One of the tiniest dinosaurs known.
Sauropods include about three hundred kinds described so far. Other than the famous Power Trio Apato/Brachio/Diplodocus and the several contenders for "the biggest dinosaur" title, the most common sauropods in documentary-media have been Camarasaurus (mid-sized, short-necked, quite like a middle between an apatosaur and a brachiosaur), Cetiosaurus (a primitive generic-looking sauropod of Europe, the first described by science), Barosaurus (similar to Diplodocus but with a longer neck), Mamenchisaurus (found in Asia and with an even longer neck than the former), Saltasaurus (South-American, Cretaceous, and with an unusually armored body). Shunosaurus and Amargasaurus are noted as well for their body-defenses (club-tail and neck-spines, respectively). Other notable sauropods in non-fiction media have been: Titanosaurus (the prototype of the Titanosaurians), Dicraeosaurus (similar to Diplodocus but with a rather short neck), Vulcanodon (very small and basal, one of the first ever appeared sauropods), Hypselosaurus (the alleged owner of "the biggest non-bird dino eggs" ever found), and in the oldest sources, the fragmentary Atlantosaurus (the first sauropod described in the "Bone Wars"). The animal of the image is Diplodocus.
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Titanosaurs
The Last Sauropods
- “Titanosaur” is an often-heard name in documentaries, books and sometimes in pop-media: what is it exactly a titanosaur? Well, it has actually two meanings. The stricter one indicates a precise genus of Late Cretaceous dinosaur, Titanosaurus, the first sauropod discovered in India (and Asia), in year 1877. But it’s actually one of the most fragmentary sauropods, known only from few vertebrae and some other material, and was treated as one of the three most classic dinosaurian “wastebins” together with Megalosaurus and Iguanodon: to the point that Titanosauruses cropped up everywhere in the world - now they are regarded either dubious, or reclassified in new genera. The second meaning indicates the sauropod subgroup including the eponymous genus above: Titanosaurs. First appeared in the Late Jurassic with Australodocus
— initially believed a diplodocid, hence its name "southern (diplo)docus" — they became a very abundant and widespread dinosaur group in the Cretaceous, especially in the Southern Continents (where competition from the more evolved Ornithischians was lower), and in the Late Cretaceous they managed to replace all the other sauropods. Here we list only some noticeable titanosaurian examples.
Titans and Dwarfs: Antarctosaurus & Magyarosaurus
- Not all titanosaurs were true titans: among colossi such as Argentinosaurus, Puertasaurus, Futalognkosaurus, Paralititan, Patagotitan, Notocolossus, Dreadnoughtus, or Antarctosaurus, there was also an animal like Magyarosaurus, a dwarf sauropod only 6 m long, which reduced its size to survive in small European islands. Once often put in the "Titanosaurus wastebin", even though its name means "lizard of Hungary" it was found in the near Romania. About Antarctosaurus, this has been one of the first dinosaurs found in South America (since the start of the XX century: hence its generic name “Southern Lizard”), but is very poorly-known. Some alleged antarctosaur remains have been described in Africa and even India other than South America (the Indian one is now called Jainosaurus); some of these are nearly as big as those of Argentinosaurus found several decades later, as well as the equally-fragmentary remains of another early-discovered South-American kind, Argyrosaurus. Interestingly, the latter's name has the same meaning of Argentinosaurus, "lizard from Argentina", but the two titanosaurs are distinct animals. Both prefixes mean "silver" (Argentina means "the silver land"), but Argentino- is Latin word, Argyro- is Greek. Most titanosaurs, however, were far from the two extremes. The armoured Saltasaurus and the almost unutterable Opisthocoelicaudia, for example, were 12 m long— still half the size of an average apatosaur.
