CONICET | Buscador de Institutos y Recursos Humanos

The phenotypic shell shape variation of Mactra isabelleana was tested using geometric morphometric method. Four localities were sampled along the Rio de la Plata estuary and the coast of Buenos Aires province. Principal component analysis (PCA) and Canonical variates analysis (CVA) of the first PCs were performed to reveal the shell variation and differences among localities, respectively. The specimens from different microhabitats were mostly overlap, although differences in shape were observed in the development of the umbo, the enlargement of the dorsoventral axes and the elongation of the posterior end. The ecological and physical parameters that could influence on shell shape variation are discussed.