Paleontologists have announced the discovery of an extraordinary fossil shark in Mexico. They describe Aquilolamna milarcae, A Late Chalk Shark it was wider than it was long, with a strange slender pectoral fins. This shark, far from a savage bite, may have survived by eating plankton.
The team’s research was published today in Science. The authors believe A. milarcae was a lamniform, the same order that today includes the great white and megamouth shark. But the Chalk Shark looked completely different, with its wide mouth, flat head and 6 feet wing span reminiscent of rays. Although rays is also elasmobranches, the group cartilaginous fish containing sharks and skates, A. milarcae precede the appearance of his lookalikes, manta and devil rays, about 30 million years.
‘Aquilolamna is a shark; there is definitely no problem, ”Romain Vullo, a paleontologist at the University of Rennes in France and lead author of the article, said in a video call. ‘This generation of sharks became extinct at the end of the Cretaceous without descendantsnts. Thereafter, the ecological niche became vacant, and thereafter a generation of batoid – rays—develops to manta rays. ”
Vullo described the shark as a limp predator, which, like all other sharks, would have used it tail fin to propel itself through the shallow sea that once occupied central North America. (This is another difference of rays, which wave their wing-like fins to get from A to B.) After driving himself, A. milarcae would have used the remarkable pectoral fins to do the marine equivalent of hang gliding, sailing through the sea and perhaps devouring the plankton that got in the way.
G / O Media can get a commission
“It is indeed an exciting discovery,” Kenshu Shimada, a professor of paleobiology at DePaul University in Chicago and an expert on ancient shark species, said in an email. “The exact taxonomic identity of this new shark is still in doubt, but its body design, especially its extraordinarily elongated paired pectoral fins, is not only unique within the shark order Lamniformes, but also throughout the shark world.”
It’s not sure that the shark was planned, but that’s the hypothesis of Vullo and his team, based on the fact that the fossil had no teeth. This is surprising because most old sharks are identified exclusively by their teeth because it holds better as the cartilage skin and skeleton. The team poses the possibility that A. milarcae is either a relative of or the same animal as Cretomanta, another elasmobranch that is so far only identified by his teeth.
“When you work on a single sample, even if it is very well preserved, you always miss information, and here is the most important information we miss, the teeth,” Vullo said. This is what I want to answer: What was the denture of? Aquilolamna, and see if it is indeed Cretomanta. ”
This is a chalk approach Guess who?, instead of eliminating candidates for the fossil sharks, more is coming to the surface. While this will be a bias for those who play the game, it is a boon for paleontologists, who are increasingly learning about the biodiversity of the prehistoric sea of the earth.