London: Male pterodactyls, a class of flying reptiles which lived alongside dinosaurs between 220 and 65 million years ago, used their giant head crests to woo the opposite sex, a rare fossil find has revealed.
Scientists who have unearthed a 160-million-year-old fossil, dubbed "Mrs T", believe that while female pterodactyls had no decorative markings on their heads, the males sported impressive plumes of feathers, five times the size of their skull, which they used to show off to prospective mates.
It had previously proved impossible to say whether the remains of the reptiles, also called pterosaurs, were male or female, and "sexing" them has foxed experts for more than 100 years.
The evidence comes from Mrs T, the nickname given to a female reptile preserved together with the egg she was about to lay.
The creature, whose skeletal remains were uncovered from Liaoning Province in north-east China, belonged to the group of darwinopterus pterosaurs. It had relatively large hips to accommodate the passage of eggs and had no head crest, the Daily Mail reported.
Other Darwinopterus specimens, now known to be male, have smaller hips and well-developed crests. Scientists believe these were probably used to ward off rivals or attract mates.
Lead researcher Dr David Unwin, from the University of Leicester, said: "Pterosaurs, flying reptiles, also known as pterodactyls, dominated the skies in the Mesozoic Era, the age of dinosaurs, 220 to 65 million years ago.
Many pterosaurs have head crests. In the most spectacular cases these can reach five times the height of the skull. 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. The fossil we have discovered, an individual of
Darwinopterus, is preserved together with an egg showing that it must be female. 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."
Dr Unwin's team, who described the find in the journal Science, also said that future pterosaur fossil finds in which the skull or hips are preserved can help scientists to 'sex' the creatures.
Dr Unwin added: "Gender is one of the most fundamental of biological attributes, but extremely difficult to pinpoint with any certainty in the fossil record.
"Being able to sex pterosaurs is a major step forward.Finally, we have a good explanation for pterosaur head crests, a problem that has puzzled scientists for more than 100 years. Mrs T is thought to have been killed in a tragic accident, perhaps a storm or one of the volcanic eruptions.