(Fig. 86)

Ulloaia perpusillia Glassell 1938: 434, pl. 33, fig. 3; Haig 1960: 230, fig. 11, pl. 37, fig. 2; Haig 1962: 191; Gore & Abele 1976: 26.

Material examined. Panama [Pacific]: 1 male, cl 2.1, cw 1.7 (MZUSP 40073), Isla Venao, 08°52’48.6”N, 79°35’36.9”W, no further details, leg. L.R.L. Simone, 01.02.2006. Extra-limital material. Costa Rica [Pacific]: 1?male, cl cw indet. (MZUCR 5098-03), Area de Conservación Guanacaste, Golfo de Santa Elena, Bajo Rajada, depth 21 m, among loose rocks, leg. R. Vargas, G. Ampie & Y. Vega, 07.06.2016 [examined and identified by R. Vargas Castillo].

Previous records from Panama. Gore & Abele (1976).

Distribution. East Pacific: Mexico, Costa Rica and Panama (Isla Venao, Las Perlas Is.) (Haig 1960, 1962; Gore & Abele 1976; present study).

Ecology. Intertidal and subtidal, more common in the subtidal, known depth range: 0–21 m; among rocks, sand, gorgonians, sponges and bryozoans (Glassell 1938; Haig 1960, 1962); the specimen from Taboga I. was “washed from sponge”; the one from Contadora I. (Las Perlas Is.) was collected on “stones, sand, 8–10 fathoms [14–17 m]” (Haig 1962).

Remarks. Ulloaia perpusillia is a rarely collected porcelain crab, which is probably due to its cryptic life style (possibly associated with sponges) and very small size. Haig (1962) noted that the female from Taboga I. was only 2.1 mm long, but fully mature; a previously reported female was only slightly larger, at cl 2.9 mm. The specimen from Venao I. is a male with cl 2.1 mm and is thus similar in size to other specimens of U. perpusillia. Haig (1962) also observed that in the Taboga I. specimen, “the front is less deflexed and partially visible in dorsal view”, whereas in the juvenile specimen from Contadora I. at cl 1.4 mm, “the front is much less sharply deflexed and the rostral process is fully visible in dorsal view.” This observation could explain the difference seen at first glance between the front of Glassell’s male holotype (Fig. 86A), in which the front is deflexed and not visible in dorsal view, just like in the male specimen from Venao I., and the specimen from Guanacaste, Costa Rica (Fig. 86B), in which the rostral process is well visible in anterodorsal view.