Brittle stars, serpent stars, or ophiuroids (from Latin ophiurus 'brittle star'; from Ancient Greek ὄφις (óphis) 'serpent', and οὐρά (ourá) 'tail'; referring to the serpent-like arms of the brittle star) 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.

Amphiuroidea. Retrieved May, 22 2023, from en.wikipedia.org/wiki/Brittle_star.

Amphiuridae (commonly called long-armed burrowing brittle stars or burrowing brittle stars) are a large family of brittle stars of the suborder Gnathophiurina. Some species are used to study echinoderm development (e. g. Amphipholis kochii and Amphioplus abditus) and bioluminescence (the dwarf brittle star, Amphipholis squamata).

Amphiuridae. Retrieved May, 22 2023, from en.wikipedia.org/wiki/Amphiuridae.