Ophiopezidae O’Hara, Stöhr, Hugall, Thuy & Martynov, 2018

Goharimanesh, Mona, Stöhr, Sabine, Mirshamsi, Omid, Ghassemzadeh, Fereshteh & Adriaens, Dominique, 2021, Interactive identification key to all brittle star families (Echinodermata; Ophiuroidea) leads to revised morphological descriptions, European Journal of Taxonomy 766 (1), pp. 1-63 : 35

Family Ophiopezidae O’Hara, Stöhr, Hugall, Thuy & Martynov, 2018

Type genus

Ophiopeza Peters, 1851 .

Other genera

Ophiochaeta Lütken, 1869 .

Description

ARM.Arm shape unbranched; length more than4×disc diameter;covering without granules/spines/tubercles. Arm combs absent. Dorsal arm plate present. Accessory dorsal arm plate absent. Ventral arm plate present. Accessory ventral arm plate absent. Girdle of tiny hooks on the arms absent. Spines all similar in shape. Arm spine cross section round. The ratio of thickness of distal ⅓ of arm spine to maximum thickness (in a given cross-sectional plane) 0.6–0.9. Arm spines pointed; mainly lateral; predominantly parallel to arm axis (adpressed). Longest arm spines shorter than half a segment. Tentacle scales present; pores visible along most of the arm; slightly longer than wide; shorter than the spine nearby. Dental plate ventral half widest; entire (single plate). Position of lateral arm plate (LAP) only lateral. Dorsal and/or ventral edge(s) of LAPs without constriction. Ventral position of LAP not projecting ventro-proximalwards. Ventro-distal tip of LAP not projecting ventralwards. Arm spine articulation with dorsal and thin ventral lobes and a fully developed sigmoidal fold; arranged over entire distal LAP edge; larger in middle of arm. Distance between spine articulations equal. Nerve and muscle openings separated by large, prominent ridge or regular stereom. Nerve opening smaller than muscle opening.

DORSAL DISC. Disc pentagonal; flat (about same level as arms). Integument obscuring plates. Dorsal disc with granules; with concealed primary plates; without scales; with spines. Dorsal disc scale/plate without tubercles. Radial shield present; covering, length and shape no data.

VENTRAL DISC. Gonads restricted to the disc. Ventral interradii with granules. Scales on ventral interradii absent. Ventral teeth several (tooth papillae). Infradental papillae on oral plate present. Buccal scales on OP absent.Accessory oral papillae on OP absent. Lateral oral papillae on OP present; single row of lateral papillae; spiniform. Adoral shield spine present. Lyman’s ossicle present. Oral shield covering less than one third of interradius; about as long as wide. Madreporite no data. Adoral shield separated. Abradial genital plate not twisted. Number of genital slits one per bursa. Genital slit longer than half the length of an interradius. Genital papillae absent. Dental sockets slit-shaped or circular; less than 50% of the width. At least one socket on DP as depression or perforation without septum. Teeth spine-shaped. Teeth on DP arranged as a single row on ⅔ and a cluster of tooth papillae on ⅓ of dental plate.

VERTEBRAE. Vertebrae zygospondylous; beyond segment 5 with short keel; without oral bridge.