The reproductive cycle and development of Crepipatella fecunda (Gastropoda: Calyptraeidae) from southern Chile

Abstract

Crepipatella fecunda is a benthic, primarily suspension-feeding gastropod that occurs in great abundance along the Chilean coast. It is a protandrous species whose reproduction involves brooding of an encapsulated embryonic stage followed by the release of free-living planktotrophic larvae. Because its close sister species, C. dilatata, co-occurs with C. fecunda, understanding the details of reproduction in this species might shed light on differences in reproductive features that correlate with divergences in mode of development. In southern Chile, brooding occurs throughout the year except for May and June, and each female produces 3–7 broods. The smallest brooding female was 28·2 mm in shell length and the largest was 56·3 mm. All full-grown eggs from the ovary are deposited at one time in a single brood, and only smaller oocytes remain in the gonad after the female finishes ovopositing. Those females that host pinnotherid crabs do not deposit eggs. All the eggs develop into embryos whose intracapsular development is similar to Crepidula fornicata and Crepipatella lingulata. Planktotrophic larvae hatch at a mean shell length of 329·5 μm (SD=27·09) after 4–5 weeks. During the pelagic stage the shell and velum of the larvae grow, but little other morphological development is visible externally. The pelagic stage lasts for 15–16 days at 17°C, during which the larvae grow ∼20·7 μm d⁻¹. Observations of cultured larvae and protoconchs of field-collected juveniles show that settlement occurs when the larvae reach a shell-length of 650 μm (SD=28·3 μm).