Team Finds Two Fossils of Incredibly Big-Mouthed Bony Fish

An international research team found two fossils of incredibly big-mouthed bony fish that must have fed on plankton during the time dinosaurs roamed the Earth. Scientists classified the fossils as belonging to the Rhinconichthys genus.

Kenshu Shimada, co-author of a study on the new findings and paleobiology expert with the DePaul University in Chicago, explained that species of the Rhinconichthys genus are not a common sight. Until the latest discovery, researchers knew of only one species, which was discovered in England.

But researchers recently found another specimen in Colorado, while a reanalysis of old data on a Japanese skull showed that the skull also belongs to the Rhinconichthys genus. This is how now researchers have three members of the genus, and three different regions where the ancient animals might have lived: North America, Japan, and England.

The two new species were scientifically dubbed R. uyenoi and R. purgatoirensis.

Shimada said that he was part of the group that gave the name to the English specimen in 2010. This means that the Rhinconichthys genus emerged from a single known species. So, study authors were thrilled to learn that the genus is more diverse. They were also stunned to learn that specimens lived in such remote places across the globe.

Study authors explained that all species of fish were suspension feeders, i.e. aquatic animals that feed on tiny organisms that float freely, are suspended in water. They are also bony fish i.e. they have a skeleton made of bones rather than cartilages as most fish do. Plus, they were extremely specialized at how they fed, having extraordinarily big mouths that allowed them to capture more prey in a single move.

A research paper on the new species will be published in the next issue of the journal Cretaceous Research.

The researchers involved in the recent discovery have very different backgrounds. Some of them are from state-run agencies such as the United States Forest Service, whose senior paleontologist Bruce A. Schumacher discovered the Colorado species. Others researchers are from museums, universities and research centers from the U.S. and Europe.

Members of the Rhinconichthys genus are now an extinct group of impressively large bony fish. According to researchers’ conclusions drawn after analyzing the animals’ skulls, the creatures must have been about 6.5 foot long.

But the most unsusual aspect of their body was their mouth. A huge oar-shaped jaw bone helped the mouth open like a parachute to allow more plankton-filled water to reach the fish’s mouth.

Image Source: UPI