Prehistoric Life/Dinosaurs/Sauropods

A dino-sized injustice: Camarasaurus

• Which is the most common sauropod in the USA, Apatosaurus, Brachiosaurus, or Diplodocus? None of them. It was Camarasaurus. This dinosaur was as enormous as the former, and shared their same habitat in which other two popular dinosaurs lived, Stegosaurus and Allosaurus; and yet, when was the last time you’ve heard “Camarasaurus” in a film/cartoon/comic? Even the famous Speculative Documentary Walking with Dinosaurs has totally ignored it, preferring its stock cousins instead. The misfortune of Camarasaurus is probably due to not detaining any size-record among sauropods: it has never been either “the longest” like Diplodocus, or “the tallest/heaviest” like Brachiosaurus. Discovered during the Bone Wars, Camarasaurus is considered by some a rather unsauropod-like sauropod, because of its relatively large head and its much-shorter neck compared to most other sauropods. It tended to be confused with the so-called “Brontosaurus” in the past, because the classic brontosaur portraits have a round head and a short, blunt tail, just like Real Life camarasaurs. However, Camarasaurus was more related to Brachiosaurus than to Apatosaurus. Both the brachiosaur and the camarasaur had short, boxy skull with wide nasal openings, a nasal crest, and relatively large teeth which bordered the whole jaws - the Diplodocus and Apatosaurus skull was longer and flatter with peg-like teeth only on the jaw-tips. The four legs of Camarasaurus were about the same length, and its back was perfectly horizontal and perhaps even a bit taller on the shoulders: Apatosaurus and Diplodocus has shorter forelimbs than hindlimbs, and their back had a convex silhouette with the tallest point on the hips.

The longest neck: Mamenchisaurus

• What is the thing that has really made sauropods the most iconic plant-eating dinosaurs? Their size, useless to say. But there are few doubts that their unbelievably long necks have done their part, too. But wait: if you think Brachiosaurus and Diplodocus have disproportionately vast necks, is only because you’ve never seen their Chinese cousin: Mamenchisaurus. The latter’s neck was so long that, if the animal would be still alive today, we could see it drinking some water from a lake with its forelimbs placed 12 m (40 ft) or even 15 m (50 ft) from the shore! In other words: the neck of Mamenchisaurus was longer than a whole T. rex was from nose to tail. This record has made Mamenchisaurus one of the most famed sauropods as well as one of the most classic Chinese dinosaurs. ^[1]. Discovered in 1954, Mamenchisaurus lived in the same age of the stock sauropods (Late Jurassic). Initially believed a close Diplodocus relative, now is thought a more archaic kind of sauropod which incidentally reached a similar shape, though with a much shorter tail ending with a small club. Since the head of Mamenchisaurus has long been unknown, the most classic portraits show it with an inaccurate Diplodocus-like head; actually Mamenchisaurus head was more similar to Camarasaurus. In short, the polar opposite of what has happened to the allegedly boxy Apatosaurus head. To date, the only significative apparition Mamenchisaurus has made in pop-culture was a extremely brief cameo in Jurassic Park 2. It was unidentified and unnamed, maybe the only dinosaur in the Jurassic Park film-series that has not become Stock after that. As it seems, four pop-cultural sauropods are just too many.

