Ophiopteridae 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 : 31-32

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

Type genus

Ophiopteris E.A. Smith, 1877 . (No other genera)

Description

ARM. Arm shape unbranched; length 3–4× 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 present. Girdle of tiny hooks on the arms absent. Spines all similar in shape. Arm spine cross section round, or oval. The ratio of thickness of distal ⅓ of arm spine to maximum thickness (in a given cross-sectional plane) 0.9–1. Arm spines flat or cylindrical; mainly lateral; predominantly erect, standing perpendicular to arm axis. Longest arm spines longer than two segments. Tentacle scales present; pores visible along most of the arm; nearly as long as wide; shorter than the spine nearby; cross section round. Position of lateral arm plate (LAP) arched (wrapped around the arm). Dorsal and/or ventral edge(s) of LAPs without constriction. Ventral position of LAP projecting ventroproximalwards. Ventro-distal tip of LAP projecting ventralwards. Arm spine articulation with dorsal and ventral lobes; with 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 small ridge if at all. Nerve opening smaller than muscle opening.

DORSAL DISC. Disc pentagonal or circular; high (above arm level). Integument obscuring plates. Dorsal disc with granules; with concealed primary plates; with scales; without spines. Dorsal disc scale/plate without tubercles. Radial shield present; with granules; length more than half of the disc radius; scalene (oblique) triangular.

VENTRAL DISC. Gonads restricted to the disc. Ventral interradii with spines. 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 more than one third of the length of an 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 plate dorsal half widest; entire. Dental sockets heart-shaped(?); equal to or more than 50% of the width. Teeth flat (with round or slightly pointed tip, but never spine-like).

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