The Headless (in fossils): Opisthocoelicaudia
- "Titanosaurus", Antarctosaurus, Argentinosaurus, Argyrosaurus and so on are not the only fragmentary titanosaurian kinds: ironically, despite the high number of described species, titanosaur remains are almost always very scant. Just as an example, Opisthocoelicaudia from Late Cretaceous Mongolia is considered one of the most complete together with Saltasaurus; its body, limbs and tail are well-preserved … but its head and neck are unknown. The skeleton of Opisthocoelicaudia do not shows any sign of preserved body armor, and its tail is strangely curved upwards. It was originally classified as a Camarasaurus relative, as well as the less-known Asiatosaurus from Eastern Asia (maybe the first sauropod found in China, hence its generic name). But other titanosaurians, as said above, do show armor; these ones were the most evolved, from Late Cretaceous, usually small-sized for sauropod standards. To compensate, the most primitive ones were often enormous-sized to defend themselves against predators like the carcharodontosaurids. Among small armored Late Cretaceous titanosaurian, other than Saltasaurus we can mention Laplatasaurus "La Plata lizard". Its name is reference to the famous Argentinian river near which it was found: "Rio de la Plata" means river of the silver in Spanish. Like Antarctosaurus, it too has to some degree been treated as a "wastebasket" (some alleged "Laplatasaurus" were once described in Africa).
Mysterious Eggs: Hypselosaurus
- Most titanosaurian remains are from South America, especially Argentina. Most South American dinosaurs have been discovered in Argentina, and not in Brazil as one might expect, given the largest area of the latter. A rather enigmatic Argentinian sauropod is Chubutisaurus; found in the 1980s together with the meat-eating Carnotaurus, it was initially believed a late-surviving brachiosaurid, and some think it may be an intermediate form between brachiosaurids & titanosaurs rather than a proper titanosaur. Other examples of Argentinian (confirmed or putative) titanosaurs include Aeolosaurus, Andesaurus ("Andean lizard"), Campylodoniscus, Epachthosaurus, Ligabuesaurus, Neuquensaurus, Pellegrinisaurus, Rinconsaurus, Rocasaurus. However, titanosaurians have been found in most parts of the world. Both Hypselosaurus and Ampelosaurus come from France; the latter’s status as “the most complete French sauropod” has made it a sort of national celebrity since its find in the late 1990s. Hypselosaurus priscus (known since the early 1900) is far more fragmentary, but is famous in popular dino-books because is classically thought the source of some large fossil eggs found in the XIX century; they are reputed the biggest dinosaurian eggs ever found, and yet they’re only one foot long - not exactly like those man-sized objects seen in cartoons. Technically, they weren’t the biggest dinosaur eggs: the famous recently-extinct “Elephant Bird” from Madagascar laid the biggest known land-based eggs in the whole animal kingdom: up to 2 ft long. Aepisaurus, also found in Cretaceous France like the above, is known only from a humerus, and it's uncertain if it was a titanosaur or not.
The Ultimate Giraffe: Isisaurus
- Among titanosaurs which fell in the Titanosaurus-Wastebasket, one of the most astonishing is Isisaurus from India. With its thick neck, short tail and strongly sloping backbone, it was the most giraffe-like sauropod known to date, even more than the well-known brachiosaurids. Just as strange were its forelimbs, with extremely reduced "feet". The very fragmentary Aegyptosaurus and the more complete Malawisaurus (one of the few titanosaurs with fossil skull-material known) have received their name from the African countries they were found, Egypt and Malawi respectively; the aegyptosaur lived in Cretaceous Northern Africa near another famous Egyptian guy, Spinosaurus aegyptiacus; Malawisaurus was once confused with non-titanosaur sauropods, like Tornieria (a diplodocoid). Other African countries which have left important dinosaur remains are: Tanzania with the famous Tendaguru site full of Late Jurassic specimens - when the Tendaguru fossils were found, Tanzania was still a German colony: that explains why the famous "Brachiosaurus" (Giraffatitan) discovered here ended in the Berlin Museum. Other famed Tendaguru dinosaurs are the stegosaur Kentrosaurus, the small theropod Elaphrosaurus, and the diplodocoid sauropod Dicraeosaurus. Then there's South Africa, home for several Early Jurassic dinosaurs: classic examples are the prosauropod Massospondylus and the basal ornithischians Heterodontosaurus & Lesothosaurus, though technically the latest one was found in a tiny State surrounded by the South African Republic: the Lesotho indeed. Zimbabwe has left some dinosaurs as well (Vulcanodon, "Syntarsus"). Finally, several Saharan countries other than Egypt, like Morocco and especially Niger. Niger was home for the sailbacked ornithopod Ouranosaurus and several other Cretaceous animals: among them a strange sauropod, aptly called Nigersaurus (see further).