Hearts, hearts everywhere: Barosaurus

• Overshadowed by Awesome seems a common trope among dinosaurs. We see a dinosaur, remain struck by its awesomeness… but later, another similar yet even cooler dinosaur takes its place in our mind. Barosaurus could be an example. 8/9 m long, its neck was one of the longest in the whole Animal Kingdom, but is definitively overshadowed by the 12/15 m long neck of Mamenchisaurus (as well as that of the brachiosaurs). Discovered in USA at the end of the Bone Wars, Barosaurus was the closest relative of Diplodocus, and lived as well in Late Jurassic North America; some possible remains from Africa are also known, but are fragmentary and undiagnostic. Barosaurus was virtually identical to Diplodocus except for its shorter tail counterbalanced by the longer neck. Its was one of the longest sauropods, only a bit shorter than a diplodocus. Barosaurus means “heavy lizard”: though apt for a sauropod, is not totally appropriate. Having the same slender frame of Diplodocus, the barosaur weighed less than other sauropods. Its lower notoriety is probably due to the fact Barosaurus remains are less abundant than the Diplodocus ones. However, Barosaurus has gained more fame when a barosaur skeleton was mounted in the American Museum of Natural History in the 1980s. This skeleton is the dino-star of the museum, being mounted erected on the hindlimbs and the tail; 15 m tall, is shown defending its youngster from an attacking Allosaurus. In the same years, one bizarre suggestion was made about its physiology: with such a long neck, Barosaurus may have had eight hearts to pump blood up to its lofty head. There isn’t any evidence for this idea, which is now generally discarded as “weird fantasy”.

The armored brontosaur: Saltasaurus

• When we think about “armored” dinosaurs, our mind automatically goes to things such as Stegosaurus, Triceratops, Ankylosaurus. Thus, if you are a layman, you could be astonished if we tell you that there was also an armored sauropod. Scientists themselves were surprised when such an animal was discovered in 1980 in the Argentinian province of Salta: they called it Saltasaurus (not “Saltosaurus”, please). It walked around 80 million years after the overused "three stock band", almost managing to see the comet. Saltasaurus armor was different-looking than Ankylosaurus armor. It had no spikes, and was made by several small bony scutes of different size, covering all the upper parts of its torso like a mosaic. Though apparently much lighter than an ankylosaur’s, it would have been enough to defend the sauropod against predators like the contemporary “horned” Carnotaurus. The scientific importance of Saltasaurus raised up even more after the discovery (made at the end of the 1990s) of a fossilized breeding-site full of nests and hatchlings, the very first known from a sauropod. These remains were attributed to Saltasaurus, but we are not sure if they pertain to its genus. Saltasaurus is also a member of that subgroup of sauropods called titanosaurs (see below): since its discovery, armor plates of several other titanosaurs have since been found, although more incomplete. However, Saltasaurus was considerably smaller than many other sauropods (it was only 12 m long and not much heavier than an elephant); and, not counting the bony plates, its shape was that of a generic sauropod. This might partially explain why, despite its Badass-look, Saltasaurus has remained a non-fictional animal unlike Carnotaurus.

A whale of dinosaur: Cetiosaurus

• Which were the biggest animals ever, whales or dinosaurs? Hard question, depends on what criterium you want to use. Cetiosaurus, the first sauropod ever described, just means “whale-lizard”. But this is not a mere reference to its huge size; it was literally believed a whale-thing at one point. First found in 1842 in England slightly after Richard Owen coined the word “dinosaur”, its first remains were so incomplete that Owen couldn’t believe such a heavy animal could live on land. Since limb bones were missing, he thought the owner was a non-dinosaurian marine reptile (remember sea-reptiles were already very well-known at the time). When the limb bones were discovered several decades after, the familiar image of an elephantine “reptile” with long neck and tail came to light. Though not a Wastebin-taxon like Megalosaurus, Cetiosaurus could thus be seen as its sauropodian equivalent - incidentally, lived just alongside Megalosaurus in Middle Jurassic Europe, but has been found in North Africa too. Cetiosaurus has been the archetypical “basal” sauropod, and lived before the Stock Trio. Among the cetiosaur's primitive traits, it had compact vertebrae instead of hollow - cavities in the backbone is a typical feature of more evolved sauropods like Apatosaurus, Diplodocus, Brachiosaurus and Camarasaurus (the latter’s name just meaning lizard with cavities). Unfortunately for Cetiosaurus, these sauropods were discovered in North America just in the period of the former’s correct interpretation, Their bigger size and/or their greater completeness meant Cetiosaurus was progressively put under the table. Making things worse, the cetiosaur has also a very generic look with no external traits that would make it recognizable. In short, this “whale of dinosaur” was predestined to become an only-book animal.

