<htm> Camarões de águas continentais (Crustacea, Caridea) da Bacia do Atlântico oriental paranaense, com chave de identificação tabular </htm>

ABSTRACT. Temporal distribution of the hermit crab Clibanarius vittatus (Anomura, Diogenidae) from Paraná State coast, Brazil. A study on the temporal fluctuation of the population structure of the hermit crab Clibanarius vittatus (Bosc, 1802) was carried out at Baixio Mirim tideflat, Guaratuba Bay, Paraná State, southern Brazil (25°52'S, 48°36'W). Clibanarius vittatus is a species widely studied, but studies of population biology of these hermit crabs in different regions are scarce. Samplings were done in the intertidal zone, monthly, from April/2005 to March/2006. A total of 1187 hermit crabs were obtained, among which, 949 males, 22 intersexes, 204 nonovigerous females and 12 ovigerous females. The cephalothoracic shield length (CSL) was measured and grouped in 10 size classes. Males were distributed in 10 CSL classes while intersexes and females occurred only in six size classes. Males predominated in every month and in the whole population. All demographic categories were present all year round, except intersexes and ovigerous females. These were uncommon and occurred from late spring until autumn and in august/2005. The reproduction was considered seasonal-continuous, with higher intensity in the warmer months. The observed sex ratio in this population, that was different from other ones, corroborates the theory of migration for this species. The present research constitutes the first record of reproductive period of C. vittatus population occurring in warm subtropical shallow waters. KEYWORDS.Intertidal hermit crabs, reproductive period, intersexes, sex ratio, size classes. RESUMO. Um estudo sobre a flutuação temporal da estrutura populacional do ermitão PALAVRAS-CHAVE.Ermitões da zona entremarés, período reprodutivo, intersexos, razão de sexos, classes de tamanho.

A study on morphometric relationships between the hermit crab Isocheles sawayai and its shell in a population from Paraná-Santa Catarina States coast was carried out. Hermit crabs from the by-catch of shrimp fishing (4-15m depth) were collected. Cephalothoracic shield length (CL) and width (CW) from hermit crabs and total length (SL), aperture length (AL) and weight (SW) from shells were taken. A total of 266 hermit crabs occupying eight species of shell -Buccinanops lamarckii, Dorsanum moniliferum, Oliva reticularis, Olivancillaria steeriae, O. urceus, Polinices hepaticus, Semicassis granulatum and Stramonita haemastoma -were obtained. Males (N = 189) that dominated strongly (1M : 0.4 F) occupied eight shell species, while females (N = 76) occupied only six. There was only one intersex individual that occupied a Stramonita shell. Contrarily to intertidal populations, O. urceus was the most frequently occupied shell by males (57.14%) and females (62.33%) in this studied area. Due to the smaller size of females (mean CL 5.19±0.84mm), these ones occupied shells of a smaller size than males (mean CL 6.49±1.14mm). The highest O. urceus shell frequency of occupation is connected to the hermit crab´s life style: it is a filter feeding species and its shell remains totally buried in the sandy substratum having only its cephalothoracic appendages free. The heavy shell of this gastropod (highest SW/SL) favors the stability in strong current water conditions, as it functions as an anchorage for this semi-buried hermit crab.

A characterization of the occupied shells by the hermit crab Clibanarius vittatus was carried out. Hermit crabs were collected in the intertidal zone, during the low spring tide monthly from April 2005 to March 2006. They were sexed and their cephalothoracic shield length (CL) was measured. Shells were identified, dried, weighed and the aperture length (AL) and width (AW) were measured. 1187 crabs were collected (949 males, 216 females and 22 intersexes), which occupied 12 species of gastropod shells. Stramonita haemastoma, Olivancillaria urceus and Dorsanum moniliferum made up 96.55% of the total shell species. Male hermit crabs attained significantly larger sizes than females; therefore, males occupied a wider spectrum of shells in size and weight. A stronger correlation ratio was obtained between CL and AW of S. haemastoma. Last whorl with a rounded shape and a spacious inner area is a common feature of all shell species most frequently occupied by this hermit crab where it occurs. The successful establishment of C. vittatus at Baixio Mirim is mainly due to the appropriately shaped and wide range of size of S. haemastoma shells that were most often occupied by the hermit crabs of the studied population.