having revealed the best print of skin ever in a large dinosaur), as well as several other dinosaurs: the small dromeosaurid-like Noasaurus from Cretaceous, the small hadrosaurs Secernosaurus and "Kritosaurus australis" also from Cretaceous, the sauropod & carnosaur Patagosaurus and Piatnitzkysaurus from Jurassic, the "prosauropods" Riojasaurus and Mussaurus from Triassic, and so on. But the most primitive of them all, Staurikosaurus & Herrerasaurus, were not described by Bonaparte — Staurikosaurus was not even found in Argentina but in Brazil. The description of these two middle triassic small carnivores broke up for some time the dichotomy Saurischians vs Ornithischians, as they were believed too primitive to belong to either; today they are believed very unspecialized saurischians. Also from Middle Triassic was Pisanosaurus, discovered in the same years in Argentina and still-today the earliest known ornithischian.

In the USA, other than Deinonychus was announced the early jurassic double-crested Dilophosaurus (formerly believed a species of the "wastebasket taxon" Megalosaurus), described either as the "first powerful meat-eating dinosaur" or a modest carrion-eater. Its possible prey, the small armored Scutellosaurus was also found in the 1970/80's, as well as the much larger cretaceous ankylosaurs Sauropelta and Silvisaurus, the spiky pachycephalosaur Stygimoloch, the tiny oviraptorosaur Microvenator, the small hypsilophodontian Othnielia rex (maybe the same animal of Nanosaurus, found during the Bone Wars in the same location), the small ceratopsid Avaceratops, the large jurassic carnivore Torvosaurus, and the small tyrannosaur Nanotyrannus (maybe a simple youngster of T. rex) among the others. Meanwhile (also in USA) James Jensen resurrected the old tradition of ballyhooing incredibly huge sauropods to the media: his Supersaurus was briefly "the biggest dinosaur ever" until the even bigger "Ultrasaurus" was announced by Jensen some years later. In Canada, Phil Currie found a huge herd of Centrosaurus dead together in a flood, giving one of the first proof about migrating dinosaurs. He also described Troodon as "the biggest-brained dinosaur" and a particularly smart animal — to the point his colleague Dale Russell got this Up to Eleven thinking it could have become similar to a humanoid if survived to the extinction. Dale Russell also lumped Gorgosaurus into Albertosaurus (but judged Daspletosaurus distinct from the latter) and separated "Dromiceiomimus" from Ornithomimus. But the most prominent north-american palaeontologist of the time was perhaps Jack Horner. In the 1980s, his discover in Montana of the nests of the hadrosaur Maiasaura (and then, those he attributed to the smaller ornithopod Orodromeus) got ultimately the proof that some dinosaurs underwent parental care just like mammals and birds, representing the apex of the "dino-renaissance". In England great mediatic coverage was dedicated to Baryonyx, a new kind of big theropod totally different to the others, specialized to fishing. Also in the U.K. David Norman re-described Iguanodon from bipedal to semi-quadrupedal. While in the other side of the world, the first complete Australian dinosaurs came to light: the most known is perhaps the bulge-nosed iguanodontian Muttaburrasaurus, and then the small hard-to-classify ankylosaur Minmi, the tiny large-eyed biped Leaellynasaura, and the alleged "australian Allosaurus". Finally, the Ice Continent unvealed its first dinosaurs: an (for 20 years) unnamed ankylosaurian - Antarctopelta - and a (still-today) unnamed hypsilophodontian, both found in the ice-free portion of Antarctica.

  • Great Failures of the Evolution?