Titanic lizards: Titanosaurus, Alamosaurus, Hypselosaurus, and Opisthocoelicaudia

• “Titanosaur” is a often-heard name in documentaries, books and sometimes in pop-media: what is it exactly a titanosaur? Well, it has actually two meanings. The more strict one indicates a precise genus of Late Cretaceous dinosaur, Titanosaurus, the first sauropod discovered in India (and Asia), in year 1877. Ironically, it’s actually is one of the most fragmentary sauropods, known only from few vertebrae and some other material, but was treated as one of the two most classic dinosaurian “wastebins” together with “Megalosaurus”: 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. They were a very abundant and widespread dinosaur group in Cretaceous, expecially the Late one; here we list only some noticeable examples. There were not only giants like Argentinosaurus, Paralititan, or Antarctosaurus (the latter is known since the start of the XX century, hence its generic name “Southern Lizard”). There was also an animal like Magyarosaurus, a dwarf sauropod only 6 m long, which reduced its size to survive in small European islands. Most titanosaurs, however, were far from these extremes. The armoured Saltasaurus and the almost unutterable Opisthocoelicaudia were 12 m long. Ironically, despite the high number of described species, titanosaur remains are very scant. Just as an example, Opisthocoelicaudia from Late Cretaceous Mongolia is considered one of the most complete, with well-preserved body, limbs and tail… but its head and neck are unknown. Even though most titanosaurian remains are from South America (expecially Argentina), they 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. Hypselosaurus is far more fragmentary, but is famous 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. ^[2]. Among titanosaurs which fell in the Titanosaurus-Wastebasket, 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. 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 a isolated migrant originary from South America. Even though is 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) has made it the perfect Hand Wave for those artists/writers who have fun to portray Apatosaurus and Tyrannosaurus living side-by-side. Considering the extreme rarity of this eventuality, this would make Alamosaurus, not “Brontosaurus”, the real Great-Stock sauropod...

Diplodocus’ kin: Dicraeosaurus, Amargasaurus, and Rebbachisaurus

• Diplodocus (and Apatosaurus of course) had many relatives. Not only some real or alleged “biggest dinosaurs ever” (Supersaurus, Amphicoelias), but also many other smaller, usually more primitive animals: Dicraeosaurus for example. Found in the famous Tendaguru deposit, it’s the smallest member of the classic Late Jurassic African Sauropod Trio (the other two have usually been called “Barosaurus” and “Brachiosaurus”, but they probably aren’t). With its short, Apatosaur-like neck and a long, Diplodocus-like tail, Dicraeosaurus could have had a ridge on its back, but this is not sure. His South American Early Cretaceous relative, Amargasaurus, surely had this. Its pairs of neural spines which arose from its neck perhaps substained a sail, or maybe were covered in keratin, making them true spikes for defense. Still another relative, the recently-discovered Brachytrachelopan (also South American but Jurassic) was even weirder; with its extremely shortened neck, it didn't seem even a sauropod! ^[3] Other diplodocoids were still more primitive than the above: Rebbachisaurus from Cretaceous Sahara maybe still hadn’t a whip-like tail. Its family also contains Nigersaurus, whose well-preserved skull shows strange grinding teeth. Some sauropods are controversial if they were diplodocoids, or not: Haplocanthosaurus could be a more basal sauropod. It 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 was Eobrontosaurus, a very Apatosaurus-like diplodocid which has partially resuscitated “Brontosaurus” in the official dinosaur list. Finally, two examples from Late Cretaceous Mongolia: Nemegtosaurus and Quaesitosaurus (maybe one and the same), both known from one single Diplodocus-like skull. Since Late Cretaceous sauropods were titanosaurs, the question is: 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.

