Leptalpheus pacificus Banner & Banner, 1974

Anker, Arthur, 2010, New findings of rare or little-known alpheid shrimp genera (Crustacea, Decapoda) in Moorea, French Polynesia, Zootaxa 2403, pp. 23-41 : 36-38

Leptalpheus pacificus Banner & Banner, 1974

Fig. 9

Leptalpheus pacificus Banner & Banner 1974: 424 , fig. 1; Anker & Marin 2009: 92, 100, fig. 7c–h. (?) Leptalpheus pacificus – Banner & Banner 1983: 82, 121 [see Anker & Marin 2009]

Material examined. French Polynesia , Society Islands. 1 male (CL 7.50 mm), FLMNH UF Arthropoda 16489, Moorea, Motu Tiahura, 17.4884˚ S, 149.9134˚ W, near-shore sand flat with some rubble, further offshore sea grass, from burrow, suction pump, depth: 0.2 m, coll. A. Anker, 18.XI.2008 [fcn BMOO-5555]; 1 ovigerous female (CL 8.10 mm), FLMNH UF Arthropoda 16503, same collection data as for previous specimen [fcn BMOO-5569]; 1 ovigerous female (CL 7.90 mm), OUMNH.ZC.2010-01-003, Moorea, Motu Tiahura, near channel between two islands, 17.4884˚ S, 149.9134˚ W, shallow sand flat, from burrow, suction pump, depth: 0.5–1 m, coll. A. Anker, V. Liao, 10.XI.2009.

Additional specimen examined by J. Poupin: 1 male (CL ~6.00 mm), MNHN, Moorea, Tipanier sandy beach, coll. J. Poupin, XII.2006.

Description. See Banner & Banner (1974).

Colour pattern. Uniform hyaline-whitish, with yellowish tinge, especially on antennules and tail fan ( Fig. 9 ).

Type locality. Pearl Harbor, Oahu, Hawaii.

Ecology. The Moorea specimen was collected on a shallow sand flat, near the shore, from a burrow of an unknown, presumably callianassid host.

Distribution. Previously known only from Oahu and Maui in Hawaii ( Banner & Banner 1974; Anker & Marin 2009) and Madagascar ( Banner & Banner 1983, record questionable); now recorded for the first time from Moorea, French Polynesia .

Remarks. With the present record from Moorea, L. pacificus is eliminated from the list of the Hawaiian marine endemics. The main feature distinguishing L. pacificus from the closely related L. denticulatus (see below) is the blunt, somewhat rounded angle of the mesial emargination of the uropodal diaeresis ( Fig. 9 D); in L. denticulatus , this angle is protruding in the form of a small tooth (cf. Fig. 10 E). Another, previously unknown difference between these two species lies in the colour pattern: L. pacificus is overall whiteyellowish ( Fig. 9 ), whereas L. denticulatus is pinkish or reddish ( Fig. 10 ; see also Anker & Marin 2009, fig. 8).

Figures

FIGURE 9. Leptalpheus pacificus Banner & Banner, 1974, male (CL 7.50 mm) from Moorea, FLMNH UF Arthropoda 16489; A, dorsal view; B, lateral view; C, frontal region, dorsal view; D, uropodal exopod, dorsal view; E, major cheliped in situ, lateral view; E, same, detail of fingers.

FIGURE 10. Leptalpheus denticulatus Anker & Marin, 2009, three specimens from Moorea: A-D, ovigerous female (CL 8.90 mm), FLMNH UF Arthropoda 16463; E, ovigerous female (CL 5.40 mm), FLMNH UF Arthropoda 16532; F, female (CL 4.60 mm), FLMNH UF Arthropoda 16528; A, dorsal view; B, lateral view; C, frontal region, dorsal view; D, major chela, detail of fingers; E, tail fan, dorsal view; F, major cheliped in situ, lateral view.