Other than the main discovers of parental care, several other new theories about dino-life and biology were proposed in the seventies-eighties, which made dinosaurs more similar to mammals and birds than previously thought (expecially enthusiastic about this was Bob Bakker). Land-living sauropods able to lift on their hindlegs to reach high vegetation and to use their tails as whips against enemies, ceratopsids locking their horns in combats, hadrosaurs making noises to communicate to each other (the famous crest of Parasaurolophus was described as a sort of "trumpet"), stegosaurs using their plates as a thermoregulation device (not defense as traditionally said), pachycephalosaurs headbutting each others for mating purposes, mass-migrations of herbivores like those of wildebeest, the possible ability to change the colors of some portions of the body, and of course the (today disputed) hunt in packs of the dromaeosaurids and perhaps even allosaurs. All this not mentioning the long-standing dispute about the dinosaurs' warmbloodness, which is a particularly complex argument we don't deepen here about. The dinosaur's limbs became ultimately erect and pillar-like like those of elephants and birds, the bipeds' body became horizontal, the tail became more rigid and not dragged, the ornithischians' head achieved cheeks to allow the grinding-up of vegetation, and even the first feathered portrayals of theropods appeared occasionally.

And then the new theories about the final extinction of the dinosaurs. The first signals of a deep impact came from the early 1980s, when the Nobel-Prized Luis Alvarez discovered much iridium in the rocks of 65 million years ago. Since iridium is common in meteorites but rare on Earth, he thought this element came from space. The final proof of the impact came to light in 1993-94 (just in the same years of the first movie Jurassic Park), when the remains of the Chixculub Crater were discovered in southern Mexico ashore the Yucatan Peninsula. Also the discover of volcanic activity at the end of the Cretaceous came about in the same years (the "fossilized" lava in Southern India). Many of these theories made their way in popular culture since the 1980s: an excellent example is the animated movie The Land Before Time, which shows migrating dinosaurs, parental care, terrestrial sauropods, and an extremely agile & active tyrannosaur — even though the film is still partially tied with outdated theories, ex. bipedal dinosaurs with erect bodies, water-loving hadrosaurs, splayed-legged ankylosaurs, and the mass-extinction due to changes in the Earth-Surface and not asteroids or comets.

THE 1990s

In the Jurassic Park decade the main discover was certainly the first print of feathers found in non-avian dinosaurs, in 1996. Before that, only Avimimus (found in 1980 in Mongolia) seemed showing some proof of feathers, but not prints. Then, Sinosauropteryx, Caudipteryx, and other animals found in northern China changed our perception of dinosaurs, which were much more bird-like than usually thought. Today, dozens of feathered dinosaurs are known, as well as some animals which have had some relation with the bird-dinosaur argument — the alleged "first bird" Protoavis, and Mononykus (which was initially believed a true bird). Also determinant in the scientific perception of dinosaurs was the coming of the revolutionary Cladistic method of classification which partially substituted the traditional Linnean one. Cladistic has revealed expecially useful for the theropod classification, for example changing the traditional division carnosaurs-coelurosaurs into a much more complex one.

In North America, the diplodocid "Seismosaurus" competed with "Ultrasaurus" in the early 1990s for the "biggest land animal ever" title; today, both animals are considered invalid by official science. Meanwhile, the first really-complete Tyrannosaurus rex skeletons (even with forelimbs and the end of the tail) were found in USA, notably "Sue" note . The traditional "Anatosaurus" was divided into Edmontosaurus & "Anatotitan" in 1990; the discover of Utahraptor upscaled dromaeosaurid size at 7 m of length since 1993. It was also confirmed even Alaska was populated by dinosaurs: the ceratopsid Pachyrhinosaurus has revealed in the 1990s a huge fossil herd near the Polar Circle.

