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Ophiomitrella 2732

F 168076 (holotype), 168094, 168186, 144701, 82553, 159767, 146333, 168188, 82555.

Family - Ophiacanthidae.



Description

The disc is flat, 13.8 mm diameter. The radial shields are triangular with rounded corners, separated and parallel to one another, with 1–2 plates between them; 1.8–2.6 mm long, 1.1–1.6 times long as wide, and length 0.13–0.19 times d.d. The dorsal surface is covered by plates, bearing spines/granules, with a visible diameter of 0.4–2 mm, overlapping, and 10–12 plates from the centre to the disc margin; primary plates not visible. Disc spines or granules of one type, cylindrical or dome-shaped, with thorns all over. The spines are up to 0.3–0.5 mm long, and 1.1–1.6 times high as wide; sparsely distributed (1 per plate), not covering the radial shields.

The ventral interradial surface is plated, with a few spines extending under from the disc margin. The oral shields are exposed, teardrop, 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, pointed or tapering apical papilla, longer than wide, with thorns. Oral papillae are present along each jaw angle in a series or separated by a gap from apical papillae, pointed, thorned. The oral tentacle pore is located inside the jaw, with distal oral papilla enlarged, and triangular or quadrangular.

The specimen has five arms, unbranched, moniliform, 4–6 times d.d., longest approximately 65–80 mm long, 4 mm wide at the base tapering to the tip. Dorsal arm plates, contiguous or separated (contiguous first few segments), with spines/granules (1–3 loose on the first plate), clustered on the basal dorsal arm plates; fan-shaped, 0.9–1.3 mm long, and 0.8–1.1 times long as wide. The first ventral arm plates are contiguous with the second plate, pentagonal, 0.7–0.8 mm long, and 0.7–0.9 times long as wide. The second ventral arm plates are separated from the third plate, fan-shaped (roughly), notched or concave laterally, 0.8–1 mm long, and 0.5–0.7 times long as wide. Ventral arm plates of the first free segments separated, quadrangular or hexagonal, notched or concave laterally (slightly), 0.8–1 mm long, and 0.6–0.7 times long as wide. The lateral arm plates touch one another laterally, or meet on the dorsal and ventral midlines (nearly touching on the ventral midline). Tentacle pores along the arm, with one scale, covering the pore, oval. There are 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, 3.2–3.9 mm long, 11–18 times long as wide, and 2–3 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 (clear on some spines, others appear haphazard due to more thorns present, larger triangular thorns on some series), all along the spine, glassy transparent shaft. Distal ventral arm spines with a prominent longitudinal series of thorns on one side.

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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