New findings of rare or little-known alpheid shrimp genera (Crustacea, Decapoda) in Moorea, French Polynesia Author Anker, Arthur text Zootaxa 2010 2403 23 41 journal article 10.5281/zenodo.194125 6ae8ac53-d51b-4bdc-b3c9-856e0a3ef8a0 1175-5326 194125 Leptalpheus denticulatus Anker & Marin, 2009 Figure 10 Leptalpheus denticulatus Anker & Marin 2009 : 92 , figs. 1–6, 7a, b, 8. Material examined . French Polynesia , Society Islands. 1 ovigerous female (CL 8.90 mm ), FLMNH UF Arthropoda 16463, Moorea, lagoon near Nihimaru River estuary, near-shore sand flat with some rocks, algae, holothurians ( Holothuria atra ) from burrow, suction pump, depth: 0.5–1 m , coll. A. Anker, 17.XI.2008 [fcn BMOO-5519]; 1 female (CL 4.60 mm ), FLMNH UF Arthropoda 16528, Moorea, lagoon, between Papetoai and Hotel Intercontinental, near-shore sand flat with intense burrowing activity, silt and sand, mounds, holothurians ( Holothuria atra ), from burrow, suction pump, depth: 0.3–0.6 m , coll. A. Anker, 23.XI.2008 [fcn BMOO-5636]; ovigerous female (CL 5.40 mm ), FLMNH UF Arthropoda 16532, same collection data as for previous specimen, fcn 5641; 1 male (CL 4.90 mm ), 1 female (CL 7.00 mm), 1 juvenile (CL not determined), FLMNH UF Arthropoda 16526, same collection data as for previous specimens [ BMOO fcn 5634, 5635, 5633]. Description . See Anker & Marin (2009) . Colour pattern . Uniform pinkish, speckled with reddish chromatophores ( Fig. 10 ), more intense on antennular peduncles and tail fan ( Fig. 10 C, D), and in large individuals forming diffuse bands on abdomen ( Fig. 10 A, B; see also Anker & Marin 2009 , fig. 8); walking legs mostly colourless, major chela hyalinewhitish, with a few red chromatophores on palm ( Fig. 10 F). Type locality . Nhatrang Bay, Vietnam . Ecology . All Moorea specimens were collected on shallow near-shore sand flats, at depths ranging from 0.3 to 1 m , from burrows of unknown, presumably callianassid, hosts. Distribution . Nhatrang, Vietnam ; Panglao, the Philippines ; Viti Levu, Fiji ( Anker & Marin 2009 ); the present report extends its range eastwards to Moorea, French Polynesia . Remarks . Moorea is presently the only locality where L. denticulatus is known to occur sympatrically with L. pacificus . These two species are very closely related ( Anker & Marin 2009 ), but as mentioned above, L. denticulatus may be distinguished from L. pacificus by the presence of a small tooth on the mesial emargination of the uropodal diaeresis (cf. Fig. 9 D, 10E) and the presence of numerous red chromatophores that are evenly scattered over the body and together provide a uniform pinkish-reddish colour, more intense on the antennular peduncles ( Figs. 9 A–C, 10A–C). Interestingly, all specimens of L. denticulatus were collected from burrows near a small estuary or in very shallow silt-covered parts of the inshore lagoon, whereas L. pacificus was collected from burrows in fine white sand at some distance from the main coast, for instance near the Motu Tiahura – Moorea channel, where water is cleaner and more dynamic, indicating a possible ecological niche separation between these two species.