Limnopilos Chuang & Ng, 1991

Naruse, Tohru & Ng, Peter K. L., 2007, On the taxonomy of the genus Hymenicoides Kemp, 1917 (Crustacea: Decapoda: Brachyura: Hymenosomatidae), with resurrection of Limnopilos Chuang & Ng, 1991, and descriptions of two new species, Zootaxa 1621, pp. 17-31 : 26

Limnopilos Chuang & Ng, 1991

Limnopilos Chuang & Ng, 1991: 363 .

Hymenicoides— Ng & Chuang, 1996: 50 (part); Guinot & Richer de Forges, 1997: 460 (part).

Type species. Limnopilos naiyanetri Chuang & Ng, 1991 , by original designation and monotypy; gender of genus masculine.

Diagnosis. Carapace circular, pilose, dorsal surface concave; grooves distinct; rostrum absent or very weak; antenna with proximal portion of basal article posterior to inner section of proximal portion of eye; eyes, antennae, antennules visible dorsally; third maxillipeds narrow, not covering more than three-quarters of mouth field when closed, merus rectangular, dactylus styliform, approximately twice length of propodus; male chelae relatively stout, outer surface evenly convex, partially covered by dense setae, without tubercle. Female vulva placed on imaginary line joining inner ends of sutures between sternites 5, 6 on medial fused plate of thoracic sternum, vulva with basal mount. Male abdomen-pleotelson 6 segmented, pleotelson slightly trilobed, inner surface thickened distally, forming socket for sternal button ( Fig. 1 c, d). G1 stout, bent outwards medially; distal part with distal inner processes, tuberculate distal outer angle. Female abdomen-pleotelson with six distinctly demarcated segments, boundary between first and second ( L. sumatranus ) or between second and third segments ( L. naiyanetri ) movable; long, biramous pleopods on second to fifth segments, developed from distal outer end of inner surface of each segment.

Remarks. Several characters clearly distinguish Limnopilos from Hymenicoides (see Remarks for Hymenicoides above). In addition to L. naiyanetri , the type species, H. microrhynchus Ng, 1995 , and L. sumatranus new species, all possess the diagnostic characters of the genus and are therefore transferred to Limnopilos .

In the case of L. microrhynchus , only male specimens are known thus far, and the female characters diagnosed above are therefore not known for this species.

Figures

FIGURE 1. Male abdominal cavity and pleotelson of Hymenicoides robertsi new species, and Limnopilos species. a, b, Hymenicoides robertsi new species (paratype, ZRC 2007.0109, 5.0 × 6.2 mm); c, d, L. naiyanetri Chuang & Ng, 1991 (ZRC 1991.6521 – 6555, 4.9 × 5.3 mm); e, f, L. sumatranus new species (paratype, ZRC 2007.0114, 5.0 × 5.9 mm). a, c, e, male abdominal cavity with sternal button (sb) and G 1; b, d, f, inner surface of male pleotelson.