Carboniferous Sharks

a bunch of fish, including a shark, in a forrest of sea lilies
(Julius Csotonyi, Smithsonian Institution)

The first creatures with backbones emerged during the Paleozoic Era. Here, the shark (Edestus heinrichi) pursues its prey (Iniopera richardsoni). Stethacanthus altonensis, the shark with the unusually shaped dorsal fin, glides among the sea lilies below. In the distance, another giant shark (Glikmanius occidentalis) glides by.