Never Found Before: A shark-like fossil with ‘manta wings’

Although there are no teeth in the Aquilolamna have been found, Vullo and his colleagues claim that the fossil belongs to the shark family which also includes white sharks, mackerel sharks and basking sharks. However, its broad head and long, wing-shaped fins indicate that it was not a predatory fish. The Aquilolamna probably used filter foods: he opened his mouth and filtered plankton and other small organisms from the water.

A prehistoric curiosity

Aquilolamna seems to combine the characteristics of a shark with those of a manta. This last species will not evolve until millions of years later. The primitive fish have a long tubular body, just like the sharks that swim in the oceans today. However, its long pectoral fins are reminiscent of those of mantas or evil rays; they form a kind of large underwater wings.

Who would be Aquilolamna being one of the oldest species to move by “submarine flight”, that is, by slowly flapping its fins, as modern mantas do. “It is also possible that Aquilolamna swam relatively slowly, making only small movements with its tail fin. The pectoral fins would have served mainly as stabilizers, ”explains Vullo.

Kenshu Shimada, professor of paleobiology at DePaul University in Chicago, says this physique is very surprising for a shark. The older shark species, the pre-dinosaurs, had a wide variety of body shapes. However, it was believed that at the dawn of the Cretaceous, they were evolving towards their current construction.

Aquilolamna could be proof that a wide variety of odd-looking sharks have been around for much longer than previously thought. “The assumptions made by the researchers about the animal’s physique and its habit of filtering food out of the water are quite convincing,” Shimada said.

Shark or completely different animal?

But not all experts agree that this new animal is a manta-like shark. “The author describes many exceptional characteristics and I have doubts about some of their interpretations. I would therefore be delighted to continue researching this remarkable new fossil. says paleontologist Allison Bronson of Humboldt State University in California.

Although the article mentions skin marks Aquilolamna, outside experts may not see enough detail in the images to determine whether the tissue is in fact fossilized skin or a skin-like material like bacterial mat. And while it is likely that this fish has filtered plankton or other small creatures out of the water, it may also have small, pointy teeth, just like modern filter sharks like the basking shark and the giant beaked shark. . These teeth could determine what other shark species this species is evolutionarily related to, but no teeth were found in the new fossil.

“It’s a shame that no teeth from this specimen have been preserved. This would have allowed researchers to discover the precise taxonomic relationship of this new shark, ”explains Shimada.

The suspicion that this animal was a shark that filtered its food from the water most likely needs to be confirmed with the help of future findings and further analysis. If it was true then it was Aquilolamna long before its modern parents evolved in search of plankton in the sea. It is then possible that this shark is an example of a particular way of filtering food out of water, which occurred before extinction. mass at the end of the Cretaceous period, during which about 75% of all species in the sea became extinct. Other animals that use filter foods, such as the ancestors of the giant beaked shark, whale shark, and basking shark, did not emerge until after Earth’s oceans were reclaimed.

When Aquilolamna was indeed a strange relative of the basking shark, there were probably also alien sharks or sea creatures, not yet discovered by paleontologists. “We have shark and ray fossils from all eras,” says Vullo, “but not much is yet known about the physique of all kinds of extinct species.” Some teeth already found by paleontologists may have belonged to animals with their bizarre appearance.

Even the famous basking shark Otodus megalodon has so far only been described on the basis of its teeth and vertebrae – megalodon means ‘big tooth’ in Greek – so there are different interpretations of how the animal looks. Special fossils, such as those of Aquilolamna, indicate that many fossil sharks may have been stranger than scientists ever suspected.

“If we have the chance to unearth complete skeletons, we might have some big surprises,” says Vullo.

This article originally appeared in English on NationalGeographic.com