Paleontologists have announced the discovery of an extraordinary fossil shark in MexicoThey describe Aquilolamna milarcae, a Late Cretaceous shark that was wider than long, with a strange look slender pair of pectoral fins. This shark, far from a ferocious biter, survived by eating plankton.
The team’s investigation 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 Cretaceous Shark looked completely different, with the wide mouth, flat head and six feet wingspan reminiscent of rays. Although rays are also elasmobranches, the group of cartilaginous fish that also contain sharks and skates, A. milarcae precedes the appearance of his lookalikis, manta and devil rays, by about 30 million years.
Aquilolamna is a shark; absolutely no problem, ”said Romain Vullo, palaeontologist at the University of Rennes in France and lead author of the paper, in a video interview. “This line of sharks became extinct at the end of the Cretaceous Period without descendantsnts. Then the ecological niche was released, and then a genus of batoids – rays – becameevolved into manta rays. “
Vullo described the shark as a languid predator that, like all other sharks, would have used caudal fin to propel itself through the shallow sea that once occupied central North America. (That’s another difference from rays, which wave their wing-like fins to get from A to B. Moved after itself, A. milarcae would have used those remarkable pectoral fins to do the marine equivalent of hang gliding, sail the seas and maybe gobble up plankton that got in the way.
G / O Media can receive a commission
“This is an exciting discovery indeed,” 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 questionable, but its body design, especially the exceptionally elongated paired pectoral fins, is unique not only within the Lamniformes shark order, but also throughout the shark world.”
It is not certain that the shark was planktivore, but that’s the hypothesis of Vullo and his team, based on the fact that the fossil had no teeth. This is surprising, as most ancient sharks are identified only by their teeth, as they are better preserved than the cartilaginous skin and skeletonThe team suggests 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 specimen, you always miss some information, even though it is very well preserved, and here the most important information we miss is the teeth,” Vullo said. “This is what I would like to answer: what were the teeth Aquilolamna, and verify that it is indeed Cretomanta
It’s a chalky version Guess who?, where instead of eliminating candidates for the fossil sharks, more are surfacing. While that would be a bane to anyone playing the game, it is a boon to paleontologists, who are learning more and more about the biodiversity of Earth’s prehistoric seas.