Shell selection by the hermit crab Paguristes tortugae Schmitt, 1933 from Anchieta Island (Brazil) was analyzed using the six most frequently occupied shell species in the field and taking into account the sexual condition of the individuals, the shell size and the shell species. The experiments were conducted under laboratory conditions and the shell species preference was estimated on the basis of the frequency that each species was chosen by the individuals. The preferred shell species and size were determined by regression analysis. The highest correlation coefficients were obtained for the relations between the hermit dimensions and shell dry weight. The ovigerous females preferred shells with larger internal volume: Leucozonia nassa (Gmelin, 1791) and Cerithium atratum (Born, 1778). In the experiment of shell size, males preferred heavier shells whereas females selected the shape characteristics of the shell, such as the aperture and the internal volume, which are probably related to the growth and offspring guarantee, respectively. In general, and independent of sex condition, P. tortugae showed significant selection among all shells utilized. The results suggest that shell selection by P. tortugae involves sexual and reproductive condition preferences.

Este trabalho caracterizou a composição dos braquiúros em Schizoporella unicornis. As amostras foram coletadas na Praia do Itaguá, Ubatuba (SP), em intervalos de três meses, durante as estações climáticas de Janeiro a Dezembro/1995. As colônias de briozoários foram obtidas por mergulho livre, coletadas pela manhã. Um total de 323 espécimes foram coletados dentro de quatro famílias (Xanthidae, Portunidae, Majidae e Grapsidae). Pachygrapsus transversus, Hexapanopeus schimitti e Menippe nodifrons ocorreram em todas as estações. O maior e o menor número de indivíduos foram registrados na primavera e no outono, respectivamente. Xanthidae exibiu maior densidade no verão, outono e primavera, enquanto Grapsidae foi no inverno. Registrou-se a ocorrência de Charibdis hellerii, espécie originária do Indo-Pacífico. A diversidade de espécies obtida, juntamente com o acentuado número de indivíduos imaturos e fêmeas ovígeras, constituem indícios de que colônias de Schizoporella constituem um local de reprodução e desenvolvimento para estes crustáceos

This work characterizes the composition of Brachyura from Schizoporella unicornis. The samples were collected in 1995 at Itaguá Beach, Ubatuba (SP), at three month intervals, during all seasons from January to December. The Bryozoa colonies were obtained by snorkeling at a depth of five meters in daylight. A total of 323 specimens were collected from four families (Xanthidae, Portunidae, Majidae and Grapsidae). Pachygrapsus transversus, Hexapanopeus schimitti, and Menippe nodifrons occurred in all seasons. The highest and lowest number of individuals occurred during the spring and autumn, respectively. Xanthidae exhibited the highest density during the summer, autumn, and spring, while Grapsidae exhibited the highest density in winter. It was noted the presence of Charibdis hellerii, an portunid from Indo-Pacific ocean. The diversity of species obtained, in addition to an accentuated number of immature and ovigerous females specimens, suggested that Schizoporella colonies were a place of reproduction and development.