FORGOTTEN GIANTS, #2: Argentinosaurus

It has been a LONG time, dino-fans. But after SVP 2010, its aftermath, writing and working on tons of other projects, I thought I'd show you all something that's already been making the rounds on DeviantArt.

My second installment of the Forgotten Giants series, Argentinosaurus!


Argentinosaurus huinculensis is widely considered to be the biggest dinosaur. Though Amphicoeliasfragillimus would have been far larger, and even today, Puertasaurus is the biggest dinosaur known from currently existing remains, that still doesn't reduce the fact that Argentinosaurus still holds many records.

* The largest femur currently known
* The tallest dorsal vertebrae currently known
* The longest tibia currently known (no, Bruhathkayosaurus doesn't count. Here's why.)
* Possibly the largest sacrum ever discovered
* The largest replica/speculatively sculpted fiberglass skeleton mount anywhere (there's one copy in the Fernbank Museum, another in Germany's Senckenberg Museum, and another at Museo Carmen Funes in Plaza Huincul, near the site of the dinosaur's discovery).
* The longest dorsal column of any titanosaur
* The largest (and possibly only) dinosaur to have a museum built on-site specifically to house its remains
* The biggest dinosaur named for a country

So it's almost a forgone conclusion that this giant would be #2 in my series. It's not really "forgotten" at all, but it's still a very important member of the titanosauria, and still not very well-understood. The remains uncovered and described by Dr. Jose Bonaparte and Dr. Rodolfo Coria are pretty limited, but the size of them is astounding. Vertebrae over a meter tall. A femur 8 feet long. And hips as wide a car.

Within a few years it had become an international sensation. Finally, Ultrasauros was out and Argentinosaurus was the new biggest dinosaur. By the late 90s, its name was well known, and it became the subject of a number of long-forgotten TV specials with badass music but dismally high narrator turnover rates.


Ahh yes, the 90s. Good times...

Argentinosaurus is today still famous as the "biggest dinosaur" despite Supersaurus being longer, Sauroposeidon being taller, and the legendary Amphicoelias fragillimus being far longer and far heavier. Even since 2005, when the even more massive Puertasaurus was discovered, Argentinosaurus is still the iconic "record holder" in the eyes of the public. So even though it's pretty popular and far from forgotten, it's still a very important titanosaur, so you knew I was going to give it the Paleo-King treatment sooner or later!

However, there was a bit of a challenge - though huge, the known bones of Argentinosaurus comprise only a small portion of the skeleton. Several dorsal vertebrae, a tibia, a referred femur shaft, a partial sacrum, parts of the ilia and a fragment of pubis. There's also a second referred femur which may be from Argentinosaurus but I've never seen it figured.

This scarcity of fossil remains hasn't stopped people from trying to fill in the huge gaps. The Fernbank Museum's Argentinosaurus mount in Atlanta, Georgia, which is made of mostly speculative fiberglass models along with a few casts of the original bones, is one such attempt. But it's got a host of mistakes in the speculative parts.





These three mounts are all identical, and even have similar poses, but are photographed from different angles. See if you can find the following errors in them (there may be even more that I didn't catch):

* Abnormally angular nasal arch
* Lower jaw looks strangely too much like that of Giganotosaurus - huge side hole and all!
* Teeth are far too few and thin, appear to be made of wire
* Neck is too horizontal (probably a result of the designers and welders reading too much Kent Stevens...)
* Most neck vertebrae are just clones/recasts of one another; three in a row identical, then the next three...
* Cervical ribs are drooping down at the ends instead of overlapping snugly in double rows along the base of the neck.
* Ribs are excessively deep in the chest region to shorten far too rapidly as you go back to the hips - a 'triangular pan-pipe' rib cage profile not seen in any sauropods.
* Ilia are curved inward toward the backbone at their front tips, big mistake! In titanosaurs (and all macronarians for that matter) they are curved OUT. Titanosaurs had a wide belly, flared-out hips make sense. For that matter, the rib cage is also a bit too narrow!
* Sacrum is missing large portions of the front two sacral ribs (the original fossil was missing them too -why didn't the preparators account for this and reconstruct the missing portions?)
* Sacrum is not fused to the ilia - in fact there are huge gaps separating it from them. The reason for these garish gaps can only be guessed at.
* The radius and ulna are improperly aligned in both arms. They should be one in front of the other, not side by side like the tibia and fibula. A little knowledge of vertebrate anatomy could go a long way here...
* The hands lack phalanges and thumb claws. The reasons for NOT getting rid of them are actually quite strong for titanosaurs, especially basal ones like Argentinosaurus. Suffice it to say that even derived titanosaurs like Diamantinasaurus had thumb claws - they just don't get preserved in most titanosaur hands because of the loose cartilage connections in the phalanges, which dessicated easily, allowing the thumb claws to be washed away.
* The feet are far too large and have an excessive fourth claw. This is not found on most sauropods.
* The metatarsals and toes are arranged in an almost linear pattern, rather than the semi-columnar, circular pattern that they would normally articulate in. And yet we criticize Chinese museum workers for making the exact same mistake with their sauropods... sheesh.
* The ankles have an extra "squashed mound of dough" bone beneath the real ankle bones, the Astralagus and the Calcaneum (both of which are too large anyway). This squashed mass is not a real bone at all, nor is it based on anything found in real fossils. One can only assume it represents ossified cartilage, but the ankle cartilage of sauropods NEVER ossified!



