Disk circular (dd = 1.30 to 6.90 mm). Covered by imbricating scales of different sizes, largest between radial shields and on interradial margin of disk (Fig. 12a). Radial shields narrow, long, broadly separated, distal end slightly broader, distinct from remaining disk because of their white coloration (Fig. 12a). Numerous olive-green patches on the dorsal and ventral sides of the disk (Fig. 12a). Ventral interradius with scales similar to dorsal disk surface (Fig. 12b). Bursal slits broad and elongated. Oral shields large, diamond-shaped, laterally broadened, some with a dark spot on distal margin. Two spatulate oral papillae (Fig. 12c), borders slightly denteate, on each margin of jaw, the outer one slightly longer. A cluster of dental papillae on apex of jaw (Fig. 12c). Dorsal arm plate slightly wider than long, distal border slightly wider than anterior border (Fig. 12d). Ventral arm plate longer than wide, pentagonal, posterior margin concave (Fig. 12e). Two tentacle scales (Fig. 12b, e), outer smaller and inner longer, flattened and overreaching median ventral plane of arm. Tentacle pore large. Four to six arm spines, ventral one longest and slightly curved (Fig. 12d, e). Remaining spines decrease in size ventralwards, with small denticles at apex. Two close brown stripes on lateral arm plate, and a lighter median band on the dorsal arm plate (Fig. 12a, d). Ventral surface sometimes with two brown stripes close to insertion of spines.

Florida Keys, the Mexican Caribbean, the Antilles, Costa Rica, Colombia, Venezuela, and Brazil (Hendler et al. 1995, Alvarado et al. 2008, Borrero-Pérez et al. 2008). In Brazil, from Abrolhos off southern Bahia (Tommasi 1970). From 12 to 161m (Hendler et al. 1995). Recorded 12 and 30 m in present account.

Typically, this is a coralline bottom species (Tommasi 1970). Abreu-Pérez et al. (2005) also record the species for sandy substrates and on rocks and corals. We record this species mainly in rhodolites. Ophiopsila hartmeyeri showed a mosaic distribution of characters described for Ophiopsila maculata (Verrill, 1899), and Ophiopsila riisei Lütken, 1859. Ophiopsila hartmeyeri was similar to Ophiopsila maculata in having black dots on each oral shield, originally diagnosed by Tommasi (1970). Comparing Ophiopsila hartmeyeri with Ophiopsila riisei, both share these black spots also on the dorsal surface of the disk, a character previously considered diagnostic for Ophiopsila riisei (Koehler 1913). The specimens of Ophiopsila hartmeyeri from the Paraíba coast have a smaller number of spines (four or six) than that recorded in the literature (eight arm spines). However, their shape is characteristic for Ophiopsila hartmeyeri (sword-shaped). In the present study we follow the older classification, in which the genus Ophiopsila belong to the family Ophiocomidae, as this genus does not have a pair of infradental papillae (diagnostic character of Amphiuridae), but has tooth papillae (a cluster of short, granule-like apical papillae on the dental plate) (one of the diagnostic characters of Ophiocomidae). Martynov (2010) proposed transfering the genus Ophiopsila to the familyAmphiuridade on the basis of the morphology of the lateral arm plate. Murakami (1963), in his exaustive study on the dental and oral plates, suggests that the dental plate of the genus Ophiopsila is most closely related to the family Ophionereididae. The systematic position of Ophiopsila is thus still uncertain and needs further studies.