A multi-institution team of researchers has discovered the newest, biggest member of a group of extinct, armor-plated fish called Antiarchi.
The new fish, Bothriolepis rex, dates to the Devonian Period, some 370 million years ago, and swam Earth's oceans long before dinosaurs were on the scene. Bony plates covered its front fins, shoulders and head, and its size – about 5.5 feet long – makes it the new top fish among Antiarchs, surpassing Bothriolepis maxima by about 30% in length.
Researchers from Drexel University, Delaware Valley University, Stanford University and the University of Chicago collaborated on the discovery and have published their findings about the ancient fish in the Journal of Vertebrate Paleontology.
The fossils used to describe the fish were found on Ellesmere Island in Nunavut, Canada and included the bony, thick plates that covered the ancient creature's head. The plates probably gave B. rex a measure of protection from the bites of large predatory fish called sarcopterygians, say the researchers.
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The fish wasn't the violent type. It may have a "rex" in its name, but B. rex was no kind of fierce hunter. Instead, the scientists say, it was, like others in the Bothriolepis genus, a bottom-feeder that cruised the sandy sea floor picking up dead plant and animal matter.
With a flattened underside and a downward-angled mouth, "it was not equipped for active predation," said the study's lead author Jason Downs, of Delaware Valley University, in a statement.