2013 in paleontology

sauropolis-princeps  asked:

Buddy gimme that sweet Deinocheirus discourse

Deinocheirus has a story behind it that’s even weirder than Therizinosaurus’, if you can believe such a thing.

Deinocheirus” means “terrible hands”, and from the image above, you can probably see why.  Like Therizinosaurus, the original specimen - discovered in Mongolia in 1965, consisted solely of a gigantic pair of arms, each one over eight feet in total length.  It was clear that they belonged to a theropod, but again, no one was sure what kind, and no additional fossils were discovered for almost fifty years afterward.

In the meantime, the true nature of Deinocheirus became one of the most maddening mysteries in paleontological history.  Theories abounded: did they belong to some sort of giant carnosaur that used them to tear apart its prey?  Was it a new species of therizinosaur?  Was it specialized for climbing, using its big claws to haul itself up treesl?

Then, in 2013, it was announced that a pair of new specimens had been discovered, and that together, nearly the entire skeleton of Deinocheirus was represented.  Paleontologists were thrilled by this.  People at the 2013 Society of Vertebrate Paleontology Conference applauded at this news.  What would the answer to this fifty-year mystery be, they wondered?  What did Deinocheirus really look like?

Holy shit.

Deinocheirus, it was revealed, was an ornithomimosaur - a giant ornithomimosaur, almost half again as big as the second-biggest known ornithomimosaur.  It had a huge, duck-like beak, and a pair of beady little eyes.  It had a bison-like hump on its back.  What the hell was this thing?  How in God’s name did this ridiculous animal fit into the paleontological scheme of things?

One of the current theories is that Deinocheirus convergently evolved to resemble therizinosaurs - that is, it independently developed many of the same traits that characterized therizinosaurs in order to live a similar lifestyle.  Unlike its smaller relatives, which were traditionally fast runners, Deinocheirus was a big and comparatively sedentary creature that defended itself with its sheer size.  It likely used its claws to shear off plant matter to eat, but unlike any known therizinosaurs, it was likely specialized for eating water plants.  Its broad, duck-like beak would have been quite suited for cropping soft water weeds or hoovering up algae.  In addition, fossilized fish were found in its gut, indicating occasional omnivory.

While the initial mystery of Deinocheirus is solved, the truth of the matter only raises more questions.  It’s exciting to me for much the same reason as Spinosaurus.  We have very few large, amphibious creatures like this alive today; the implication given by these dinosaurs, that entire ecosystems of such animals existed in the past, really sparks the imagination.