Amphiura callida is a species of brittle star

Brittle star

Brittle stars or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the seafloor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to in length on the largest specimens...

 belonging to the family Amphiuridae

Amphiuridae

Amphiuridae are a large family of brittle stars of the suborder Gnathophiurina. Some species are used to study echinoderm development Amphiuridae (commonly called long-armed burrowing brittle stars or burrowing brittle stars) are a large family of brittle stars of the suborder Gnathophiurina. Some...

. It is only known from the continental shelf

Continental shelf

The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 off the coast of Cabo Frio

Cabo Frio

Cabo Frio is a Brazilian municipality in Rio de Janeiro state, founded by the Portuguese on November 13, 1615.The city's economy is mainly based on tourism, as most of the cities situated in the called Região dos Lagos . The city is usually visited by people from Minas Gerais, Brasília and Rio de...

, southeastern Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

 (depth 50 m).

This is a rather robust brittle star with a disc diameter of up to 10 mm and an arm length of up to 45 mm. It can be distinguished from its congeners from the leaf-like shape of the distal oral papilla

Papilla (fish mouth structure)

The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...

e and the presence of groups of two to seven spines along the entire length of the arm.