Ophiacantha 4536

F 168073 (holotype), 168083, 168153, 146336, 82519, 82512, 82520, 82506, 82518.

Family - Ophiacanthidae.

Description

The disc is flat, 8 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 17–20 plates from the centre to the disc margin; primary plates not visible. Disc spines or granules of one type, cylindrical (with flat tips), with multiple, more than 3, terminal points/thorns, with thorns all over. The spines are up to 0.1–0.2 mm long, and 1–2 times high as wide; densely distributed (22–26 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, diamond or arrow head shaped, wider than long. The adoral shields are exposed, extending to lateral edge of oral shield, separated radially, meeting interradially. Bursal slits extend from the oral shield to the disc margin, not bordered by spines or papillae. The jaw is wider than long, with one, rounded apical papilla (tapering or straight to a rounded tip), longer than wide, with thorns. Oral papillae are present along each jaw angle in a series, pointed, thorned. The oral tentacle pore is located inside the jaw, with distal oral papilla enlarged, and rounded or triangular.

The specimen has five arms, unbranched, moniliform or basally constricted (slightly constricted), 3–5 times d.d., longest approximately 30–35 mm long, 2 mm wide at the base tapering to the tip. Dorsal arm plates, separated, without spines/granules (4–12 spines at the base of the arm on the dorsal surface); fan-shaped, 0.6–0.9 mm long, and 0.5–0.9 times long as wide. The first ventral arm plates are separated from the second plate, pentagonal, 0.5–0.7 mm long, and 0.9–1.2 times long as wide. The second ventral arm plates are separated from the third plate, triangular or fan-shaped, notched or concave laterally, 0.6–0.7 mm long, and 0.6–0.8 times long as wide. Ventral arm plates of the first free segments separated, fan-shaped (some with slightly notched distal edge), notched or concave laterally, 0.4–0.7 mm long, and 0.7–1 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, covering the pore, pointed. There are 4 arm spines on the first ventral segment, 6–7 on the first free segments. The spines are erect, extending around to the dorsal surface, longest dorsally, 1.3–2.9 mm long, 3–8 times long as wide, and 1–3 times as long as one arm segment, pointed, cylindrical. There are thorns, hapazardly on the spine surface, all along the spine, glassy rough shaft, with hooks (at tip and sometimes on shaft but not as prominent series). Spines also ventral spine specialised.

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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