Australocarcinus Davie, 1988

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 136-140

Genus Australocarcinus Davie, 1988

Australocarcinus Davie, 1988: 260 ; 2002: 504 [in list].— Davie & Guinot 1996: 278.— Jamieson & Guinot 1996: 289, 294 [sperm ultrastructure].—Ng et al. 2008: 76 [in list].— Guinot et al. 2013: 42, 113.— De Grave et al. 2009: 33 [in list].

Type species. Australocarcinus riparius Davie, 1988 (by original designation; gender masculine) Other species included:

Australocarcinus kanaka Davie & Guinot, 1996

Australocarcinus palauensis Davie & Guinot, 1996

Diagnosis. Carapace subquadrate or subrectangular, front bilobed, with shallow median cleft; anterolateral margins arcuate, with crest with or without teeth. Epistome compressed, posterior margin with median lobe with fissure, circular lateral margins without fissures. Eye peduncle filling, short, mobile; cornea normal, pigmented. Third maxillipeds leaving gap when closed; merus quadrate, auricular anteroexternal angle, ischium quadrate, slightly longer than merus. Chelipeds subequal in length, slightly dissimilar in both sexes; cutting margins of both chelae with small teeth in both sexes; fingers of minor chela subcircular in cross-section, not laterally flattened, gently tapering to tip, shear-like, cutting margins with few low teeth; ventral surface of cheliped merus bordered by large tubercles; anterior margin of dorsal surface of propodi with large tooth, Proportionally long or short ambulatory legs, P5 dactylus straight. Meri of ambulatory legs unarmed. Fused thoracic sternites 1, 2 broadly triangular, short; fused sternites 3, 4 relatively broad. Male pleon with lateral margins of somite 6, fused somites 3‒5 nearly straight; postero-lateral regions only slightly swollen; telson proportionally short. Sterno-pleonal cavity of male deep, pressbutton for pleonal holding as small, short tubercle posterior to thoracic sternal suture 4/5 near edge of sternopleonal cavity. Male thoracic sternite 8 proportionally short, rectangular; “supplementary plate” conspicuously narrow, short, rectangular. “Supplementary plate” proportionally narrow, long. G1 stout, distal part with tapering tip, covered with short spinules. G2 longer than G1, basal segment curved; distal segment slightly longer than basal segment, apex with lateral pointed tip. Somites of female pleon with slightly convex lateral margins; telson proportionally long. Sterno-pleonal cavity of female moderately deep, with conspicuously large vulvae close or far apart from each other, covering full extent of thoracic sternite 5, round, thin, raised lip on outer margin, soft membrane across, leaving proportionally small opening.

Remarks. The G2 of A. riparius and A. kanaka (unknown in A. palauensis ) is clearly longer that the G1 ( Fig. 98 B, D; Davie & Guinot 1996: fig. 4A). Davie & Guinot (1996: 279) stated that the “G2 as long as first” in the diagnosis of Australocarcinus .

Distribution. Indo-West Pacific region: Palau, Australia (Queensland), and New Caledonia.

Figures

FIGURE 98. Gonopods of species of Australocarcinus and Trogloplax. A, B, Australocarcinus riparius, Australia: holotype male (after Davie 1988: fig. 1 A, B); C, D, Australocarcinus kanaka, New Caledonia: holotype male 9.5 × 11.1 mm (after Davie & Guinot 1996: fig. 4); E, F, Trogloplax joliveti, New Britain: paratype male 20.0 × 27.0 mm (MNHN-IU- 2014 - 10458) (after Guinot 1986: pl. 2 F, G); G ‒ J, Trogloplax joliveti, New Britain: male 15.7 × 18.6 mm (ZRC 2015.294). Scales: G, J = 1.0 mm; H, I = 0.5 mm.