This Ancient Shark Looked Like an Eel and Swallowed Its Prey Whole
by Jason Daley Smithsonian.com
Almost everything paleontologists know about ancient sharks comes from their teeth. That’s because the animals had skeletons made of cartilage, which does not fossilize as easily as bone. So researchers were surprised to find several shark skulls and an almost complete skeleton of 360-million-year-old primitive shark in the Atlas Mountains of Morocco.
The fossils, described in the journal Proceedings of the Royal Society B, come from two species of sharks in the genus Phoebodus, which went extinct during the Caroboniferous Period about 299 to 359 million years ago, leaving behind no known ancestral species. Bob Yirka at Phys.org reports that prior to the discovery, Phoebodus sharks were only known from three teeth.
These fossils survived because the area where the animals died was a shallow sea basin. Their bodies were covered in sediment and limited water circulation and low oxygen levels allowed them to fossilize without being destroyed by predators or broken down by bacteria.
Still, the fossils were fragile, so the team chose to examine them using a CT scan instead of chipping them out of the rock. The imaging reveals a very strange, un-shark-like creature.