January 5th, 2013 by James Ayre
New research is strongly supporting the theory that many species of dinosaurs used their feathers for sexual display, in a similar way to what modern peacocks do.
The new evidence comes from an analysis done on fossilized dinosaur tail bones by researchers from the University of Alberta.
“U of A Paleontology researcher Scott Persons followed a chain of fossil evidence that started with a peculiar fusing together of vertebrae at the tip of the tail of four different species of dinosaurs, some separated in time and evolution by 45 million years.”
As he notes, the last vertebrae in the tails of the group of dinosaurs known as oviraptors “were fused together forming a ridged, blade-like structure.”
“The structure is called a pygostyle” says Persons. “Among modern animals only birds have them.”
“Researchers say fossils of Similicaudiptery, an early oviraptor, reveals feathers radiating from the fused bones at the tail tip. Similicaudiptery was not known to be a flying dinosaur and Persons contends its tail feathers evolved as a means of waving its feathered tail fans.”
Sp far, there hasn’t been any direct fossil evidence of feathers in the species that followed Similicaudiptery, but there is a lot of other, strong evidence, that they possessed a feathered tail.
“Persons reasons that because the later oviraptor had the same tail structure as the feathered Similicaudipteryx, the tails of later oviraptors’ still served the same purpose, waving feathered tail fans.”
This hypothesis is strongly supported by the structure of the bones and muscles of their tail.
“Individual vertebrae at the base of an oviraptor’s tail were short and numerous, indicating great flexibility. Based on dissections of modern reptile and bird tails, Persons reconstruction of the dinosaur’s tail muscles revealed oviraptors had what it took to really shake their tail feathers.”
“Large muscles extended far down the tail and had a sufficient number of broad connection points to the vertebrae to propel oviraptor’s tail feathers vigorously from side to side and up and down.”
The image that you may have of dinosaurs in your mind isn’t exactly what oviraptors were. These bipedal dinosaurs had diverged considerably “from the iconic, meat eating dinosaur family. Oviraptors were plant eaters that roamed parts of China, Mongolia, and Alberta during the Cretaceous period, the final age of the dinosaur.”
“By this time a variety of dinosaurs used feathers for flight and insulation from the cold, “said Persons. “This shows that by the Late Cretaceous dinosaurs were doing everything with feathers that modern birds do now,” said Persons.
“In addition to feathered-tail waving, oviraptors also had prominent bone crests on their head, which Persons says the dinosaur also may have used in mating displays.”
“Between the crested head and feathered-tail shaking, oviraptors had a propensity for visual exhibitionism,” said Persons.
Here is some more information on oviraptors from Wikipedia:
“Oviraptor is a genus of small Mongolian theropod dinosaur, first discovered by the paleontologist Roy Chapman Andrews, and first described by Henry Fairfield Osborn, in 1924. Its name is Latin for ‘egg thief’, referring to the fact that the first fossil specimen was discovered atop a pile of what were thought to be Protoceratops eggs, and the specific name philoceratops means ‘lover of ceratopsians’, also given as a result of this find. In his 1924 paper, Osborn explained that the name was given due to the close proximity of the skull of Oviraptor to the nest (it was separated from the eggs by only four inches of sand). However, Osborn also suggested that the name Oviraptor ‘may entirely mislead us as to its feeding habits and belie its character’. In the 1990s, the discovery of nesting oviraptorids like Citipati proved that Osborn was correct in his caution regarding the name. These finds showed that the eggs in question probably belonged to Oviraptor itself, and that the specimen was actually brooding its eggs.”
“Oviraptor lived in the late Cretaceous period, during the late Campanian stage about 75 million years ago; only one definitive specimen is known (with associated eggs), from the Djadokhta Formation of Mongolia, though a possible second specimen (also with eggs) comes from the northeast region of Inner Mongolia, China, in an area called Bayan Mandahu.”
Source: University of Alberta
Image Credits: Sydney Mohr; Peacock via Wikimedia Commons
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