Starfish Fossil Stenaster

Stenaster sp. Extinct Starfish

Ktaoua Formation, Kaid Rami, Morocco
Ordovician Period - (450 millions years ago)
Stenaster is an extinct genus of brittle stars that lived from the Ordovician to the Silurian. Brittle stars or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long, slender, whip-like arms which may reach up to 60 cm (24 in) in length on the largest specimens. They are also known as serpent stars; the New Latin class name Ophiuroidea is derived from the Ancient Greek word meaning "serpent". The Ophiuroidea contain two large clades, Ophiurida (brittle stars) and Euryalida (basket stars). Over 2,000 species of brittle stars live today. More than 1200 of these species are found in deep waters, greater than 200 m deep.
Kingdom: Animalia
Phylum: Echinodermata
Subphylum: Eleutherozoa
Class: Ophiuroidea
Family: †Stenasteridae
Genus: †Stenaster