The Evolution of Feathered Dinosaurs

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History of Life on Earth

Prof. Ross

November 19, 2015

Birds of a Feather Evolve Together: The History of Feathered Dinosaurs

In 2005, in South Dakota’s famous Hell Creek Formation, a fascinating new species of raptor was discovered. Known as the “Dakotaraptor” by paleontology enthusiasts, this fearsome dinosaur had a 9.5 inch ‘sickle claw’ which sliced prey to bits (Brait 2015). This claw was made for piercing flesh, not crushing bones like the bulky claws on a T-Rex, which is evident from its laterally compressed shape. Dakotaraptors lived roughly 66 million years ago which is long past the time organic material like feathers can be preserved. However, scientists are convinced that quill-like knobs on the lower arm bones of the Dakotaraptor indicate the presence of feathers (Brait 2015). When we think of feathers it is natural to also think of flight, but the Dakotaraptor was much too heavy. So what was the purpose of these feathers, if they had one at all? Scientists had some hypotheses on this topic which include: Protecting eggs, capturing prey, and attracting mates (Brait 2015). By looking at the several paleontological discoveries of non-avian feathered dinosaurs made in the past 20 years, we can gain more clarity on the varying types, origins, and uses of dinosaur feathers.

The scientists’ hypotheses about the Dakotaraptor show us how many different uses there are for dinosaur feathers. A scientific article from the University of Kansas Paleontological Institute looked further into the topic of dinosaur feather uses. Quill-like knobs like the ones found on the Dakotaraptor are present on modern birds as well. They act as ligament attachment sites for fibers, providing extra support needed during flight (DePalma et al 2015). Other ancient species like the Rahonavis and the Velociraptor also had quill-like knobs similar to the ones found on the Dakotaraptor (DePalma et al 2015). The smaller Dromaeosaurids, which could fly, had flight feathers...