Ciclo biológico de Simpulopsis ovata (Gastropoda, Bulimulidae) em São Francisco de Paula, Rio Grande do Sul, Brasil Biological cycle of Simpulopsis ovata (Gastropoda, Bulimulidae) in São Francisco de Paula, Rio Grande do Sul, Brazil

Abstract

The population growth of Simpulopsis ovata (Sowerby, 1822) from the Centro de Pesquisas e Conservação da Natureza - Pró-Mata, São Francisco de Paula, Rio Grande do Sul, Brazil, was studied along eleven months of 1996. Two discontinuous age classes were identified. The first one, with a monthly growth rate of 1.55 mm, was reproductively mature during April and May. The second one appeared after the previous group and had a monthly growth rate of 0.44 mm. The fact that no adults from the two age classes were found together is a characteristic of a semelparous species. New insights about its shell, pallial cavity and reproductive system are given. This is the first record of S. ovata for the State of Rio Grande do Sul.

Keywords

• Simpulopsis
• semelparity
• anatomy
• conquiliometry
• biological cycle