Ancient Chimeras Were Suction Feeders, Not Shell Crushers

A rare three-dimensional fossil of an ancient chimera has revealed new hints of the diversity of these creatures in the Carboniferous time, some 300 million years ago.

Ancient chimera

A research study led by the Muséum national d’histoire naturelle (MNHN) and the University of Birmingham revealed an ancient relative of chimeras– jawed vertebrates that are related to sharks and rays– fed by sucking in prey animals undersea.

The fossil, from a genus known as Iniopera, is the identified only suction feeder among chimeras and quite distinct from living chimeras, which feed by crushing mollusks and also other hard-shelled prey between their teeth. The research study is published in the journal PNAS.

Fossil evidence

According to Dr. Richard Dearden, lead researcher on the paper at the University of Birmingham, having the ability to identify Iniopera as a suction feeder enlightens the diverse role of chimeras in these early ecosystems. Particularly, it suggests that in their early evolutionary history, some chimeras were inhabiting ecological niches that are currently monopolized by ray-finned fishes– a far cry from their modern life as specialized shell-crushers.

Due to chimeras’ skeletons composition of mainly cartilage, their fossil remains are usually flat and, therefore, difficult to extract info from. However, from studying the diverse body and also tooth shapes, scientists already understood that there were far more, more different species of chimera living in the Carboniferous than there are today.

Utilizing 3D imaging techniques, the group reconstructed the head, shoulder, and also throat skeleton of the fossil. Afterwards, they estimated the location of major muscles and discovered the anatomy was poorly suited to crushing hard-shelled prey. Instead, the scientists believe the animal was more likely to have utilized the muscle arrangement to expand the throat to take in water and also a forward-pointing mouth to orient towards the prey.

Suction feeding

Suction feeding is a strategy used by many animals that live underwater. It entails producing low pressures in the throat to pull in water and prey. To do this effectively, the animal requires to be able to quickly expand its throat and point its mouth forward towards prey items. Various distinct marine jawed vertebrates, such as ray-finned fishes and some turtles, have evolved specialized anatomies to help them suction feed more effectively.

The suction feeding concept proposed by the group also fits with other proof, including arthropods preserved inside the stomach of other specimens.

Read the original article on PHYS.

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