Physical Description

Ophiactis savignyi is a very small brittle star with a disc diameter of 0.5-11mm (McGovern 2002). This species usually has six arms that are either green or yellow-brown, with black stripes. The central disc is round and brown in colour, while the underside of the whole animal is white. There is no anus present, and the mouth is on the underside of the central disc (Hickman et al. 2011). The radial shields are large in proportion to this organism's size, and triangular. The oral shields of the disc and the arms are oval, while the aboral shields are laterally widened. Each segment of the arms bears six arm spines. For a more comprehensive description of O. savignyi and its physiology, refer to the 'Anatomy and Physiology' tab. 'A taxonomic guide to the brittle stars (Echinodermata, Ophiuroidea) from the state of Paraiba continental shelf, Northeastern Brazil' in ZooKeys, by Gondim et al. (2013) is a useful key for identifying this species.