Friday, May 25, 2012

The Anatomy of Troodontids

As you can obviously tell, from the name of my blog, troodontids are among my absolute favourite dinosaurs. Therefore, it should come as no wonder that I am very interested in them. One of the most fascinating topics surrounding troodontids, in my opinion, is their very unique anatomical structure, and what ecological functions it might possibly have served.

Obviously, any theories about an extinct animal's behaviour must start with the creature's anatomy. As for troodontids, they have a very uniquely-specialized body configuration, which, I think, really is very fascinating. For starters, most troodontids had a long, thin snout. Some species, such as Troodon, had many small teeth, with very large serrations, like those of modern-day iguanid lizards. Others, such as Byronosaurus, had teeth with no serrations, at all. However, despite these differences in tooth morphology, overall, troodontids' jaws were mostly similar.

One of the most distinctive characteristics of troodontids is their eyes. Most troodontids had huge eyes. In Troodon, the eyes were 2 inches wide. Although we do not know exactly what purpose such large eyes might have served, I have now come to the conclusion that troodontids were most likely nocturnal, and that those huge eyes probably helped them to hunt for their prey, at night.

Ears are another puzzling aspect of troodontid anatomy. Unlike any other non-avian dinosaurs, troodontids actually had asymmetrical ears; i.e., the left ear was placed higher up, on the head, than the right ear was. While there were no other Mesozoic dinosaurs with this very curious adaptation, there is one group of animals living today that appears to be eerily similar, to troodontids, in this respect. That is the owls. Like troodontids, owls also have asymmetrically-aligned ears, with one ear being higher up on the head, than the other. This is an adaptation that helps owls to listen carefully to small prey, at night. Although we have no way of knowing for sure, without a time-machine, that troodontids might also have used this adaptation for similar purposes certainly cannot be ruled out.

Another distinctive feature of the Troodontidae is the claws on their second toes. Just like the dromaeosaurids, troodontids most likely used their "sickle-claws" to help them kill their prey. I imagine it would be quite useful for disemboweling large prey. Then again, it could also be used to subdue smaller prey.
Like other maniraptorans, troodontids are believed to have possessed feathers. In my opinion, this makes perfect sense, due to their very close relationship to birds. We also have some direct fossil evidence of this, since several fossils of small troodontids have been preserved, with some impressions of feather-like structures, in the rocks that were surrounding them.

All in all, troodontids really are a very fascinating group of dinosaurs, and I will also be blogging more about them, later on.

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