Those awful feet ! Linear arrangement of the digits, extra 4th claw, no vestigial 5th phalanx, 4th metacarpal is mysteriously thicker than the 3rd one, ankle bones WAY too big to match the tibia and fibula, and the feet are practically the size of Texas for a dinosaur that was only 110 ft. long!
You could probably sleep under those feet at night!

As for illustrations of Argentinosaurus.... some are great, some are okay, and most are downright terrible. The terrible ones are too many to list. But here is a sample of some of the better ones out there:









But what of the scientific illustrations? I mean actual skeletal diagrams...

Well, there are only really two. Greg Paul's, and Ken Carpenter's....

It is not a mistake that Greg Paul's skeletal shows fewer bones than Ken Carpenter's - it was done earlier, just one year after after Bonaparte and Coria's description paper came out (it didn't have diagrams of a couple of the vertebrae, or the femur shaft, which was dug up and referred to Argentinosaurus later). Though why he left out the sacrum is a mystery, as it was in the original paper.

The main difference aside from the bones, is obvious - the shape. Carpenter's version has much shorter arms and a very short thing neck. It's almost embarrassingly small... it's basically a scaled up Saltasaurus! In 2006 there seems to have been a trend towards "re-sizing" Argentinosaurus. Paul's version was considered by many in the field to be too brachiosaur-like, with its long vertical neck and tall arms. Carpenter proposed a radical re-interpretation of Argentinosaurus based on very late, derived titanosaurs like Saltasaurus - which reduced the length of Argentinosaurus to only about 80-90 feet or so. But this revision is not as reliable as it seems. Saltasaurus (which lived in the Maastrichtian epoch) was one of the last titanosaurs to evolve, millions of years after Argentinosaurus (Cenomanian epoch) was long extinct. It's not very likely that the early titanosaurs looked exactly like the last ones. Additionally, Saltasaurus was a small species, far smaller and shorter than Argentinosaurus, and specialized for low-grazing like a diplodocid or dicraeosaurid. The skulls of other small, short-necked titanosaurs like Bonitasaura bear this out - the teeth have become crowded in the front of the mouth and very thin, much like Diplodocus, in a wild case of convergent evolution. But something as huge and massive as Argentinosaurus must have been a treetop feeder - and it would have needed a very long neck. This is true of most if not all of the big basal titanosaurs. But that doesn't mean all of the late stage saltasaur-type titanosaurs were little short-necked grazers. There were some, like Alamosaurus, that had far longer necks, longer arms, and grew much larger than Saltasaurus. Very long necks and long arms didn't die with Brachiosaurus - they survived well into the end of the Cretaceous.





So maybe using a "brachiosaur-like" model for Argentinosaurus isn't so bad after all. Monster necks seem to have been the rule rather than the exception in titanosauriforms both before and after its time. And Greg Paul's version of Argentinosaurus doesn't look all that much like a brachiosaur. It's something different. It's actually not copied from any other animal the way Carpenter's version is copied straight from Saltasaurus.

I had a hunch that Paul's version was generally correct. But that long whiplash tail bugged me. It's too diplodocid-like, and even the whip-tails wound on later titanosaurs weren't so thin and limp at the end. Also, Ken Carpenter's version does have two major advantages that Greg Paul's doesn't - it's got ALL the bones currently known (though it heavily distorts their shapes) and it gives an idea of the shape of the pelvis. It's also got a bit of pubis, which wasn't mentioned in the original description paper, but which may be present in some grainy internet photos. This was the clue for dissecting the actual number and shape of the missing bones.


The original bones on display in Plaza Huincul, Argentina.