Singhaplax platypoda, Castro, 2007

Castro, Peter, 2007, A reappraisal of the family Goneplacidae MacLeay, 1838 (Crustacea, Decapoda, Brachyura) and revision of the subfamily Goneplacinae, with the description of 10 new genera and 18 new species, Zoosystema 29 (4), pp. 609-774 : 716-718

Singhaplax platypoda n. sp.

( Figs 36 ; 37 )

TYPE MATERIAL. — KARUBAR, stn DW 22, ♂ holotype, cl 2.8 mm, cw 5.1 mm ( MNHN-B 29215). — MUS- ORSTOM 7, stn DW 495, pre-adult ♀ paratype, cl 3.3 mm, cw 6.0 mm ( MNHN-B 30068).

TYPE LOCALITY. — Indonesia, Kai Islands, 05°22’S, 133°01’E, 85- 124 m.

MATERIAL EXAMINED. — Indonesia. Kai Is, KARUBAR, stn DW 22, 05°22’S, 133°01’E, 124- 85 m, 25.X.1991, ♂ holotype, cl 2.8 mm, cw 5.1 mm ( MNHN-B 29215). Futuna Island. MUSORSTOM 7, stn DW 495, 14°19’S, 178°04’W, 180-210 m, 10.V.1992, pre-adult ♀ paratype, cl 3.3 mm, cw 6.0 mm ( MNHN-B 30068).

ETYMOLOGY. — From platys, Greek for “broad” or “wide,” and podus, Greek for “foot,” in reference to the flat, broad propodus and dactylus of the P5 characteristic of the species.

DISTRIBUTION. — Indonesia (Kai Is) and Futuna I. (southwestern Pacific Ocean). Depth: 85- 210 m.

DESCRIPTION

Carapace ( Figs 36A ; 37 ) transversely rectangular, much wider than long (1.8 as wide as long in holotype). Carapace convex, without clear indication of regions. Front straight. Notch between front, inner edge of supraorbital border absent. Supraorbital borders broad, conspicuously sinuous, smooth, with long simple setae. Suborbital borders conspicuously sinuous, slightly granular, inner tooth absent. Long, slender, acute tooth on outer orbital angle; tooth medially placed on carapace. Lateral borders beyond outer orbital teeth slightly curved, slight swelling immediately below teeth in pre-adult female paratype, no anterolateral teeth.

Subhepatic, pterygostomial regions, with low, round tubercles.

Eye peduncles ( Figs 36A ; 37 ) long (equal to front width), cornea elongated, spherical distal margin, not reniform.

Chelipeds (P1) of pre-adult female paratype (missing in male holotype) nearly equal ( Fig. 37 ); fingers slender, slightly curved, slightly shorter than propodus, with blunt teeth; no dark colour on fingers; inner (ventral) margin of propodus smooth. Broad tooth on inner (ventral), proximal margin of carpus; outer (dorsal) margin of merus with low tubercles, long simple setae. P2-P4 ( Fig. 37 ) long, slender, unarmed, varying number of long simple setae; dactyli long, slender, each with 2 carinae along each side; P5 ( Fig. 37 ) propodus, dactylus broad, dorso-ventrally flattened, wide, without carina, bordered by many long, simple setae; dactylus ending in acute tooth; length of P5 merus 0.7 cl.

Male abdomen ( Fig. 36A ) wide, with 6 freelymovable somites plus telson; telson slightly longer than wide. Somite 3 covers space between P5 coxae; somite 2 only slightly narrower than somite 3, leaving small portion of thoracic sternite 8 visible. G1 ( Fig. 36B ) long, slender, tubular in appearance, slightly wider basal part, straight distal part; slender, truncated tip. G2 ( Fig. 36C ) slender, long, slightly longer than G1, curved flagellum longer than proximal part (peduncle), pointed tip.

Abdomen of pre-adult female paratype narrow, outer margin of thoracic sternites visible. Vulva of pre-adult paratype barely visible, near edge of suture 5/6.

Castro P.

REMARKS

The species is being described as new, even if only two specimens are available, on account of the flat, broad P5 dactylus ( Fig. 37 ), a unique feature in Singhaplax and related genera, with the exception of Goneplacoides marivenae n. comb. ( Komatsu & Takeda, 2003). Both specimens are small. The female is clearly a pre-adult, but the G1 and G2 of the male appear fully formed. The shape of the male telson, like that of S. dichotoma n. sp., departs from that of other species of Singhaplax , except S. dichotoma n. sp. and S. styrax n. sp., by being slightly longer than wide.The outer orbital teeth are medially placed on the carapace, in contrast to S. styrax n. sp., where they are more anteriorly placed on the carapace.

Figures

FIG. 36. — Singhaplax platypoda n. sp., ♂ holotype, cl 2.8 mm,cw 5.1 mm,Kai Is, Indonesia,KARUBAR,stn DW 22 (MNHN-B 29215): A, abdomen; B, right G1, ventral view; C, right G2, ventral view. Scale bars: A, 2 mm; B, C, 1 mm.

FIG. 37. — Singhaplax platypoda n. sp.,pre-adult ♀ paratype,cl 3.3 mm,cw 6.0 mm,Futuna I., MUSORSTOM 7, stn DW 495 (MNHN-B 30068).