Trochodota epiphyka O’Loughlin, 2007

O’Loughlin, P. Mark, 2007, New apodid species from southern Australia (Echinodermata: Holothuroidea: Apodida), Memoirs of Museum Victoria 64, pp. 53-70 : 62-66

Trochodota epiphyka O’Loughlin sp. nov.

Figure 2b, 8b, e–f, 9

Trochodota allani .— O’Loughlin, 1984: 155.— Rowe, 1995: 268

(part) (non Trochodota allani ( Joshua, 1912))

Material examined. Holotype: Victoria, Flinders, Mushroom Reef, sieved from Amphibolus in rocky shallows, A. Falconer, 20 Apr 2007, NMV F132690 (photo live by Leon Altoff).

Paratypes: (all paratype specimens from algal scrapings in the rocky shallows, collected by M. O’Loughlin). Flinders, West Head, M. Benavides-Serrato, D. Maric, M. O’Loughlin, 27 Jan 2007, F121896 (1); F121897 (1); Flinders, ocean platforms, 13 Apr 1985, F73564 (1); 13 Jul 1990, F73565 (1); 16 Nov 1980, F73566 (3); 10 Mar 1980, F73567 (1); 7 Apr 1980, F73568 (3); 6 Mar 1982, F73586 (1, photo by I. Kirwan); 17 Feb 1990, F73587 (5).

Other material (selection). Victoria, Cape Paterson, 25 Jan 1992 , F59230 (2); 18 Jan 1980, F73590 (4); Mullet Holes ( 10 km NE of Apollo Bay ), 2 Jan 1988 , F73584; Portland, W side of Bridgewater Bay , 25 Feb 2007 , F125372 (1, photo live by Leon Altoff). N Tasmania, Lulworth, Black Rock Point, 22 Nov 1982 , F82765 (5). South Australia, Robe, 10 Jan 1988 , F82766 (3); Victor Harbor, The Bluff, 9 Nov 1988, F82720 (4); Cape Jervis, 10 Nov 1988, F82769 (1); Kangaroo I., Emu Bay , 17 Jan 1990 , F82768 (3). Western Australia, Cape Naturaliste, Eagle Bay , 25 Feb 1975, WAM Z464–76 (1).

Description. Up to 14 mm long, 2 mm diameter (preserved); anterior dorsal body and tentacles overhang ventral body and tentacles; tentacles digitate, 10, each with predominantly 3 pairs of digits, longest pair distally, shortest pair proximally; calcareous ring with 5 radial 5 interradial plates all fused to form narrow ring; radial plate subrectangular with narrow short truncate anterior projection, shallow concave posterior indentation; interradial plate asymmetrical with mid-anterior small notch and short projection, concave indentation posteriorly; single dorsal stone canal, hook-shaped madreporite; 1 polian vesicle, ventral; 2 narrow bands of ciliated funnels along left lateral interradius adjacent to left ventrolateral muscle, and along right ventral interradius adjacent to midventral muscle; 2 unbranched gonad tubules, 1 on each side of dorsal mesentery, joined dorsally at shared gonoduct.

Body wall ossicles wheels, sigmoid hooks: wheels in dorsal and lateral interradii, no wheels in 2 ventral interradii, not grouped into papillae, wheels with 6 spokes, rarely more, outer rim of wheels with rounded hexagonal form, inner rim not parallel to outer rim, undulating, wide across spokes with continuous teeth, narrow between spokes and lacking teeth at narrowest part, wheel diameters 40–160 μ m; sigmoid hooks evenly distributed around body, outer side of curved hooks with short parallel series of minute spinelets, hook lengths 88–136 μ m. Tentacles with rod ossicles: rods curved, slightly tapering distally, ends with short lobed branches, rods with irregular side denticulations, papillate to short columnar to bifurcate, some flared distally, often with small spinelet apically, rod lengths 64–80 μ m.

Colour (live). Body white, cream or grey, with dark flecks or broken bands of purple, brown or black; tentacles white.

Distribution. From Cape Paterson (eastern Victoria) to Cape Naturaliste (south-western Australia), northern Tasmania; shallow sub-littoral on algae.

Etymology. From the Greek epi (upon) and phykos (seaweed, alga), referring to the microhabitat of the species (feminine).

Remarks. In contrast with the small size and broken colours of Trochodota epiphyka O’Loughlin sp. nov., Joshua (1912) reported T. allani to be 80 mm long and 6 mm wide, and described the live colour as carmine and blood red ( Joshua, 1914). T. epiphyka is distinguished in the key above from the other two species of Trochodota in southern Australia.