Rugathanas borradailei (Coutière, 1903)

Figure 3

Remark: Synonymy below from Anker & Jeng (2007), updated and corrected

Arete Borradailei Coutière 1903: 80, figs. 19–24; Coutière 1905a: 737; Coutière 1905b: 861, fig. 133.

Athanas borradailei – Banner & Banner 1960a: 138; Jacquotte 1964: 180; Banner & Banner 1966: 152; Banner & Banner 1983: 73; Chace 1988: 61.

Rugathanas borradailei – Anker & Jeng 2007: 48, figs. 1–3, 6a.

Arete ghardaqensis Ramadan 1936: 15, pl. 1, figs. 2–8.

Athanas ghardaqensis – Banner & Banner 1960a: 138; Banner & Banner 1981: 42.

Athanas polynesia Banner & Banner 1966: 152, fig. 7; Banner & Banner 1982: 302, fig. 93.

Material examined. French Polynesia, Society Islands. 1 male (CL 2.20 mm), FLMNH UF Arthropoda 16327, Moorea, lagoon between Cook’s Bay and Sheraton Hotel, 17.4764˚ S, 149.8327˚ W, outer reef slope, spur and groove zone, from large dead Acropora, depth: 4–7 m, coll. C. McKeon, J. Moore, processed by A. Anker, 10.XI.2008 [BMOO-fcn 5251]; 1 ovigerous female (CL 2.05 mm), FLMNH UF Arthropoda 16326, same collection data as for previous specimen [fcn BMOO-5250].

Additional material examined. 1 male (CL not measured), FLMNH UF Arthropoda 17331, Australia, Queensland, Lizard Island, Hicks Reef, 14.4480˚ S, 145.4992˚ W, fore reef, brushing of large Pocillopora head, depth: 5–7 m, coll. M. Blazewicz, processed by A. Anker, 21.II.2009 [fcn LIZ-1515]; 1 male (CL not measured), FLMNH UF Arthropoda 11165, Line Islands, Northern Fanning Group, Kingman Reef, southern shore of atoll, 6.3796˚ N, 162.3648˚ W, outer reef slope, from dead coral head ( Pocillopora verrucosa ?), depth: 16–17 m, coll. G. Paulay, N. Knowlton and others, 28.VIII.2005 [fcn MSR-145]; 1 ovigerous female (CL not measured), FLMNH UF Arthropoda 11159, Line Islands, Northern Fanning Group, Kingman Reef, north-eastern side of atoll, 6.4358˚ N, 162.3822˚ W, outer reef slope, from dead coral head ( Pocillopora verrucosa ?), depth: 0–12 m, coll. G. Paulay, N. Knowlton and others, 27.VIII.2005 [fcn MSR-66].

Description. See Coutière (1903, 1905b), as Arete borradailei; Ramadan (1936), as Arete ghardaqensis; Banner & Banner (1966, 1982), as Athanas polynesia; see also Banner & Banner (1983) for synonymy and Anker & Jeng (2007) for diagnosis and additional illustrations.

Colour pattern. Semitransparent, speckled with red or orange-red chromatophores, sometimes forming diffuse transverse bands on abdomen (Fig. 3); eggs / fresh embryos bright green (Fig. 3 B). See also colour description and photograph in Anker & Jeng (2007).

Type locality. Hulule Male Atoll, Maldives.

Ecology. In crevices in dead corals, often Pocillopora and Acropora; sometimes also in boreholes made by the sea urchin Stomopneustes variolaris Lamarck, 1816 (Jacquotte 1964), at depths ranging from intertidal to at least 12 m; probably lives in male-female pairs.

Distribution. Indo-West Pacific: Red Sea, East Africa, Madagascar, Maldives, Mascarene Islands, Philippines, Ryukyu Islands, Taiwan, Australia, Samoa (Anker & Jeng 2007); herewith range extended to the Society Islands (Moorea), French Polynesia, and the northern Line Islands (US territory).

Remarks. Rugathanas borradailei is apparently widespread in the Indo-West Pacific, but is either not very common or easily overlooked due to its small size and semi-translucence. This species has been collected only once in a sampling period of almost six weeks in Moorea, and apparently for the first time in French Polynesia . Similarly, it has been collected only once in about three weeks of intensive sampling around Lizard Island.

As pointed out earlier (Anker & Jeng 2007), the synonymy of Arete ghardaqensis from the Red Sea (type locality: Hurghada, Egypt) and Athanas polynesia from the western Pacific (type locality: Tutuila, Samoa, herewith correcting error in Anker & Jeng 2007), proposed by Banner & Banner (1983) needs confirmation, especially by examining and sequencing fresh specimens from the type locality (Maldives), other parts of the Indian Ocean (especially the Red Sea), and the western Pacific.