Arcotheres Manning, 1993

Campos, Ernesto, 2001, A new crab species of the genus Arcotheres Manning, 1993, from Thailand (Crustacea, Brachyura, Pinnotheridae), Zoosystema 23 (3), pp. 493-497 : 494

Genus Arcotheres Manning, 1993

TYPE SPECIES. — Pinnotheres palaensis Bürger, 1895 , by designation by Rathbun (1918: 62).

HOSTS. — Mollusca, Bivalvia.

DISTRIBUTION. — Indo-West Pacific.

DIAGNOSIS. — (After Campos & Manning in press). Carapace subhexagonal, anterolateral margin acute, posterior margin concave. Mxp3 with ischium and merus indistinguishably fused; exopod with 3-segmented flagellum; palp 3-segmented; propodus longer than carpus; digitiform dactylus inserted medially on ventral margin of propodus, may extend or slightly overreaching apex of propodus. Wl3 asymmetrical in length, either left or right is longer. Dactyli of wl dissimilar, those of wl3-4 longer than wl1-2. Abdomen of six somites and telson well-separated in both sexes.

REMARKS

A morphological analysis of Pinnotheres spinidactylus Gordon, 1936 (Siglap, Singapore; Moreton Bay, Queensland, Australia), P. tivelae Gordon, 1936 ( Muscat, Arabia) and P. alcocki Rathbun, 1910 (Mergui archipelago, Philippine Islands, and Indonesia) (see Gordon 1936) led me to believe that these species should be exclud- ed from Pinnotheres Bosc, 1802 and included within Arcotheres instead. The features of these species agree well with the above diagnosis of Arcotheres . In particular, they have a subhexagonal carapace, acute anterolateral margins, wl3 asymmetrical and longer than the others, and the dactyli of wl dissimilar, those of wl3-4 being longer than those of wl1-2. The genus Pinnotheres sensu stricto in contrast, has a suborbicular carapace and wl2 asymmetrical and longer than the others ( Manning 1993).