The riddle of sex Mrs. T

One female and one male Darwinopterus. The male (right) has a huge peak
One female and one male Darwinopterus. The male (right) has a huge peak

For the first time, paleontologists are able to distinguish between males and females inthe flying reptiles after discovering a fossilized specimen and its egg

If it is difficult sexing a chicken, how will not be know the sex of a flying reptile of the Mesozoic. Until now, paleontologists had serious doubts about whether the remainsdiscovered in archaeological had belonged to a female or male. There are somewhere to look. But the discovery of an ancient fossil, which has dubbed "Mrs. T" for the first time allow scientists to make distinctions between the sexes in the pterodactyl, thewinged monsters that star in many scenes of Steven Spielberg's movie Jurassic ParkIII. The work is published in the journal Science

A team of researchers from the University of Leicester discovered the fossilized flying reptile with an egg on the rocks 160 million years in the province of Liaoning, in northeast China. This is the first direct evidence of sex in these extinct giants, as the copy which had a wingspan of almost a meter, died when he was about to lay their eggs in a crash that broke his left forearm. Perhaps the death occurred during a storm or a volcanic eruption, common in that part of the country during that time. The remains show that the females had no crest, while males are very colorful and looked spectacular.

An attractive signal

Pterosaurs, also known as pterodactyls ruled the skies in the Mesozoic era of the dinosaurs, from 220 to 65 million years. "Many have a crest on its head. In the most spectacular, they can reach five times the height of the skull, "says David Unwin, paleobiologist at the University of Leicester. "Scientists have long suspected that these peaks were used for some type of display or signaling and that only worn by males, but in the absence of any direct evidence, the idea was just a speculation and animals with and without ridge were often separated into two completely different species. "

"Ms T", a female Darwinopterus, fossilized egg with her
"Ms T", a female Darwinopterus, fossilized egg with her
The new fossil find, the "Mrs. T" (a contraction of "Lady Pterodactyl") is to dispel the doubts. She has no crest and wide hips, possibly to facilitate the passage of eggs, while males can be distinguished by their narrower hips and a "crown" in his head well developed. Possibly, this peak males served to intimidate rivals or to show off and win the females, an issue that has intrigued scientists for over a hundred years.
"Sex is one of the most fundamental biological attributes, but it is extremely difficult to identify with certainty in the fossil record. Being able to sex a pterosaur is a great step forward, "says Unwin. The researcher is willing to "play matchmaker 'to bring males and females of the same species that had been separated by scientists in different species.

Enlarged image of the fossilized egg
Enlarged image of the fossilized egg
Small and soft-shelled

The discovery of pterosaur fossil also sheds light on reproduction. The egg of the "Mrs. T" is relatively small and had a soft shell. This is typical of completely different reptiles and birds, which lay larger eggs and hard shell. Because a small egg requires less material and energy investment, is a clear evolutionary advantage for Pterosaurs and perhaps an important factor in the evolution of species as Quetzalcoatlus giant, ten-meter wingspan.

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