Emigrating in the USA: Alamosaurus
- And what about North America? Did any titanosaur live here, along with T. rexes and Triceratops? Yes, it did, but was the only one known: Alamosaurus, possibly an isolated migrant originally from South America. Even though it's known only from (again…) not-complete remains, its status of “the only one who met Tyrannosaurus rex in Real Life!” (and its “token sauropod” appearance as well, without any known armor) has made it the perfect Hand Wave for those artists/writers who have fun to portray Apatosaurus/Brontosaurus/Diplodocus/Brachiosaurus/Giraffatitan living side-by-side with Tyrannosaurus. Considering the extreme rarity of this eventuality, this would make Alamosaurus, not "Brontosaurus"/Diplodocus/"Brachiosaurus", the real Great-Stock sauropod.... Just as an example, the sauropod skeleton seen next to the Tyrannosaurus one at the end of the first Jurassic Park film has been labeled "Alamosaurus", but is more probably an Apatosaurus. Alamosaurus was found only in southwestern North America, while T. rex and Triceratops lived mostly farther north. There was some overlap between the two ecosystems, but only in a narrow area of Utah and Wyoming: thus, a battle between a T. rex and an Alamosaurus must have been a rare event. Extremely recent discoveries suggest that Alamosaurus may have been one of the largest sauropods, with fragmentary remains suggesting at animals equal or greater in size than Argentinosaurus.
Titanosaurs or Diplodocids?: Nemegtosaurus & Quaesitosaurus
- Two alleged diplodocoids were found in Late Cretaceous Mongolia in the 1970s: Nemegtosaurus and Quaesitosaurus, both known from one single Diplodocus-like skull. Since Late Cretaceous sauropods were titanosaurs, the question was: were they late-surviving diplodocoids, or just Diplodocus-like titanosaurs? In 2000, the discovery in Madagascar of Rapetosaurus, a very complete Late Cretaceous titanosaur with a clearly Diplodocus-shaped head, reveals the second option being the more likely.
Diplodocoids
Porcupine Dinosaur:
Bajadasaurus
- Described in 2019 at the end of The New '10s from incomplete remains (but already found in 2010, at the start of them), the dicraeosaurid sauropod Bajadasaurus pronuspinax ("forward-spined Bajada's lizard": Bajada is the Patagonian locality where it's been found) shows huge neural double-spines on its neck. They pointed forwards, not backwards like Amargasaurus. Found in Early Cretaceous Argentina like the latter and relatively small as well, its look was however even more striking than those of the amargasaur itself (found in year 1990), with even longer neck-spines. This animal might gain more attention in the future thanks to this "horned hairdo", which could have been for defence against giant predatory dinosaurs of the time. Like Amargasaurus we don't know however for sure if there was a "double sail" made of skin connecting the spines, or defensive horny sheaths, but Bajadasaurus describer has hypothesized the second thing.
Sauropod?: Brachytrachelopan
- Still another dicraeosaurid, Brachytrachelopan (lit. "short neck") from Late Jurassic South-America was even weirder than the spiky Amargasaurus and Bajadasaurus. Found in the 2000s, with its extremely shortened neck it didn't seem even a sauropod! Indeed, South America has gifted some other odd sauropods in recent years: the titanosaurian Bonitasaura ("beautiful lizard" in Spanish) had uniquely a horny beak put behind the frontal teeth. While Agustinia (originally called "Augustia") was thought to have had long, raised bony plates like a stegosaur, but these now appear to be misinterpreted normal bones. And in North America, Dyslocosaurus ("lizard in the wrong place") was believed to have had five claws on each rear-foot, unlike the typical three-clawed feet of every other sauropod. Returning to Brachytrachelopan, it's worth noting that the shortness of its neck was obtained not by diminishing the number of vertebrae, but extremely-shortening each of them — the exact contrary than the modern giraffe, that has the typical seven neck-vertebrae of every mammal but very elongated.
