ophionid

Ophionid is a term sometimes used colloquially to refer to a group of marine invertebrates belonging to the phylum Echinodermata, specifically the brittle stars or ophiuroids. Brittle stars are characterized by their distinct central disc and five (or sometimes more) slender, flexible arms that are sharply demarcated from the disc. Unlike their close relatives, the sea stars, their arms are not fused to the central body. These animals are found in all oceans, from the intertidal zone to the deep sea, and exhibit a wide range of habitats and lifestyles.

The name "ophionid" derives from the scientific genus Ophionereis, which is a representative genus of brittle stars. However, the term is not a formal taxonomic classification but rather a descriptive or informal grouping. Brittle stars typically move by lashing their arms and are often scavengers or detritivores, feeding on small particles of organic matter. Some species are suspension feeders, while others are predators. Their skeletal plates, called ossicles, provide protection and support. The diversity within the Ophiuroidea class is vast, with thousands of described species, showcasing a remarkable array of appearances and adaptations.