Ophioplocus Lyman, 1862

Alitto, Renata A. S., Bueno, Maristela L., Guilherme, Pablo D. B., Domenico, Maikon Di, Christensen, Ana Beardsley & Borges, Michela, 2018, Shallow-water brittle stars (Echinodermata: Ophiuroidea) from Araçá Bay (Southeastern Brazil), with spatial distribution considerations, Zootaxa 4405 (1), pp. 1-66 : 15

Genus Ophioplocus Lyman, 1862

Type taxon. Ophioplocus imbricatus ( Müller & Troschel, 1842) originally described as Ophiolepis imbricata .

Diagnosis. Disc covered by irregular and imbricated plates. Radial shields oval and smaller (approximately one tenth of dd), separated by several scales. One apical papilla. The number of lateral oral papillae variable, usually eight to ten. Bursal slits smaller, often bordered by papillae or scales. Dorsal arm plates divided into two or more. Two to seven tentacle scales in the first arm segment. Two to five arm spines arranged along the outer edge of the lateral arm plates ( Lyman 1865; Tommasi 1970; Thomas 1975).

Comments. Young specimens (less than 7.6 mm of dd) have been considered difficult to identify due to the presence of fewer arm spines, fewer tentacle scales, and less fragmentation of dorsal arm plates ( Thomas 1975). These characters have prompted many authors to describe new species and genera ( Lyman 1865; Koehler 1922). During past decades, Ophioplocus was alternately placed in two families, Ophiolepididae ( Tommasi 1970) and Ophiuridae ( Thomas 1975; Bernasconi & D’Agostino 1977; Borges 2006). However, Ophioplocus belongs to Hemieuryalidae due to its lateral arm plate morphology and molecular evidence ( O’Hara et al. 2017). Ophioplocus occurs in colder and deeper waters at depths> 30 m and are often found with Ophioderma ( Monteiro et al. 1992) . Currently, seven species are accepted in Ophioplocus ( Stöhr et al. 2016) , with one recorded from Brazil ( Barboza & Borges 2012): O. januarii ( Lütken, 1856) .