The aim of the present work is to determine the paleobiological and paleoenvironmental significance of fossil concentrations of Heleobia Stimpson, 1865 (Gastropoda) deposited during the last transgressiveregressive cycle along the Atlantic coast. The work was divided into two stages : 1) the analysis of living populations of H. australis (d'Orbigny), I-1. conexa (Gaillard) and H. parchappii (d'Orbigny) in two estuarine environments from the southeastern coast of the Buenos Aires Province (Mar Chiquita coastal lagoon and Quequen Grande estuary) in order to know the range of variation of the main biological and ecological factors and 2) the paleoecological analysis of three holocene sequences from the same region (mouth of the Quequen Grande River, Mouth of... |