Aquilolamna milarcae had a shark-like main body, with ray-like wingsOscar Sanisidro

The whale shark and the manta ray are perhaps two of the ocean’s most fascinating large fishes. Well, scientists have now announced the discovery of a prehistoric ancestor of both, that looked like a cross between the two.

Named Aquilolamna milarcae – or the eagle shark – the creature was a member of the elasmobranch group of fishes, which includes modern sharks and rays. Although the cartilaginous skeletons of elasmobranchs typically don’t fossilize, they will occasionally do so under the right conditions.

Such was the case with the 93-million-year-old remains of an Aquilolamna, which were unearthed near the northern Mexican town of Vallecillo in 2012. A recent analysis by an international team of scientists determined that the skeleton was that of a previously unknown species.

The fossil remains of Aquilolamna milarcaeWolfgang Stinnesbeck

Like a shark, the creature had a streamlined “torpedo-shaped” body, and a tail with a longer upper lobe. But, like a ray, its pectoral fins took the form of wing-like appendages. It is therefore thought the animal used its tail for propulsion, and its “wings” for balance. The fossilized specimen, which was likely an adolescent, was 1.65 meters (5.4 ft) long and had a 1.9-m (6.2-ft) wingspan.

Additionally, the shark’s wide mouth and very small teeth strongly suggest that it fed on plankton … just as today’s whale sharks, basking sharks and manta rays do. Previously, paleontologists knew of only one other group of large plankton-feeding fish – pachycormidae – which swam the oceans during the Cretaceous period. The discovery of Aquilolamna milarcae bumps that number up to two.

A paper on the discovery was recently published in the journal Science. Lead scientist Dr. Romain Vullo, of France’s CNRS research institute, discusses the team’s findings in the video below.

https://youtu.be/lKaOiSue1-w

https://newatlas.com/biology/prehistoric-eagle-shark-ray/

Unexpected, ta.

> Named Aquilolamna milarcae – or the eagle shark – the creature was a member of the elasmobranch group of fishes, which includes modern sharks and rays. Although the cartilaginous skeletons of elasmobranchs typically don’t fossilize, they will occasionally do so under the right conditions.

Nice to see a fossil elasmobranch.

> Such was the case with the 93-million-year-old remains of an Aquilolamna, which were unearthed near the northern Mexican town of Vallecillo in 2012. A recent analysis by an international team of scientists determined that the skeleton was that of a previously unknown species. … The whale shark and the manta ray are perhaps two of the ocean’s most fascinating large fishes. Well, scientists have now announced the discovery of a prehistoric ancestor of both, that looked like a cross between the two.

93 million years. That’s unexpectedly recent for a common ancestor. Nicely ancient for a fossil. I wonder what other fossils and genetic evidence says.

“The earliest elasmobranch fossils came from the Devonian and many surviving orders date back to the Cretaceous, or even earlier. Many species … became extinct during the Permian, but the remaining sharks underwent a second burst of adaptive radiation during the Jurassic, around which time the skates and rays first appeared. Many surviving orders of elasmobranch date back to the Cretaceous, or earlier.”

Galeomorphii is a superorder of cartilaginous fishes which includes all modern sharks except the dogfish and its relatives.

Holocephali are the Chimaeriformes. This group includes the rat fishes in the genus Chimaera, and the elephant fishes in the genus Callorhinchus.

Squaliformes are the dogfish and other odd sharks illustrated below.

Batoidea is the superorder of cartilaginous fishes commonly known as rays.

In modern times, there are sharks and rays that look quite similar, eg. sawsharks and sawfishes. But neither look like Aquilolamna milarcae so this similarity must be convergent evolution if the fossil Aquilolamna milarcae is taken as a close relative of a common ancestor.

mollwollfumble said:

> Named Aquilolamna milarcae – or the eagle shark – the creature was a member of the elasmobranch group of fishes, which includes modern sharks and rays. Although the cartilaginous skeletons of elasmobranchs typically don’t fossilize, they will occasionally do so under the right conditions.

Nice to see a fossil elasmobranch.

> Such was the case with the 93-million-year-old remains of an Aquilolamna, which were unearthed near the northern Mexican town of Vallecillo in 2012. A recent analysis by an international team of scientists determined that the skeleton was that of a previously unknown species. … The whale shark and the manta ray are perhaps two of the ocean’s most fascinating large fishes. Well, scientists have now announced the discovery of a prehistoric ancestor of both, that looked like a cross between the two.

93 million years. That’s unexpectedly recent for a common ancestor. Nicely ancient for a fossil. I wonder what other fossils and genetic evidence says.

“The earliest elasmobranch fossils came from the Devonian and many surviving orders date back to the Cretaceous, or even earlier. Many species … became extinct during the Permian, but the remaining sharks underwent a second burst of adaptive radiation during the Jurassic, around which time the skates and rays first appeared. Many surviving orders of elasmobranch date back to the Cretaceous, or earlier.”

Galeomorphii is a superorder of cartilaginous fishes which includes all modern sharks except the dogfish and its relatives.

Holocephali are the Chimaeriformes. This group includes the rat fishes in the genus Chimaera, and the elephant fishes in the genus Callorhinchus.

Squaliformes are the dogfish and other odd sharks illustrated below.

Batoidea is the superorder of cartilaginous fishes commonly known as rays.

In modern times, there are sharks and rays that look quite similar, eg. sawsharks and sawfishes. But neither look like Aquilolamna milarcae so this similarity must be convergent evolution if the fossil Aquilolamna milarcae is taken as a close relative of a common ancestor.

>>93 million years. That’s unexpectedly recent for a common ancestor.<<

Not really, 93 million years is a very long time and for an animals that reproduces on an annual or bi-annul basis permits a huge number of generations that can mutate into other Genera.

>>“The earliest elasmobranch fossils came from the Devonian and many surviving orders date back to the Cretaceous, or even earlier. <<

Elasmobranch contains all cartilaginous fish of a group that comprises the sharks, rays, and skates. Aquilolamna is just a Genus of that group that evolved much later that those you refer.

>>In modern times, there are sharks and rays that look quite similar, eg. sawsharks and sawfishes. But neither look like Aquilolamna milarcae so this similarity must be convergent evolution if the fossil Aquilolamna milarcae is taken as a close relative of a common ancestor.<<

Aquilolamna cannot be an example of convergent evolution as the filter feeding whale shark and the manta ray evolved from it.