Ophiuroidea Protasteridae

The family Protasteridae is an extinct group of ophiuroids (class Ophiuroidea), commonly known as brittle stars or snake stars. TAll members of the Protasteridae family are extinct. They lived during the Paleozoic, and fossils have been found dating from the Ordovician to the Carboniferous (Mississipic). They differed from modern ophiuras (Ophiurida) in the structure of their arms. Instead of a single central column of vertebral ossicles, protasterids had two alternating rows of supports along each arm, giving them a "zipper" appearance.