160mn-yr-old pterodactyl fossil solves dino sex riddle

WASHINGTON - Scientists from the Universities of Leicester, Lincoln and the Geological Institute, Beijing, have finally solved the mystery of sex between pterodactyls - flying reptiles that lived alongside dinosaurs between 220-65 million years ago.

Fossils discovered together with an egg in Jurassic rocks (about 160 million years old) in China show that females were crestless, solving the long-standing problem of what some pterosaurs did with their spectacular head crests: showy displays by males.

“Scientists have long suspected that these crests were used for some kind of display or signalling and may have been confined to males, while females were crestless. But, in the absence of any direct evidence for gender this idea remained speculative and crested and crestless forms were often separated into completely different species,” said David Unwin.

“This type of discovery, in which gender can be determined with certainty, is extremely rare in the fossil record, and the first to be reported for pterosaurs.”

The newly discovered fossil has been named ‘Mrs T’.

“Mrs T shows two features that distinguish her from male individuals of Darwinopterus. She has relatively large hips, to accommodate the passage of eggs, but no head crest. Males, on the other hand, have relatively small hips and a well developed head crest. Presumably they used this crest to intimidate rivals, or to attract mates such as Mrs T,” said Unwin.

“Mrs T shows two features that distinguish her from male individuals of Darwinopterus. She has relatively large hips, to accommodate the passage of eggs, but no head crest. Males, on the other hand, have relatively small hips and a well developed head crest. Presumably they used this crest to intimidate rivals, or to attract mates such as Mrs T.”

He added, “Now, we can exploit our knowledge of pterosaur gender to research entirely new areas such as population structure and behaviour. We can also play matchmaker for pterosaurs bringing back together long separated males and females in the single species to which they both belong”.

The fossil not only indicates the gender but also tells us about pterosaur reproduction, Unwin said.

“Mrs T’s egg is relatively small and had a soft shell. This is typical of reptiles, but completely different from birds which lay relatively large hard-shelled eggs.

“This discovery is not surprising though, because a small egg would require less investment in terms of materials and energy - a distinct evolutionary advantage for active energetic fliers such as pterosaurs and perhaps an important factor in the evolution of gigantic species such as the 10 meter wingspan Quetzalcoatlus.”

Details of the unique new find are published today (January 21) in the journal Science. (ANI)