Saharian Longneck: Rebbachisaurus
- Other diplodocoids were still more primitive than the above: Rebbachisaurus ("Rebbachi lizard") from Cretaceous Sahara maybe still hadn’t a whip-like tail. This sauropod was found in several African countries, but its remains are sparse; once, it was even believed a brachiosaurid and not a diplodocoid. Some alleged Rebbachisauruses were described in South America, but now are classified in other genera within the Rebbachisaurids (ex. Limaysaurus). Another rebbachisaurid, Nopscaspondylus, was described in Argentina in 2007: it means "Nopsca's vertebra" from the European palaeontologist Franz Von Nopsca who first found its remains at the start of the XX century, and was one of the last-surviving diplodocoids, from Middle Cretaceous.
Hundreds of Teeth: Nigersaurus
- The family of the Rebbachisaurids also contains Nigersaurus from Niger, whose well-preserved skull shows strange grinding teeth. It also had the most teeth of any known saurischian: at any one time, there could be over five hundred teeth in its mouth - among dinosaurs only the ornithischian hadrosaurs had even more teeth in their mouths. In 2018 it was discovered that the legendary Amphicoelias fragillimus, known only from a single immense vertebra and long believed to be a gigantic diplodocid, was actually a member of the rebbachisaurid group, and now has been renamed Maraapunisaurus. Maybe the most basal rebbachisaurid is Histriasaurus from Croatia (Histria is indeed in Croatia, former Yugoslavia). Some sauropods are controversial if they were diplodocoids, or not: Haplocanthosaurus ("single-spine lizard") could be a more basal sauropod. Found as early as the 1900s, lived alongside the “stock sauropod trio” "Apato"-"Diplo"-Brachiosaurus in Late Jurassic North America, but is rarer and extremely less-portrayed. Also living along the latter were Dystrophaeus (described by Edward Cope) and the dicraeosaurid Suuwassea ("ancient thunder"). "Eobrontosaurus" ("dawn thunder lizard") was described by Bob Bakker in 1998 as a very Apatosaurus-like new diplodocid genus, but it was in the 2015 merged again in the officially resurrected "Brontosaurus". While Cetiosauriscus (Middle Jurassic Europe) despite its name meaning "similar to Cetiosaurus" was long not believed a basal sauropod like the latter but a true diplodocoid, even though recently it has been reclassified outside Diplodocoidea in a more primitive position within the sauropod evolution.
Titan or Atlas?: Atlantosaurus
- This dinosaur was the first sauropod described during the XIX century Bone Wars, see History of Dinosaur Discoveries. Many alleged Atlantosaurus remains have then revealed to belong to Apatosaurus/Brontosaurus, while the original one (a hard-to-classify diplodocoid) is very scanty. It was called Atlantosaurus ("Atlas Lizard": Atlas was the gigantic Greek god who kept the Sky with his arms, and origin of the name of the Geographical Atlas) by O. Marsh, after having named it "Titanosaurus" little time before; his archrival E. Cope noted that the name Titanosaurus was officially used few months before for the Indian sauropod today prototype of the Titanosaurians — hence the name-change. In old textbooks Atlantosaurus was often hugely oversized, ex. cited as "the biggest dinosaur ever": one of the earliest cases of exaggerations in non-scientific media. The similar-named Atlasaurus was another kind of sauropod, but found in Morocco in 1999 and not a diplodocoid but a primitive member of the sauropodian clade like Cetiosaurus, with rather complete remains. It owes its name, other than from its sauropodian size (15 m, but smaller than the classic Stock Sauropods) from the fact that Atlas was said living just in Morocco, where the Atlas Mountains are located; the Atlantic Ocean is so-called because Morocco has the vastest portion of its seashores just in this ocean (the remaining ones are in the Mediterranean Sea).
