September 15, 2014
Ancient Flying Reptile Resembled Ikran From Avatar Movie
John Hopton for redOrbit.com - Your Universe Online
Fossils discovered in China are providing clues to a species of flying reptile that may have had a jaw pouch for catching and storing food. The pterosaurs lived around 120 million years ago and scientists working on the project noted that as well as being similar to pelicans, they resembled the fictional winged creature Ikran from the movie Avatar. So much so they named it Ikrandraco avatar.Pterosaurs, which are more closely related to modern birds than any currently existing reptile, often had crests on their skulls. However, the newly discovered species is the first known to have had a crest on its lower jaw and none on the skull. The study, published in the journal Scientific Reports, proposes that a hooked ending on the chin crest was for an attachment, possibly a pelican-like throat pouch. The theory is that the pterosaurs skimmed water surfaces while in flight and scooped up prey. “Ikrandraco avatar could have foraged by flying low over the water and, upon visually locating a prey item near the surface, could have lowered the jaw partially immersing it,” said the report.
Two almost entirely complete fossils, representing a find of unusual extensiveness, show that Ikrandraco was around 75 centimeters long and had a wing span of 1.5 meters. The creatures had at least 40 pairs of small teeth and the crest on the lower jaw was about 13 centimeters long. Senior author Alexander Kellner of Brazil's Federal University of Rio de Janeiro told National Geographic's Dan Vergano that a crest of this size is larger than that of any other flying reptile.
Despite the close resemblance to pelicans, the throat pouch feature is evolutionarily distinct. Pelicans are descended from dinosaurs, not pterosaurs, and should the theory of throat pouches and skimming flight in Ikrandraco be proved correct, the separate evolution of similar useful features would be assumed.
Study lead author Xiaolin Wang of the Chinese Academy of Sciences in Beijing says that the pterosaurs likely evolved throat pouches when presented with plentiful fish near the surface of the water, just as the ancestors of pelicans had done.
The separate evolution of comparable characteristics in different species, sometimes millions of years apart, is known as convergent evolution. Because environments continue to have similar features, equivalent physical attributes in different creatures continue to be advantageous.
Some pterosaur experts not connected to the study are skeptical about the skimming to feed theory. Paleontologist Richard Butler of the University of Birmingham, UK, told Vergano that "These are spectacular new fossil specimens," but points to a 2007 PLOS Biology analysis which concluded that it was probably impossible that pterosaurs fed by skimming. Equally, Mark Witton of the University of Portsmouth, UK, says that, "The proposed feeding strategy sounds unlikely and bizarre to me," adding that, "Modern animals show us that flying relatively low over the water to catch prey is a successful ecological strategy, but they do this without any bizarre crest trawling.”
Kellner admits that the skimming hypothesis is "controversial," but says that that an upcoming reanalysis of pterosaur flight dynamics by his team will show that the ancient reptiles were more capable of skimming than the 2007 study indicates. "Regarding Ikrandraco, it would be a 'limited' skimmer," Kellner said. "But this is the best explanation for such a deep crest limited to the lower jaw."
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