Richalpheus palmeri Anker & Jeng, 2006

Figures 7, 8

Richalpheus palmeri Anker & Jeng 2006: 381, figs. 1–6.

Material examined. French Polynesia, Society Islands. 1 female (CL 3.35 mm), FLMNH UF Arthropoda 16524, Moorea, lagoon, between Papetoai and Hotel Intercontinental, sand flat with mounds and some rubble, nearby coral heads, numerous Holothuria atra Jaeger, 1833, from burrow, suction pump, depth: 0.5–1 m, coll. A. Anker, 23.XI.2008 [fcn BMOO-5632].

Description. See Anker & Jeng (2006).

Colour pattern. Uniformly hyaline-white, semitransparent, tiny red chromatophores hardly visible on abdomen, along branchiostegial margin of carapace, on uropods and telson, and on antennular peduncle; ovaries visible through semi-translucent carapace, extending from carapace into first abdominal somites, pale yellow (Figs. 7, 8).

Type locality. Panglao, the Philippines.

Ecology. The Moorea specimen was collected in the lagoon, on a shallow sand flat about 0.5–1 m depth at low tide, with isolated coral heads and numerous sea cucumbers (Holothuria atra), from burrows of unknown hosts. Similarly, the holotype was collected from a burrow on a sand flat, in slightly deeper water (3–4 m). Some Callianassidae, in particular larger species of Glypturus Stimpson, 1866 and Neocallichirus Sakai, 1988 are the most likely candidates for being the actual burrowing host(s) of R. palmeri (see also Anker & Jeng 2006).

Distribution. Previously known only from the holotype from Panglao, the Philippines (Anker & Jeng 2006); herewith recorded for the first time from Moorea, French Polynesia, representing a considerable range extension from the “Coral Triangle” area into the central-western Pacific Ocean.

Remarks. Richalpheus palmeri is the type species of the recently established genus Richalpheus. The Moorea specimen agrees in most aspects with the holotype; the only noticeable differences are the distinctly more concave posterior margin of the uropodal exopod (Fig. 8 B, C, cf. Anker & Jeng 2006, fig. 2j) and the slightly shorter second segment of the antennular peduncle (Fig. 5 A, cf. Anker & Jeng 2006, fig. 2a). Considering these relatively minor differences and the large distance between the Philippines and French Polynesia, more specimens from both localities (and from other areas) and DNA comparisons are desirable to confirm the identity of specimens collected far outside the type locality. A second species of Richalpheus, R. dahabensis Anker & Dworschak, 2007, was recently described from the Red Sea, also based on a single specimen, but this species can be separated from R. palmeri by the absence of a fossa/tooth system on the major cheliped fingers (Anker & Dworschak 2007).