Macronarians
Starry Teeth: Astrodon
- While diplodocoids are abundant, brachiosaurids are much rarer. Most described species are fragmentary, and with their appearance unknown. We can mention, because of their historical relevance, Astrodon and Pelorosaurus. Astrodon ("starry tooth") is the first sauropod found in North America (even before the Bone Wars), but is known mainly from teeth; other incomplete remains found within the "wars" were once referred as "Pleurocoelus" ("hollow side"). Astrodon is traditionally considered a “small” sauropod about 10 m long, and lived in Early Cretaceous along Deinonychus and the much larger Sauroposeidon. Some analyses, however, suggest Astrodon is not a brachiosaurid, but is closer to titanosaurs. Curiously, the synonym "Pleurocoelus" used to be described as a much bigger brachiosaurid than Astrodon.
The 2nd-described Sauropod: Pelorosaurus
- On the other hand, the English Pelorosaurus was probably as big as Brachiosaurus, but like Astrodon (and most non-stock brachiosaurids), lived in Early Cretaceous as well, and is very scanty. Some have depicted Pelorosaurus with an armored back like that of the titanosaur Saltasaurus, but it's dubious if it really had it. Pelorosaurus was the second (1850) sauropod described after Cetiosaurus, and lived together with Iguanodon, Hypsilophodon, and Baryonyx. Since sauropods were virtually unknown at the time the pelorosaur's find strongly astonished its describer, to the point he gave it its name meaning monster lizard. Later, Pelorosaurus was treated as a Waste-Basket taxon for undetermined European sauropods: among these former “pelorosaurs” (all dubious) we can mention "Dinodocus" from Early Cretaceous (not a Diplodocus relative as it seems), and "Gigantosaurus" (not Giganotosaurus), which lived in Late Jurassic earlier than the real Pelorosaurus.
Brachiosaur Relative?: Bothriospondylus
- From the same period of "Gigantosaurus" comes another little-known European sauropod, Bothriospondylus, often considered a brachiosaurid in the past: even though is known since the early 1900, it has not fallen in the "pelorosaur wastebin" — but to compensate, it has been treated as a small "wastebin" on its own, assigning to it some fragmentary sauropod remains from Madagascar, now known as Lapparentosaurus. Also known since the late 1800 but equally not-fallen in the pelorosaurian wastebin are Chondrosteosaurus ("cartilage-bone lizard") and Macrurosaurus ("big tailed lizard"), both from England; the latter was an Early-Cretaceous relative of titanosaurs known only from 40 tail vertebrae. In Portugal, a formerly-believed species of Brachiosaurus is now labeled Lusotitan ("Portuguese titan"). Once, "Dystylosaurus" was also considered a brachiosaurid, but today is classified within the diplodocid genus Supersaurus.
Jurassic or Cretaceous?: Euhelopus
- Together, Brachiosaurids, Camarasaurids, Titanosaurians, and others make the Macronarians, one of the two great sauropod subgroups together with Diplodocoids. One example of macronarian which do not pertain to the aforementioned subgroups is Euhelopus zdanskyi. The first-found non-fragmentary sauropod in China (and one of the very first found Chinese dinosaurs, in the 1920s), it had long neck and short tail which made it looking like a miniaturized Mamenchisaurus. Indeed, Euhelopus ("good foot for swamps", originally called "Helopus", "foot for swamps") was once believed related with the mamenchisaur; but now is considered a more evolved sauropod, closely related with titanosaurians. Euhelopus is the most "classic" among Asian Early Cretaceous sauropods (other less-known examples are Chiayusaurus and Mongolosaurus), even though some old sources wrongly claim it was Late Jurassic, thus possibly living near Mamenchisaurus. Many other Chinese sauropods, such as Tienshanosaurus and Klamelisaurus from Xinjiang, "Damalasaurus" from Tibet, Abrosaurus, Protognathosaurus, Sanpasaurus & Zigongosaurus from Szechwan, and "Oshanosaurus" from Yunnan, really hailed from Jurassic. On the other hand, the Euhelopus-relative Phuwiangosaurus was actually Early-Cretaceous, but was found in Thailand instead of in China. The euhelopus could have been the model for Prehistoric Park’s “titanosaurs” seen in the early Cretaceous episode about "Dino-birds".
