O presente estudo teve como objetivo caracterizar a ocupação de conchas por ermitões no litoral da cidade de Rio Grande, Estado do Rio Grande do Sul. Os animais foram amostrados em 14 radiais em Rio Grande, entre 12 e 50 metros de profundidade. Cada ermitão e sua respectiva concha foram identificados, pesados e medidos. Um total de 408 animais foi capturado, pertencentes às famílias Diogenidae e Paguridae; as duas espécies mais abundantes foram Dardanus insignis (de Saussure, 1858) e Loxopagurus loxochelis (Moreira, 1901). Os ermitões ocuparam conchas de 13 espécies de gastrópodes, principalmente de Buccinanops lamarckii (Kiener, 1834) e B. gradatum (Deshayes, 1844). Dardanus insignis utilizou 12 das 13 espécies de moluscos registradas; Loxopagurus loxochelis utilizou nove. De um modo geral, o padrão de ocupação de conchas apresenta uma correlação entre o tamanho do ermitão e o tamanho da concha; no caso das duas espécies de ermitões mais abundantes, a maior correlação foi entre peso/tamanho do animal e o tamanho da abertura da concha, evidenciando, que a ocupação de conchas se dá não apenas pela disponibilidade local das mesmas, mas também pelas relações entre as variáveis dos ermitões e das conchas de gastrópodes.

The present study aimed to characterize the shell occupation by hermit crabs at the Rio Grande city, state of Rio Grande do Sul. Animals were sampled at 14 radials in Rio Grande, between 12 and 50 meters depth. Each hermit crab and its respective shell were identified, weighted and measured. A total of 408 animals were captured, of families Paguridae and Diogenidae; the most abundant species were Dardanus insignis (de Saussure, 1858) and Loxopagurus loxochelis (Moreira, 1901). The animals occupied shells from 13 gastropod species, mainly of Buccinanops lamarckii (Kiener, 1834) and B. gradatum (Deshayes, 1844). Dardanus insignis utilized shells from 12 of the 13 mollusks species registered; L. loxochelis from nine ones. In a general way, the shell occupation patterns present a correlation between the hermit crab size and the shell size, in the case of the two most abundant species the strongest correlation was between their size/weight and shell aperture width, evidencing that shells occupation is given not only by their local availability, but also by the relationship between hermit crabs variables and gastropod shells.

It is registered for the first time in the Rio Grande do Sul coast, the crab Panopeus bermudensis Benedict & Rathbun, 1891, which previous southern limit of distribution was at Santa Catarina, and now it is extended to the Rio Grande do Sul state coast line. These crabs were colected at Cassino beach in Rio Grande city in midle of trash lycd with the high tide.

Is registered for the first time in the South Brazilian coast, the ermit crab Pagurus brevidactylus Stimpson, 1859, wich previous South limit of distribution was at São Paulo State and now it is extended to the Santa Catarina State coast line. Were collected 100 ermit crabs, being 50 males and 50 females, from wich 20 ovigerous were found. The organisms were collected by scuba diving in Ponta da Sepultura and Retiro dos Padres beach, on the rock and sand bottom, at Bombinhas city, in October and November 1995.