Hey, it's Flora Licksman, and this is Science Friday.

Today in the show, a weird crest on an ancient reptile has scientists scratching their heads.

Paleatology often requires a kind of fantasy functional biology where you go, wow, what were these for?

Brace yourself, new animal appendage just dropped.

Paleontologists have identified an ancient reptile with a towering crest on its back

that is not made of skin or scales or feathers or antler,

but something else entirely that we have never seen before.

The small creature sporting this befuddling back fin is named the Mirasora

and lived during the mid-Triassic period about 250 million years ago,

just before dinosaurs evolved. Here to discuss this novel skin gear and what it tells us about

the evolution of dinosaurs, birds and feathers, is Dr. Richard Prum, Professor of Ecology

and Evolutionary Biology, and head curator of ornithology at the Peabody Museum of Natural History

at Yale University.

He's based in New Haven, Connecticut.

Rick, welcome back to Science Friday.

Thank you. It's a pleasure to be here.

New flesh thing. That seems big.

Yeah. Well, you know, in the skin world, this is a big deal.

These structures are just so weird compared to anything we're familiar with among

extant animals. Well, tell me more. Why are they weird? First of all, these are the structures

we're talking about are part of a group of anatomical parts that are things that grow out of the

skin. These integumentary appendages include hair and feathers and scales,

...