Toronto: Some feathered dinosaurs used tail plumage to attract mates, much like modern-day peacocks and turkeys, according to a new study.
A University of Alberta 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.
Persons said the final vertebrae in the tails of a group of dinosaurs called oviraptors were fused together forming a ridged, blade-like structure.
"The structure is called a pygostyle. Among modern animals only birds have them," Persons said.
Oviraptors were two-legged dinosaurs that had already gone through major diversifications 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.
Researchers said fossils of Similicaudipteryx, an early oviraptor, revealed feathers radiating from the fused bones at the tail tip. Similicaudipteryx was not known to be a flying dinosaur and Persons contends its tail feathers evolved as a means of waving its feathered tail fans.
No direct fossil evidence of feathers has been found with the fossils of the oviraptors that followed Similicaudipteryx, but Persons said there is still strong evidence they had a feathered tail.
Since 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, Persons said.
Persons said the hypothesis of oviraptor tail waving is supported by both the bone and muscle structure of the 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 found that 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.
"By this time a variety of dinosaurs used feathers for flight and insulation from the cold.
This shows that by the Late Cretaceous dinosaurs were doing everything with feathers that modern birds do now," Persons said in a statement.
In addition to feathered-tail waving, oviraptors also had prominent bone crests on their head, which Persons said 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.