Fossils of Two New Big Mouthed Cretaceous Fish Species Discovered

Posted on February 8, 2016

Rhinconichthys big mouth Cretaceous fish

Scientists have discovered the fossils of two previously unknown species of plankton-eating fish from the Cretaceous Period, about 92 million years ago. The fish belong to the genus Rhinconichthys. The Rhinconichthys species was discovered in 2010.

The first species was discovered in England in 2010. New skulls were recently discovered in North American and Japan. The new species have been named R. purgatoirensis and R. uyenoi.

Kenshu Shimada, a paleobiologist at DePaul University and co-author of the study, says in a statement, "I was in a team that named Rhinconichthys in 2010, which was based on a single species from England, but we had no idea back then that the genus was so diverse and so globally distributed."

Rhinconichthys belongs to an extinct bony fish group called pachycormids. It was believed to be over 6.5 feet long and had a plankton diet. The unusual bony fish had a pair of bones called a hyomandibulae which formed a massive oar-shaped lever to protrude and swing the jaws open so it could swallow plankton-rich water.

Rhinconichthys jaws showing hyomandibulae

A research paper on the new species was published here in the journal, Cretaceous Research.

Image: Robert Nicholls

Illustration: Kenshu Shimada