#ornithomimosaurs

[femboy-fever]

Saw my first albino dino (a Gallimimus), but I decided I'd be collecting the albinos and melanistics on separate save files, so I had to skip him. :(

Someday, my beautiful white chicken. Someday...

[a-dinosaur-a-day]

Randomly though of how if ornithomimids were still around, they'd probably be classified as ratites until genetic analysis became possible.

Oh yeah, I wonder about that alternate universe all the time ngl

[ask-palaeoblr]

What do we know about the diet of Ornithomimus, Gallimimus and Struthiomimus?

[dinosaur-discourse]

Why would a T-Rex or a velociraptor have tiny wings as shown in the picture you linked? Obviously they aren't for flying. Did they both descend from flighted species?

That is actually a theory that some paleontologists have put forth.  The most primitive known dromaeosaur, Microraptor, was capable of gliding, or possibly even powered flight; some paleontologists believe that dromaeosaurs were descended from flying animals, but became secondarily flightless in order to hunt larger prey on the ground.

However, there are other theories as to why these dinosaurs would have had wing-like arm feathers.

They were used to assist in incubating eggs and shielding the young from the elements.

They were used as display structures to attract mates or frighten away predators.

They were used for balance while restraining prey.

They were used for wing-assisted incline running.

They were vestigial in adulthood, but babies and juveniles used them to glide or fly and escape from predators.

I personally think that many of these explanations are plausible, but I don’t necessarily believe the “flying common ancestor” theory.

The only dinosaurs known to have possessed long, wing-like feathers on their arms are dromaeosaurs, ornithominosaurs, and oviraptorosaurs.  All three of these dinosaur types are coelurosaurian theropods, with the dromaeoaurs and oviraptorosaurs belonging more specifically to the subgroup Maniraptora, along with therizinosaurs, scansoriopterygians, and troodontids.  These other maniraptorans show no evidence of wing-like feather arangements, which seems strange, given that if dromaeosaurs evolved from flying ancestors, their closest relatives would have had to as well.

I think that wing-like feather arrangements evolved in ground-dwelling theropods first, perhaps for some of the purposes listed above, such as the protection of young or mating display.  I also think that they evolved separately numerous times among different theropod groups, and only led to flight in the dromaeosaurs.

[dinosaur-discourse]

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.

[a-dinosaur-a-day]

House Raptor: "Gotta Go Fast"

But they weren’t that fast actually 

That’s better for an Alvarezsaur, or Ornithomimosaur