Richalpheus palmeri Anker & Jeng, 2006

Anker, Arthur, 2010, New findings of rare or little-known alpheid shrimp genera (Crustacea, Decapoda) in Moorea, French Polynesia, Zootaxa 2403, pp. 23-41 : 34

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).

Figures

FIGURE 5. Prionalpheus triarticulatus Banner & Banner, 1960, ovigerous female (CL 4.05 mm) from Moorea, OUMNH. ZC. 2010 - 01 - 002 (A – C) and Prionalpheus cf. brachytomeus Banner & Banner, 1971, possibly male (CL 2.55 mm) from Moorea, FLMNH UF Arthropoda 16447 (D – F): A, D, rostral region, dorsal view; B, E, second pereiopod, carpus and chela; C, F, third pereiopod, distal propodus and dactylus. Scale bars = 0.5 mm.

FIGURE 7. Richalpheus palmeri Anker & Jeng, 2006, female (CL 3.35 mm) from Moorea, FLMNH UF Arthropoda 16524; A, dorsal view; B, lateral view.

FIGURE 8. Richalpheus palmeri Anker & Jeng, 2006, female (CL 3.35 mm) from Moorea, FLMNH UF Arthropoda 16524; A, frontal region, dorsal view; B, tail fan, lateral view; C, same, dorsal view; D, major cheliped in situ, lateral view; E, same, detail of fingers and chela of second pereiopod.