Brachiosaur’s kin: Astrodon, Pelorosaurus, and Euhelopus

• While Diplodocoids are abundant, Brachiosaurids are much rarer. Most described species are fragmentary, and with their appearance unknown; take Sauroposeidon as example. We can mention, because of their historical relevance, Astrodon and Pelorosaurus. The former is the first sauropod found in North America (even before the Bone Wars), but is known mainly from teeth; it’s thought a “small” sauropod which lived in Early Cretaceous along Deinonychus and .Utahraptor. The much bigger Pelorosaurus (like most non-stock brachiosaurids, lived in Early Cretaceous) was the second sauropod described from Europe, and lived together with Iguanodon. Being its remains very scanty, it too was treated as a Waste-Basket taxon like Titanosaurus: one of these former “pelorosaurs” is the dubious but coolly-named "Gigantosaurus" (not Giganotosaurus). Together, Brachiosaurids, Titanosaurs, Camarasaurus and others make the Macronarians, one of the two great sauropodian subgroups together with Diplodocoids. Another macronarian which deserve a mention is Euhelopus. The first-found sauropod in China, similar to a miniaturized Mamenchisaurus, it could have been the model for Prehistoric Park’s “titanosaurs”, being the most classic among Asian Early Cretaceous sauropods.

Nobody's kin: Shunosaurus, Barapasaurus, and Vulcanodon

• Not every sauropod is either Diplodocoid or Macronarian. Many were more primitive than both. Cetiosaurus and Mamenchisaurus have already been mentioned: another relevant basal sauropod is Shunosaurus, from Chinese Middle Jurassic. Rather small (10 m long) and short-necked, it’s worthy of note for two things: its bony-club on its tailtip surrounded by four short spikes, resembling a combination between a Stegosaurian and Ankylosaurian tail; and the fact that, with its 20 or more skeletons known, Shunosaurus is one of the most common sauropod in fossil record, rivalling Camarasaurus. The shunosaur pertains to a Asian sauropod subgroup which included also Mamenchisaurus and another very similar animal, Omeisaurus (several species are known from the latter, and yet is not a common sight in books). Outside Asia, primitive sauropods include Patagosaurus from Patagonia and Jobaria from Africa – both Middle Jurassic, even though the latter was believed Cretaceous, thus a late-surviving form. Yet, there were even more basal sauropods other than these: Vulcanodon and Barapasaurus are two main examples. Both from Early Jurassic, they still had “prosauropod” traits in their skeletons, but their external shape was already sauropodian, with pillar-like limbs. While Vulcanodon (whose strange name means “volcano tooth”) was very small for a sauropod (6 m long, less than a plateosaur), Barapasaurus (not to be confounded with Barosaurus) was the first known sauropod to have reached the classic huge sauropodian size (18 m long). It’s also one of the few dinosaurs from India, while the vulcanodont was Southern African and lived alongside the well-known prosauropod Massospondylus.

A few longnecks more: Atlantosaurus and Australian sauropods

• Sauropods have been found everywhere, Land Down Under as well. But are little-known there. Austrosaurus and Rhoetosaurus: are two rarities in books, less-frequent than smaller Australian dinosaurs like Leaellynasaura or even the alleged “dwarf allosaur”; this can be justified though, giving their scarse remains. An almost-forgotten-today but very-important-once sauropod is "Atlantosaurus" (“Atlas lizard”); the first sauropod discovered within American Bone-Wars, but largely based on Apatosaurus remains, while the original "Atlantosaurus" is so incomplete to be regarded dubious genus. Our "Atlantosaurus" used to ben often cited in old books as the biggest creature ever appeared on Earth: one of the very first examples of dinosaur-related sensationalism. A tradition that still continues today: see an exhaustive list in the Stock Dinosaurs page.

1. ↑ It’s worth noting, however, that the classic record of “Whoa the longest-neck!” is now disputed now by the fragmentary Sauroposeidon
2. ↑ Technically, they weren’t the biggest dinosaur eggs: the famous recently-extinct “Elephant Bird” from Madagascar laid the biggest known eggs in the whole animal kingdom: up to 2 ft long.
3. ↑ Indeed South America has gifted many odd sauropods in recent years: Agustinia had long, raised bony plates very Stegosaur-like. Bonitasaura had uniquely a horny beak put behind the frontal teeth.