Little Giant: Europasaurus
- Another sauropod, the short-named Erketu from Late Cretaceous Mongolia, despite its comparatively small size is believed to have had the longest neck respect-to-the body of any sauropod - the polar opposite of the diplodocoid Brachytrachelopan, which has the shortest neck for any known sauropod. Cathetosaurus from Late Jurassic USA was originally described by James Jensen (the Supersaurus discoverer) in the '80s as the most apt sauropod to rear up on its hindlegs, but has since then often classified as a simple species of the well-known Camarasaurus. South-African Early Cretaceous Algoasaurus, found by Robert Broom in early 1900, was also once believed a camarasaurid, but is known only from a leg-bone. Lourinhasaurus from Portugal, on the other hand, seems a true camarasaurid. "Nurosaurus", a yet-undescribed sauropod found in 1991 in Inner Mongolia (province of China), has revealed to be one of the biggest Asian sauropods with its 25-meters-long body, rivalling the famous Mamenchisaurus. Among the other hard-to-classify macronarians, there is also the curious case of Europasaurus. Found in Europe, it lived in the Late Jurassic islets in which is today Germany; in spite of being one of the smallest (6 m) sauropods ever, it should have appeared a true giant to its two neighbors Compsognathus and Archaeopteryx. Europasaurus is not the only case of insular dwarfism among sauropods however: another case is the already-mentioned titanosaur Magyarosaurus from Romania, which was about the same size.
Basal Sauropods
Club-Tailed Sauropod: Omeisaurus
- Shunosaurus lived alongside members of a mostly Asian sauropod subgroup, the Mamenchisaurids, which included other kinds other than the namesake Mamenchisaurus, the best-known of them has been Omeisaurus. This one ("Omei lizard") lived in the Late Jurassic like the mamenchisaur, and like the latter was described by the father-of-Chinese-paleontology Yang Chung Chien in the 1940s. Smaller than Mamenchisaurus (20 m long) but with a very long slim neck and comparatively short tail, Omeisaurus looked like a smaller version of it, but is known to have had a tail-club very similar to that of Shunosaurus (but without the "thagomizer"). Several confirmed species are known from Omeisaurus (an unusual thing among dinosaurs as a whole) and yet this dinosaur has not been a common sight in books. Other mamenchisaurids were more generic-looking, for example the medium-sized Tienshanosaurus (also described by Young Chung Chien from good remains including even some egg fragments), while the equally middle-sized Datousaurus and the very small Bellusaurus were considered mamenchisaurids but probably weren't. All these animals were found in China, but one mamenchisaurid appears to be present in the African Tendaguru formation.
Archaic Argentinian: Patagosaurus
- Outside Asia, one of the most relevant primitive sauropod has been Patagosaurus from Patagonia and, more recently discovered, Jobaria from North Africa. Both were Middle Jurassic, even though the latter was believed Cretaceous, thus a late-surviving form. Patagosaurus is still the most well-known sauropod from Jurassic South America; known from eight adult individuals and one juvenile, was very similar to Cetiosaurus in shape and size. Indeed, most generic-looking basal sauropods used to be put in the "Cetiosaurid" family, but this was actually an artificial assemblage. Others South-American Jurassic sauropods include Amygdalodon ("almond-tooth") and Volkheimeria (named after a German scientist).
