Cladoselache was a small prehistoric shark from the Devonian period, and with well-preserved specimens found in the "Cleveland Shale" on the south shore of Lake Erie. It was a predator of smaller fishes and cephalopods and was about 6 feet (2 meters) long. Several species are known. Cladoselache probably lived around reefs and rocks. Along with Stethacanthus, it was one of the earliest sharks on our planet.
Article by Brian Tinnon 12/14/2011
Differences From Modern Sharks
Cladoselache differed from most modern sharks in two ways:
Cladoselache lacked the 'claspers' seen on modern sharks. 'Claspers' are two fleshy projections on the underside of sharks used to help in reproduction. Exactly How Cladoselachee reproduced is hotly debated, as there is no fossil evidence of Cladoselache reproduction.
While modern sharks have a full body covering of scales, Cladoselache lacked scales except around the eyes, mouth and the edges of its fins.
In popular culture
Cladoselache had a cameo in the scene going to eat a Eusthenopteron in the 1940 movie Fantasia.