Among other continents, South America was particularly plenty of interesting animals: the tiny Eoraptor (long believed the first-ever dinosaur) in 1993, the sail-backed sauropod Amargasaurus in 1990, the nesting ground of Saltasaurus in 1998, and the incomplete remains of Argentinosaurus (which in turn took over to "Seismosaurus" and "Ultrasaurus" the "biggest ever!" title, now contented by other guys, expecially "Amphicoelias"), and later those of Giganotosaurus that, together with Carcharodontosaurus, was presented as "bigger than T. rex"; today the record-holder among theropods is officially Spinosaurus (which was re-described in the 1990s as more similar to the fishing Baryonyx above than to Tyrannosaurus or Allosaurus). In Mongolia, Oviraptor (better, Citipati) revealed not to be an egg-stealer as traditionally thought. In Italy, the tiny Scipionyx showed the very-first internal organs in a dino-fossil —- while the alleged "heart" of Thescelosaurus found a bit later in the USA is probably a simple piece of stone casually heart-like.

THE 2000s

The New Millennium opened with an unespected find in Northern China: a four-winged dromaeosaurid, named Microraptor, which demostrated once for all that birds are dinosaurs. Later, also in China, some paleontologists started the trend to name chinese dinosaurs with the suffix -long (ex. Guanlong). Meanwhile, the BBC producers popularized some new theories about dino-life thanks to their computer-graphic: rigid-necked sauropods, for example. Other theories emerged from CGI studies include: non-headbutting pachycephalosaurians, non-killing-in-pack dromaeosaurids, and non-quadrupedal prosauropods. Today, the biggest interest about dinosaurs regards their skin: it seems not only theropods but also herbivorous dinosaurs had some sort of feathers or feather-like structures: the quills on Psittacosaurus, the bristles of Triceratops, even the fleshy spikes of Diplodocus could have had the same origins of theropods' feathers, as (maybe) definitively demostrated by the discover of Tianyulong in 2009. Not forgetting that one close dinosaur relative, the pterosaur Sordes, had revealed signs of hair-like things already in the 1970s.

Talking about pterosaurs, they too have undergone a "renaissance" since the Seventies: the huge Quetzalcoatlus and several other kinds (Dsungaripterus, Pterodaustro, the early triassic Eudimorphodon, and many others) increased greatly the known ptero-variety, demonstrating "flying reptiles" being as diversified as modern birds in ecology, and as efficient as fliers. Since Eudimorphodon lived in the same epoch of the first dinosaurs and Quetzalcoatlus at the extreme end of the mesozoic note , it was clear at this point that pterosaurs inhabitated the earth across the whole dinosaur-era, 210-65 mya. While the 1 ft long Lagosuchus (found in the 1970s in Argentina) has demonstrated the evolutionary link between pteros and dinos. About other Mesozoic reptiles found since the 1970s are worth of note the marine plesiosaur Kronosaurus found in Australia, the huge ichthyosaur Shonisaurus found in North America, and the giant crocs Sarcosuchus & Deinosuchus, maybe able to transform large dinosaurs in their meals.

THE 2010s

As a whole, discoveries of the last years are seemingly conferming the scientific intuitions made in the previous decade. New feathered theropods and non-theropods are described each year, even some "classical" dinosaurs like Velociraptor and Ornithomimus have revealed some print of feathers. Dozens of new dinosaurian genera are described each year, with a rate much greater than has ever been (to give the idea, before the 1980s it was rare that more than two or three new dinosaurs added to the list each year), but note that many recent genera are described from few pieces of bone. Theories about dinosaur lifestyle flourish and contradict each other, and the dinosaur's evolutionary tree is relentlessly modified by new discoveries and studies, all this under the rules of the Cladistic method of classification which has definitively substituted the (inadequate for palaeontology) Linnean one. Not many, at least for now, the really-relevant discoveries: however, there have been some surprises here and there. The sudden increase of number of the known kinds of ceratopsids in year 2010, the find of the feathered theropods Sciurumimus and Yutyrannus in 2012 which showed feathers being "older" and more widespread than what was supposed, the first complete skeletons of the classic enigma Deinocheirus in 2014, and, last in order of time, the resurrection of the name Brontosaurus in the scientific dinosaur list in 2015.

And then, the non-stock dinosaurs divided in subgroups according to their real affinites and sometimes to their external appearence.