Ophiurothamnus clausa

F 146301.

Family - Ophiacanthidae.

Description

The disc is flat, 5 mm diameter. The radial shields are round, contiguous over much of their length; 0.8–1.2 times long as wide, and length 0.14 times d.d. The dorsal surface is covered by plates, no spines/granules, with a visible diameter of 0.2–0.85 mm, overlapping or touching, with single interradial marginal plate; primary plates visible.

The ventral interradial surface is plated. The oral shields are exposed, teardrop, as long as wide. 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, pointed or tapering apical papilla, as wide as long. Oral papillae are present along each jaw angle in a series or separated by a gap from apical papillae, pointed. The oral tentacle pore is located inside the jaw, with distal oral papilla enlarged, and rounded or quadrangular.

The specimen has five arms, unbranched, basally constricted, 4–6 times d.d. Dorsal arm plates, separated, without spines/granules; diamond or fan-shaped, and 0.6–0.8 times long as wide. The second ventral arm plates are separated from the third plate, rounded or quadrangular, and 0.5–0.6 times long as wide. Ventral arm plates of the first free segments separated, quadrangular or fan-shaped, and 0.6–0.7 times long as wide. Tentacle pores along the arm, with one scale, covering the pore, oval. There are 2–3 arm spines on the first ventral segment, 7 on the first free segments. The spines are erect, extending around to the dorsal surface, longest dorsally, and 2–4 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 or hapazardly on the spine surface, all along the spine or on the tip or on the middle, glassy transparent shaft. Spines also ventral spine specialised (with prominant line of thorns along one edge).

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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