Spine-Bearer: Spinophorosaurus
- Similar to Shunosaurus but not related, Spinophorosaurus (meaningfully "spike-bearing lizard") discovered in 2009 in Middle Jurassic Africa had also a similar armored tail, with a thagomizer but not a club. It was probably even more primitive than Shunosaurus, and like the latter, is one of the best scientifically-known early sauropods today. Interestingly, its first two skeletons were digitally replicated after being brought in Europe, making Spinophorosaurus the first sauropod to have its skeleton 3D-printed.
Primitive Colossus: Turiasaurus
- But the most spectacular basal sauropod is the Spanish Turiasaurus described in 2006 from the boundary between Jurassic and Cretaceous (this was a late-survivor); 30 m long and massively-built, it's the biggest known basal sauropod, with a similar size of an Argentinosaurus and other colossal titanosaurians! It has recently become the prototype of its own lineage of basal sauropods, the Turiasaurians, which include other smaller sauropod, namely the Spanish Losillasaurus, the Portuguese Zby, and others. Aragosaurus ("Aragon lizard"), also from Spain, is of uncertain classification: it was originally considered a camarasaurid, but could be another turiasaurian as well.
Long-necked Aussies: Rhoetosaurus & Austrosaurus
- Sauropods have been found almost everywhere, Land Down Under as well (but still not in Antarctica, unlike "prosauropods"). But are little-known there. Austrosaurus and Rhoetosaurus are two rarities in books, less-frequent than smaller Australian dinosaurs like Leaellynasaura, Minmi, Muttaburrasaurus, or even the alleged “dwarf allosaur”; this can be justified though, given their scarce remains. Rhoetosaurus (its name comes from a Greek giant) still remains one of the few known Australian dinosaurs from the Jurassic (another is the enigmatic theropod Ozraptor: most known aussie dinos were Early Cretaceous). It is a basal sauropod maybe related with Cetiosaurus, or maybe even more primitive. On the other hand, Austrosaurus ("southern lizard") was a typical Early Cretaceous dinosaur; Late Cretaceous dinosaurs are still unknown from Australia. It is more incomplete but more peculiar than Rhoetosaurus, having unusually-long forelimbs; once, Austrosaurus was believed a primitive late-surviving non-diplodocoid / non-macronarian sauropod; today is classified as a titanosaur relative. Very recent additions in the Australian sauropod list are Australotitan, Diamantinasaurus, Savannasaurus, and Wintonotitan. The first one ("southern titan"), described only in 2021, was a titanosaur and is now the biggest known Australian dinosaur, while Savannasaurus is the most complete Australian sauropod.
The Indian Precursor: Barapasaurus
- All the sauropods already listed in this page were "Eusauropods" ("real sauropods"). Yet, there were even more basal sauropods other than these: Vulcanodon and Barapasaurus are the two classical examples. Both from Early Jurassic, they still had “prosauropod” traits in their skeletons, but their external shape was already sauropodian, with pillar-like limbs and elephant-like feet. Vulcanodon was very small for a sauropod — 6 m long, less than a plateosaur but still much bigger than most other sauropods predecessors. On the other hand, Barapasaurus ("big-legged lizard", not to be confounded with Barosaurus) was the first known sauropod to have reached the classic huge sauropodian size: 18 m long, like Camarasaurus or Cetiosaurus. It’s also one of the few dinosaurs from India, while the vulcanodont was Southern African and lived alongside the well-known prosauropod Massospondylus.
The First Steps
- True sauropods started their evolution in Early Jurassic. Before, only sauropod predecessors like Plateosaurus or Thecodontosaurus existed. Examples of other Early Jurassic sauropods (all small-sized like Vulcanodon) include Ohmdenosaurus from Germany, Tazoudasaurus from Morocco, Kunmingosaurus and Zizhongosaurus from China, and Kotasaurus from India. Among them there were some of the smallest true sauropods known, some no more than 4 m long, less than many "prosauropods". Isanosaurus from Thailand was quoted as a Late Triassic animal and described as the "most ancient true sauropod" when it was found in 2000, but could be Late Jurassic instead and is very fragmentary.
