Ornithomimus (“bird mimic”) is a dinosaur genus belonging to a group commonly known as the “ostrich dinosaurs” or “ostrich mimics”. This name comes from their very ostrich-like appearance, with toothless beaks, long swan-like S-shaped necks, and powerful muscular legs. There are currently two known species of Ornithomimus: O. velox and O. edmontonicus. This genus lived in western North America at the end of the Cretaceous Period, 75-65.5 MYA.
It was most likely omnivorous, and you can tell that by the size of its belly. Plant-eating animals need large guts to process their food, in contrast to carnivorous animals. If you look at specimens of Ornithomimus, or indeed any ornithomimid dinosaur, particularly ones which preserve the gastralia (belly ribs), you will see that they outline the stomach area. In contrast to the somewhat starved bodies portrayed by many paleo-artists following in Gregory Paul’s footsteps, they clearly show a wide belly. Look here to see an example: http://en.wikipedia.org/wiki/File:Ornithomimus_edmontonicus.jpg
People had suspected for a while that Ornithomimus and its kind had feathers. There were two reasons for this. Firstly, there was its obvious bird-like appearance. Anything which looked THAT bird-like just HAD to have feathers! Well, it’s an interesting point in terms of comparative anatomy, but there was really no hard evience to support it, and no real credible analysis of various dinosaur types and their relations to birds which suggested that ornithomimids had feathers. The second reason answered that last point. With advances in phylogeny (determining where different species fit into the scheme of life and how they are related to each other), paleontologists have determined that the ornithomimids belong to a large group of very bird-like dinosaurs called the maniraptorans. This group included the ornithomimids, therizinosaurs, oviraptors, and the “real” raptors – the Jurassic Park-style raptors, specifically the dromaeosaurids and the troodontids. Maniraptorans are the closest ancestors of birds, and many of them are known to have been feathered. This would imply that the ornithomids were feathered as well. This argument was a bit more convincing than the “it looks like a bird so it must have feathers” argument which was around during the 80s and 90s. However, although it made a good point, there was still no physical evidence to back it up. If ornithomimids were feathered, why hadn’t any feather fossils been found in association with their skeletons?
In the early 2000s, that changed. When three specimens were examined more closely, scientists discovered that two of them possessed “quill knobs” (the places where feathers attach onto the bones) on the arms, and a third specimen – a juvenile – actually had feather impressions along its neck, back, and legs. In 2012, a report was published in the academic journal Science demonstrating that at least one ornithomimid species, Ornithomimus edmontonicus, was covered in feathers throughout its life, and that the adults actually had modern pennaceous feathers on their arms forming flightless wings. Click here to see a preview of this article: http://www.sciencemag.org/content/338/6106/510.
This is a drawing of Ornithomimus based upon the findings in that report. As you can see, the arms sport fully-developed albeit flightless feathered wings. Also take note that the feathers do not cover the whole body all around, but only the top and sides – the underside is bare. The color is my own aesthetic guesswork. I decided to make the throat bright red, which (I like to imagine) was used as a courtship display similar to modern reptiles and birds.
Take care, everyone.
Categories: Paleontology, Uncategorized
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