After studying a curious feature in the tail section of oviraptor fossils, a paleontologist from the University of Alberta has concluded that these small dinosaurs must have used their tail plumage to attract mates, a strong indication that these creatures were more sophisticated, elegant — and daintier than previously thought. The theory also adds further credence to the suggestion that feathers played an important intermediary function in the lives of dinosaurs prior to providing them with the capacity for flight.
To reach this conclusion, researcher Scott Persons studied the vertebrae section in the tails of four different dinosaur species, including oviraptors. He discovered that the bones were fused together to form a blade-like structure called a "pygostyle" — a feature exclusive to birds.
Consequently, the fossils of Similicaudipteryx (an early oviraptor) indicate that a fan-like structure likely emanated from the pygostyle. And because Similicaudipteryx could not fly, its tail feathers were likely an ornamental display that it used to attract prospective mates.
Persons speculates that, because the oviraptors who came later also featured a similar tail structure, they likely used their tail plumage for the same purpose.
Moreover, Persons argues that the feathers weren't just a static display, and that they were shaken by the dinosaurs. He points to the fossil evidence as proof. Similicaudipteryx's tail-tip vertebrae were short and numerous — indicating considerable flexibility. And when compared to modern reptile and bird tails, the dinosaur's tail muscles had the attributes necessary for vigorous tail shaking — including large muscles that extended far down the tail.
"You stick a feather fan on the end of a highly dextrous and muscular tail and you've got what I think is a tail built for flaunting, that could shake a tail feather side to side, raise it up, strike a pose," Persons told the CBC.
And in fact, Persons argues that the shaking could have been to an extent greater than what's seen in modern-day peakcocks and turkeys.
The study appears in the journal Acta Palaeontologica Polonica.
Image: Sydney Mohr.