Microgoneplax cope, 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 : 728

Microgoneplax cope n. sp.

( Fig. 43 )

TYPE MATERIAL. — MUSORSTOM 7, stn DW 513, ♂ holotype, cl 4.4 mm, cw 8.4 mm ( MNHN-B 30063).

TYPE LOCALITY. — Southwestern Pacific Ocean, Futuna I., 14°13’S, 178°11’W, 260- 300 m.

MATERIAL EXAMINED. — Futuna Island. MUSORSTOM 7, stn DW 513, 14°13’S, 178°11’W, 260-300 m, 12.V.1992, ♂ holotype, cl 4.4 mm, cw 8.4 mm ( MNHN-B 30063).

ETYMOLOGY. — From kope, noun in apposition, Greek for “oar” or “paddle”, in reference to the expanded, paddle-like G1 diagnostic of the species.

DISTRIBUTION. — Known only from Futuna I., southwestern Pacific Ocean. Depth: 260- 300 m.

DESCRIPTION

Carapace ( Fig. 43A ) transversely rectangular, much wider than long (1.9 as wide as long in holotype). Carapace convex, without clear indication of regions. Front slightly convex, almost straight. Slight notch between front, inner edge of supraorbital border. Supraorbital borders broad, conspicuously sinuous, smooth, with long simple setae. Suborbital borders conspicuously sinuous, finely granular, each with large, wide, rectangular inner tooth not visible dorsally. Long, slender, acute tooth on outer orbital angle. Lateral borders beyond outer orbital teeth slightly convex, no anterolateral teeth.

Subhepatic, pterygostomial regions, with low, round tubercles.

Eye peduncles ( Fig. 43A ) long (0.7 front width), cornea elongated, spherical distal margin, not reniform.

Chelipeds (P1) unequal in male holotype (female unknown); fingers slender, slightly curved, shovel-like, slightly shorter than propodus, with blunt teeth; no dark colour on fingers; inner (ventral) margin of propodus with round tubercles. Broad tooth on inner (ventral), proximal margin of carpus; outer (dorsal) margin of merus with low, tooth-like tubercles, long simple setae. Ambulatory legs (P2-P5) long, slender, unarmed, varying number of long simple setae; dactyli long, slender, each with 2 carinae along each side; length of P5 merus 0.8 cl.

Male abdomen narrowly triangular, with 6 freelymovable somites plus telson; telson longer than wide. Somite 3 covers most space between P5 coxae; somite 2 only slightly narrower than somite 3, leaving large portion of thoracic sternite 8 visible. G1 ( Fig. 43B ) long, slender, slightly wider basal part with long plumose setae, thick denticles along inner margin of distal part; slender, pointed tip. G2 ( Fig. 43C ) slender, short, less than half G1 length; slightly curved, thick flagellum about same length of proximal part (peduncle), much expanded, broad tip with terminal spinule.

Female unknown.

REMARKS

The species is being described from only one male specimen from Futuna I., southwestern Pacific Ocean. Its G1 ( Fig. 43B ), much broadened in the median portion and thus paddle-shaped and its median portion bordered by thick denticles, is unique among the species of Microgoneplax n. gen. The G2 ( Fig. 43C ) has only one terminal spicule.

Figures

FIG. 43. — Microgoneplax cope n.sp., ♂ holotype,cl 4.4 mm,cw 8.4 mm,Futuna I., South Pacific,MUSORSTOM 7, stn DW 513 (MNHN-B 30063): A, dorsal surface of the carapace; B, left G1, ventral view; C, left G2, ventral view. Scale bars: A, 5 mm; B, C, 1 mm.