Ophiacantha 4541

F 93303 (holotype), 93304, 93305.

Family - Ophiacanthidae.

Description

The disc is tumid, 3 mm diameter. The radial shields are covered. The dorsal surface is covered by plates, bearing spines/granules, with a visible diameter of 0.2–0.4 mm, overlapping, and 10 plates from the centre to the disc margin; primary plates not visible. Disc spines or granules of one type, cylindrical, and glassy transparent shaft, with thorns all over. The spines are up to 0.6–0.8 mm long, and 8–14 times high as wide; sparsely distributed (9–12 per sq mm), covering the radial shields.

The ventral interradial surface is plated, with spines/granules also covering the surface. The oral shields are exposed, fan shaped or diamond (difficult to distinguish), wider than long or as long as wide. The adoral shields are exposed, extending to lateral edge of oral shield, separated radially, meeting interradially. Bursal slits absent. The jaw is as wide as long (edges touch one another), with one, pointed or tapering apical papilla, longer than wide, with thorns. Oral papillae separated by a gap from apical papillae, pointed, thorned. The oral tentacle pore is located inside the jaw (at top of jaw edge), with distal oral papilla similar to other oral papillae (difficult to distinguish).

The specimen has five arms, unbranched, basally constricted (slightly), 1–2 times d.d. (incomplete), longest approximately 2 mm long, 0.5 mm wide at the base tapering to the tip. Dorsal arm plates, separated, without spines/granules; fan-shaped or trapezoid (rounded distal edge), 0.2–0.3 mm long, and 0.7–1 times long as wide. The first ventral arm plates are separated from the second plate, fan, 0.1–0.2 mm long, and 0.6–1.1 times long as wide. The second ventral arm plates are separated from the third plate, fan-shaped, notched or concave laterally, 0.1–0.2 mm long, and 0.8–1 times long as wide. Ventral arm plates of the first free segments separated, fan-shaped, notched or concave laterally, 0.1–0.2 mm long, and 0.8–1 times long as wide. The lateral arm plates touch one another laterally, or meet on the dorsal and ventral midlines. Tentacle pores along the arm, with one scale, not covering the pore, oval. There are 0–1 arm spines on the first ventral segment, 2 on the first free segments. The spines are erect, extending around to the dorsal surface, longest dorsally, 0.5–0.6 mm long, 8–9 times long as wide, and 1–2 times as long as one arm segment, pointed, cylindrical. There are thorns, in longitudinal series on the surface from the base to the tip of the spine, all along the spine, glassy transparent shaft.

Description exported from Delta key and to be finalised when DNA sampling completed. Note species description and image characters may vary slightly in animals of different size within the same species.

Cite this publication as: "T O'Hara (2010). ‘Ophiuroids from deep sea southern Australia. Museum Victoria. Version: 1.0 http://www.museumvictoria.com.au/stars"
Information updated 5 February 2010

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