Amphiodia habilis 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 a single locality off the coast of 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...

, near the mouth of the Doce River

Doce River

The Doce River is a river in southeast Brazil, which has an extension of 853 km.It is formed by the junction of the Piranga and the Carmo near the historical city of Ouro Preto, whose sources are located in the foothills of the Mantiqueira and Espinhaço mountain chains at altitudes of about 1,200...

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This brittle star, with a disc diameter of 3.5 mm and arm length of 20 mm, can be most readily distinguished from congeners by the thick disc with large armoured plates on the upperside.