Edestus is an edestid eugenodontid cartilaginous fish from the Pennsylvanian of the United States of America, the United Kingdom, and Russia. It was named in 1855 by Joseph Leidy. It was a very strange eugenodontid notable for its shear-like jaws, and is often times confused for being a shark (despite being in a separate subclass).
Physiology[]
Edestus resembled a shark, with a torpedo-shaped body, triangular pectoral and dorsal fins, a crescent-shaped caudal fin, and a mid-sized head with big jaws. However, it had one major defining characteristic: its curved jaws had only one linear row of teeth, which gave them the appearance of a pair of pinking shears. Its body would have been covered in scaly skin.
Diet[]
Edestus was a predator, preying on smaller fish. Its shear-like jaws had serrated teeth designed for cutting prey, as well as for ripping them apart.
Ecology[]
Edestus's hunting method remains open to debate. Some speculate that it had just swam up to fish and cut them in half with its jaws, while others say that it swam at high speed to slam into them, much like a serrated battering ram. More recent studies seem to have shown that it probably used neither method, opening its jaws and thrashing them up and down to slash its prey into pieces instead. As well as this, unlike modern sharks, it did not shed worn teeth; rather, newer teeth grew in the back of its gums, eventually pushing the old teeth forward.