Preserved Skin and Feathers Link Ornithomimus Dinosaurs to Birds

Summary: Preserved skin and feathers link Ornithomimus bird-like dinosaurs to modern-day birds, according to a study in Cretaceous Research Oct. 28, 2015.

"This is an illustration of Ornithomimus based on the findings of preserved tail feathers and soft tissue"; credit Julius Csotonyi: Usage restrictions -- "Please ensure caption and credit info appear," via EurekAlert!

A study in the Oct. 28, 2015, edition of Cretaceous Research announces the discovery by a University of Alberta paleontology undergraduate of an Ornithomimus edmontonicus fossil with preserved feathers and skin.

The specimen becomes the third adult fossil from Alberta, Canada, to link bird-like dinosaurs to modern-day birds.

Wispy feathers cover the specimen’s back, chest, neck and tail even though they lack bird-like barbs or hooks to keep the plumage sufficiently air-resistant and stiff for flight. Both leg bones display fossilized soft tissue from the mid-thigh down to both clawed, three-toed feet.

Ornithomimus edmontonicus ("Edmontonian bird mimic") emerges as a beaked, big-brained, burly-legged, long-necked, long-tailed, small-headed, toothless, 2-meter- (6.56-foot-) tall omnivore that looks like a flightless, present-day bird.

As the fossil’s technician, the publication’s first author and a student with 10 years’ experience preparing museum fossils in Canada and the United States, Aaron J. van der Reest finds the 75-million-year-old specimen indicative of shared ancestry with modern-day birds and prehistoric dromaeosaurids (feathered running lizards).

Featherless soft tissue and long tail feathers give indications of convergent evolution with emus and ostriches.

Mr. van der Reest holds that “Ostriches use bare skin to thermoregulate. Because the plumage on this specimen is virtually identical to that of an ostrich, we can infer that Ornithomimus was likely doing the same thing, using feathered regions on their body to maintain body temperature. It would’ve looked a lot like an ostrich.”

Fluffiness is predicted from ornithomimid membership in the Coelurosauria (feathered hollow-tailed lizard) clade of alvarezsaurs, compsognathids, deinonychosaurs, ornithomimosaurs, oviraptorosaurs and tyrannosaurs.

The specimen that the study calls UALVP 52531 joins previous discoveries -- an adult with shafted feather-marked forearms, a juvenile with filamentous feathers and an adult with fuzzy feathers -- to confirm fuzziness in juvenile and mature ornithomimids and complex arm-feathers in adults.

As co-investigator of the discoveries from 1995, 2008 and 2009, Darla Zelenitsky of the University of Calgary’s department of geoscience knows of bird-like feathers and proto-wing forearms facilitating brooding, resting, and strutting functions: “We infer that because these wing feathers are not showing up until later in life, they were used for reproductive purposes.”

Mr. van der Reest’s two-year-long preparations of UALVP 52531, encased in rock since 2009 and missing forelimbs and head, lead to Royal Ontario Museum vertebrate paleontology curator David Evans’s pronouncement: “It is the most complete feathered dinosaur specimen found in North America to date.”

Alexander P. Wolfe, co-author and paleobiologist, mentions the “many components of the morphology of this fossil as well as the [electron microscopy-scanned, three-dimensional keratin] chemistry of the feathers that are essentially indistinguishable from modern birds.”

Mr. van der Reest notes regarding co-authorship with world-famous paleontologist Philip J. Currie and respecting UALVP 52531’s abdomen-to-thigh skin-webs predicting bird abdomen-to-knee skin-bridges: “This is my baby. I get to go as far as I can with it.”

UALVP 52531: UAlbertaScience @ualbertaScience, via Twitter Oct. 28, 2015

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

This is an illustration of Ornithomimus based on the findings of preserved tail feathers and soft tissue"; credit Julius Csotonyi: Usage restrictions -- "Please ensure caption and credit info appear," via EurekAlert! @ https://www.eurekalert.org/multimedia/746313; (EurekAlert! news release @ https://www.eurekalert.org/news-releases/860943); (former URL @ http://www.eurekalert.org/multimedia/pub/102142.php)

UALVP 52531: UAlbertaScience @ualbertaScience, via Twitter Oct. 28, 2015, @ https://twitter.com/ualbertaScience/status/659503726806343680

For further information:

111222sanya. 26 October 2012. "First feathered dinosaur Ornithomimus edmontonicus." YouTube.
Available @ https://www.youtube.com/watch?v=j9DI1y4iZeg

Mostly Mammoths @MostlyMammoths. 29 October 2015. "Wow!! @UAlberta Aaron van der Reest finds fossil feathers, skin on ostrich-like dinosaur." Twitter.
Available @ https://twitter.com/MostlyMammoths/status/659765362343469056

Pascoe, Jennifer. 28 October 2015. "Prehistoric plumage patterns." University of Alberta Faculty of Science > News.
Available @ https://uofa.ualberta.ca/science/science-news/2015/october/prehistoric-plumage-patterns

UAlbertaScience @ualbertaScience. 28 October 2015. "Undergrad discovers plumage patterns, tightens link btw dinos and birds." Twitter.
Available @ https://twitter.com/ualbertaScience/status/659503726806343680

van der Reest, Aaron J., et al. March 2016. "A densely feathered ornithomimid (Dinosauria: Theropoda) from the Upper Cretaceous Dinosaur Park Formation, Alberta, Canada." Cretaceous Research, vol. 58 (March 2016): 108-117. DOI: 10.1016/j.cretres.2015.10.004
Available @ http://www.sciencedirect.com/science/article/pii/S0195667115300847

Zelenitsky, Darla K., et al. 26 October 2012. "Feathered Non-Avian Dinosaurs from North America Provide Insights into Wing Origins." Science, vol. 338, no. 6106: 510-514.
Available @ https://www.sciencemag.org/content/338/6106/510