Ophiactis savignyi (Müller & Troschel 1842)

Six arms. Disk circular (dd = 1.3 mm). Covered by numerous imbricating scales. Some small spines on scales at margin of disk (Fig. 8g). Radial shields large, triangular, contiguous (Fig. 8g). Ventral interradus with some spines on the scales (Fig. 8h). Bursal slit enlarged. Oral shields oval (Fig. 8i). Adoral shields widened laterally. One oral papilla on each side of jaw angle (Fig. 8i). Apical papilla well developed. Dorsal arm plate wider than long, sometimes subdivided into two plates (Fig. 8j). Ventral arm plate octogonal. Six arm spines, with denticles along margin and at tip (Fig. 8l). Single tentacle scale semi-elliptical (Fig. 8l).

Disk rounded (dd = 1.1 to 5 mm) and covered by large imbricated scales and short scattered spines over and at the edge of disk. Radial shields large, triangular and joining distally (Fig. 3J). Ventral interradius with scales and scattered spines (Fig. 3K). Oral shields diamond shaped with rounded edges. Adoral shields small and not meeting proximally. Two flattened oral papillae in each side of the jaw (Fig. 3L). Five or six arms. Dorsal arm plates wider than long with rounded edges (Fig. 3H). Ventral arm plates quadrangular with rounded edges. Five to six short, rugose and spinulose arm spines. Single, rounded, lanceolated tentacle scale (Fig. 3I). Color of the disk olive greenish-brown, with darker radial shields (Fig. 3G). Ventral side cream (Fig. 3K).

Cosmopolitan, in warm waters throughout the western Indo-Pacific, eastern Pacific, including Malpelo Island off western coast of Colombia, and both sides of the Atlantic, including Ascension island in the South Atlantic. Western Atlantic from South Carolina, Bermuda, Mexican Caribbean, Honduras, and Brazil (Devaney 1974, Pawson 1978, Hendler et al. 1995, Durán-Gonzáles et al. 2005, Cohen-Rengifo et al. 2009). In Brazil from Amapá, Pará, Maranhão (Albuquerque 1986), Ceará (Lima-Verde 1969), Paraíba (Gondim et al. 2008), Pernambuco (Tommasi 1970), Alagoas (Miranda et al. 2012), Bahia (Alves and Cerqueira 2000), Abrolhos off southern Bahia (Tommasi 1970), Rio de Janeiro (Brito 1960), and São Paulo (Tommasi 1970). Intertidal to 518 m. Found at 10 m in this study.

Cosmopolitan. Indo-Pacific, Eastern Pacific and both sides of the Atlantic. In the Eastern Pacific, the species has been recorded in the Hawaiian Islands, Mexico, Costa Rica, Panama, Colombia, Galapagos Islands and Peru (Clark HL 1915, Nielsen 1932, Maluf 1988, Hendler et al. 1995, Alvarado and Fernández 2005, Neira and Cantera 2005). In Mexico from the Gulf of California, on the Pacific side of Baja California and Baja California Sur, Nayarit, Marías Islands, Jalisco, Colima, Revillagigedo Islands, Michoacán, Guerrero and Oaxaca (Brusca 1980, Honey-Escandón et al. 2008). Commonly found in shallow water up to 518 m (Hendler et al. 1995). In this study, Ophiactis savignyi was collected on coral reefs from Nayarit, Jalisco, Colima, Michoacán, Guerrero and Oaxaca; between 2.3 to 26 m depth.