Sunday, November 4, 2018

Harpymimus: Beast of the Week

This week we will be checking out a bird-like dinosaur that was named after a fearsome mythical creature.  Let's check out Harpymimus okladnikovi!

Harpymimus was a theropod dinosaur that lived in what is now Mongolia, during the early Cretaceous period, between 107 and 100 million years ago.  It measured a little over six feet long from snout to tail and would have almost certainly been covered in feathers when alive.  The genus name, Harpymimus, translates to "harpy mimic" in reference to the harpy, a monster from Greek mythology with the head of a human and body of a bird.  I'm not sure why this dinosaur, in particular was named after a harpy other than the fact that it was bird-like, which isn't really a unique feature among dinosaurs.

Harpymimus life reconstruction in watercolors by Christopher DiPiazza.

Harpymimus was a very early member of the group of theropod dinosaurs, called the ornithomimosaurs.  These dinosaurs are known for having had long legs, long, slender necks, and relatively small heads with beaks.  The late Cretaceous-living Gallimimus and Struthiomimus are more famous members of this group, and Deinocheirus was a very large member.  Since Harpymimus lived so much earlier than most of the other known ornithomimosaurs, it also showcases a number of features in its anatomy that would change as its descendants became more specialized.  This is a great example about how studying fossils allows you to see how the evolution of many kinds of organisms changed over millions of years, which also tells us a lot about organisms that are still alive with us today!

Harpymimus skeleton on display at the Mongolian Academy of Sciences)

Harpymimus had relatively large eye sockets, suggesting it could see well, and had a long, slightly down-turned snout.  It had teeth on the very tip of its lower jaw.  Teeth in general are considered an ancestral trait for this kind of dinosaur, since all the late Cretaceous ornithomimosaurs were completely toothless.  Harpymimus teeth were tiny and cylinder-shaped.  They would have been hardly noticeable unless you were to look directly into Harpymimus' mouth up close.  What these teeth were exactly for is a mystery.  Many hypothesize that Harpymimus could have been an omnivore, eating plant material as well as hunting for small prey, like invertebrates or other kinds of small animals it could snap up.

Harpyimimus had long arms tipped with three fingers on each hand, but the first digit was significantly shorter than the other two.  This is typical for most kinds of three-fingered theropods, but would eventually change in later-living ornithomimosaurs, which had three fingers of equal lengths on each hand.

Harpymimus had long, powerful legs, which would have enabled it to have run quickly.  While later ornihomimosaurs only had three toes on each foot, Harpymimus possessed a fourth (but digit 1) tiny toe, called a hallux, which was on the inside of each foot.  This is also a trait common to most theropods, but evolved out as ornithomimids became more specialized later in the Cretaceous.

That is all for this week!  As always please comment below or on our facebook page!

References

Barsbold, R. and Perle, A. (1984). [On first new find of a primitive orithomimosaur from the Cretaceous of the MPR]. Paleontologicheskii zhurnal2: 121-123

Kobayashi, Y. and Barsbold, R. (2005). "Anatomy of Harpymimus okladnikovi Barsbold and Perle 1984 (Dinosauria; Theropoda) of Mongolia." In Carpenter, K. (ed.) The Carnivorous Dinosaurs. Indiana University Press: 97-126

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