Aphanodactylidae Ahyong

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2016, On the genera Selwynia Borradaile, 1903, and Gandoa Kammerer, 2006, with descriptions of two new species from Papua New Guinea and French Polynesia (Crustacea: Decapoda: Brachyura: Aphanodactylidae), Zootaxa 4092 (3), pp. 339-370 : 340

Aphanodactylidae Ahyong & Ng, 2009

Aphanodactylidae Ahyong & Ng, 2009: 34. Gustavini Števčić, 2011: 129.

Diagnosis. Carapace strongly sexually dimorphic (when both sexes known); female carapace transversely ovate to rectangular; male carapace narrower than that of female, ovate to subquadrate; surface glabrous or finely setose; smooth or punctate; regions poorly defined. Front deflected ventrally, faintly sinuous to bilobed in dorsal view. Orbital margins entire, well defined, infraorbital margin terminating mesially as angular tooth or rounded corner. Antennules folding transversely or obliquely. Antennae not excluded from orbit. Cornea pigmented. Third maxilliped ischium usually longer than merus, subquadrate or triangular; merus subquadrate to round; palp articulating at distolateral margin of merus, segments articulating end-to-end, decreasing in size distally; exopod with distinct flagellum. Chelipeds equal; segments unarmed; surfaces smooth, finely to sparsely setose. Ambulatory legs of varying lengths, usually stout; P3 longest, P5 shortest, dorsally inserted compared to other pereopods; P3–4 merus usually with row of spines or teeth on flexor margin; propodus distoflexor angle unarmed, or with 1 or more spines opposing dactylus; dactylus short, claw-like, apices corneous. Female gonopore (vulva) large, on sternite 6, between suture 5/6 and 6/7. Male gonopore (genital papilla) emerging near anterior margin of sternite 8, distinctly mesial to P5 coxa. Adult abdomen ovate, with all somites and telson distinct, mobile. Male abdomen narrowly triangular or linguiform, with somites and telson mobile or with somites 4–6 fused. (Modified from Ahyong & Ng 2009: 34).

Remarks. Members of this family have a substantial diversity of carapace and ambulatory leg form (see Ahyong & Ng 2009; Naruse & Maenosono 2012), but as far as known, all live with polychaete worms, and share the common feature of possessing a very short ambulatory dactylus. The tribe Gustavini Števčić, 2011, established for the monotypic Gustavus Ahyong & Ng, 2009, was shown to be a junior subjective synonym of Aphanodactylidae (Ng & Clark 2014).