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| Title: | Significado paleobiológico y paleoambiental de las concentraciones holocenas de Heleobia (Gastropoda) presentes en el sudeste de la provincia de Buenos Aires. |
| Authors: | De Francesco, C.G. |
| Theses advisor: | Isla, F.I.
Farinati, E.A. |
| ASFA Terms: | Palaeoenvironments
Palaeoecology
Spatial variations
Comparative studies
Taxonomy
Morphometry
Abundance |
| Issue Date: | 2002 |
| Abstract: | 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 La Ballenera Creek and Punta Hermengo) to contrast the
results obtained in modern environments . The comparisson of both methods allowed the recognition of
spatial and temporal patterns of variation in the distributional ecology and morphology of species . All
Heleobia species showed a high degree of ecological and phenotypic plasticity, allowing the recognition of
distinct environmental conditions during the Holocene. H. australis has not significantly changed its
ecological requirements during the Holocene, resulting a good bioindicator of environments close to the
coast where exist a marked tidal influence . On the other hand, the distribution ofK parchappii has varied
along the Holocene, being actually represented only in environments far away from the marine influence,
whereas it was present in both coastal and freshwater environments during the maximum transgressive . H.
conexa is not recorded in the southeastern Buenos Aires prior to 2,500 years BP. |
| URI: | http://hdl.handle.net/1834/2971 |
| Appears in Collections: | Tesis En Ciencias Marinas
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