Dynomenidae and Dromiidae (Decapoda, Brachyura) from Guam, Philippine Islands, Tonga and Samoa Author Mclay, Colin L. Zoology Department, Canterbury University, Christchurch, PB 4800 (New Zealand) c. mclay @ zool. canterbury. ac. nz. text Zoosystema 2001 23 4 807 856 journal article 6377 10.5281/zenodo.4689208 72669070-3bd6-41be-bd47-f386c83d0927 1638-9387 4689208 Genus Sphaerodromia Alcock, 1899 DIAGNOSIS. — Carapace sub-globose, as wide or wider than long, surface gradually rounded, tomentose. Front broadly triangular, grooved in midline, rostrum not developed, continuous with supraorbital margin. Distomedial corner of second antennal segment not produced. Coxae of third maxillipeds closely approximated and inserted under tip of sternum. Female sternal sutures 7/8 end wide apart behind genital openings. Cheliped with an epipod and well-developed podobranch, first two pairs of legs also have epipods, with or without podobranchs. Chelipeds longer and stouter than first two pairs of legs, which are not nodose. Usually a small propodal spine on inferior margin overlapping with dactyli of first two pairs of legs. Last two pairs of legs reduced, similar in size, only last pair subdorsal. Three to five propodal spines opposing dactyli, no spines on outer propodal margin, but two to four small spines on inner margin of dactyli. Abdomen of six free segments. Telson rounded, longer than wide in male, wider than long in female. Uropod plates well-developed, visible externally and occluding up to approximately half the sub-terminal abdominal segment from the lateral margins. Abdominal locking mechanism consists of denticulate ridges on coxae of first two legs against lateral margins of telson and last two segments, uropods not used. First male gonopod with a small rounded terminal plate, second gonopod simple, needle-like, with longitudinal row of sub-terminal spines, and an exopod on the basis. Vestigial pleopods present on male segments three to five (modified after McLay 1993 ).