Feb. 8th, 2011

davegodfrey: South Park Me. (Default)
When I was a lad I read every dinosaur book I could get my hands on. And this being 20+ years ago much of what I read then is now out of date. Pterosaurs are now always shown as furry, when then there were somewhat brief dismissive mentions of this "Hairy Devil" from the USSR. Sauropods have been rescued from near-certain death by suffocation from snorkeling about in lakes. (The pressure from water at this depth would have crushed their lungs and irreparably damaged their hearts had they tried this. The German physiologist Robert Stigler tried breathing through a six-foot tube and suffered heart damage as a result.)

But one thing was almost universal. Sauropods weren't doing very much in the Cretaceous other than dying out. From their heyday in the Late Jurassic, when Diplodocus Apatosaurus and Brachiosaurus stumped about the place, by the Late Cretaceous the world was full of horned dinosaurs, flamboyantly crested hadrosaurs, spiky club-tailed ankylosaurs and the like. Occasionally you'd find mention of Alamosaurus, a 21 metre 30 tonne sauropod from New Mexico. But it was usually in the "A-Z" type books and tended to get three lines if that.

Now it turns out that a fair bit of this is the result of historical bias. The USA and Canada were the scene of some very intensive collecting during the 19th and early 20th centuries, followed by Roy Chapman Andrews expedition to Mongolia. The rest of the world didn't get much of a look-in. Which is a shame, because in the rest of the world there doesn't seem to have been much of a change. Hadrosaurs and ceratopsians were largely an Asian and American specialisation, and in North America the sauropods seem to have died out completely for 30 million years before Alamosaurus turns up to see out the Cretaceous. But in South America, for example, the sauropods thrived, and grew to even bigger sizes than the Jurassic Morrison Formation ones that everyone knows (Brachiosaurus, and its African cousin Giraffatitan)- despite being relatively poorly known (and in some cases poorly measured) Futalognkosaurus, Argentinosaurus and Puertasaurus were among the largest dinosaurs known, dwarfed only by the semi-mythical Amphicoelias fragillimus.

The impression that I got all those years ago was that this dinosaur was small (relatively), and not exactly common. Which is utterly and completely wrong. Alamosaurus crops up all over the place, and is a very common dinosaur. And while the size estimates might not have got much of a mention (we are talking about the era when Brachiosaurus was supposedly weighing in at 80 tonnes- roughly double the modern estimate), Alamosaurus was still the biggest dinosaur in the USA at the time. And yet faced with all the crazy horned, crested, spiky chaps it still doesn't get much of a look in.

But with a bit of luck this might change, and poor ignored Alamosaurus might get back into the kids books. Denver Fowler and Robert Sullivan would like to introduce you to SMP VP-1625, SMP VP-1850, and SMP-2104. A portion of the femur, a neck vertebra and a tail vertebra respectively. They're big. Really big. Argentinosaurus-sized big.

So all those fantasies about T. rex versus the uber-sauropod just became scientifically viable. Woohoo!

Lehman, T.M. & Coulson, A.B. 2002. A juvenile specimen of the sauropod Alamosaurus sanjuanensis from the Upper Cretaceous of Big Bend National Park, Texas. Journal of Paleontology 76(1): 156-172.

D’Emic, M., Wilson, J., & Thompson, R. (2010). The end of the sauropod dinosaur hiatus in North America Palaeogeography, Palaeoclimatology, Palaeoecology, 297 (2), 486-490 DOI: 10.1016/j.palaeo.2010.08.032

Denver W. Fowler and Robert M. Sullivan (2011) The first giant titanosaurian sauropod from the Upper Cretaceous of North America. Acta Palaeontologica Polonica in press available, online 07 Feb 2011 DOI:10.4202/app.2010.0105


davegodfrey: South Park Me. (Default)
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