Search

Your search keyword '"Farinati, Ester"' showing total 3 results
Start Over Author "Farinati, Ester" Topic holocene Language english
3 results on '"Farinati, Ester"'

2. Bioerosion structures in Crepidula (Mollusca, Gastropoda) as indicators of latitudinal palaeoenvironmental changes: Example from the marine Quaternary of Argentina

Author

Davies Karen, Aguirre Marina, Farinati Ester, Castellanos Ignacio, and Richiano Sebastián

Subjects
PLEISTOCENE, Oceanography, SOUTHWESTERN ATLANTIC, Ciencias de la Tierra y relacionadas con el Medio Ambiente, Gastropoda, HOLOCENE, Crepidula, Mollusca, Ecology, Evolution, Behavior and Systematics, Holocene, Earth-Surface Processes, GEOGRAPHICAL VARIATIONS, biology, Ecology, Bioerosion, Entobia, Paleontology, biology.organism_classification, PALAEOCEANOGRAPHICAL CHANGES, Interglacial, Quaternary, Meteorología y Ciencias Atmosféricas, ICHNODIVERSITY, Geology, CIENCIAS NATURALES Y EXACTAS
Abstract

Late Quaternary marine skeletal concentrations from Argentina are rich in molluscs exhibiting a great variety of bioerosion structures. The shells of Crepidula, a characteristic gastropod occurring along more than 2000. km of coastline between the Río de La Plata margin and southern Patagonia, show traces of dwelling, predation and anchoring activities made by porifers, bryozoans, annelids, other gastropods and brachiopods. Caulostrepsis, Entobia, Maeandropolydora, Iramena, Oichnus, Finichnus, Pennatichnus, Pinaceocladichnus, Podichnus and Renichnus occur on the outer shell surface. Finichnus and Oichnus are the only traces present along the entire area and the full time span considered. The most characteristic structures are produced by bryozoans, polychaetes and predatory gastropods. Traces produced by annelids and predatory gastropods occur preferentially in the central shell sector, where predators gained access to the soft parts of the prey. By contrast, encrusting or branching bryozoan colonies are widely distributed as they can attach to any sector regardless of shell features available. No strict correlation is evident between ichnodiversity and either time or latitude, but ichnodiversity is linked to local oceanographical/biotic controls. For Patagonia, with a great majority of ichnotaxa made by bryozoans, the general trend of higher bioerosion degree and ichnodiversity at higher latitudes is controlled by sea surface temperature/productivity: for the modern and the Holocene, several ichnodiversity peaks match with well-constrained conditions (substrate, salinity, thermal fronts). By contrast, this does not hold for the Pleistocene: dissimilar conditions probably prevailed, especially during the Last Interglacial (colder waters richer in nutrients). Fil: Richiano, Sebastián Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Aguirre, Marina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Farinati, Ester Amanda. Universidad Nacional del Sur; Argentina Fil: Davies, Karen. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Castellanos, Ignacio. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

Published
2015

3. Reading shell shape: implications for palaeoenvironmental reconstructions. A case study for bivalves from the marine Quaternary of Argentina (south-western Atlantic).

Author

Aguirre, Marina L., Richiano, Sebastián, Álvarez, Alicia, and Farinati, Ester A.

Subjects
BIVALVES, HOLOCENE Epoch, VENEROIDA, MORPHOMETRICS, SHELL deposits
Abstract

Most research on bivalves from the south-western Atlantic used morphological (shell) characters for taxonomic discriminations. Dominant Veneroids from Argentinian Quaternary coastal deposits exhibit wide morphological variation – often making objective discriminations difficult/impossible, which could be objectively described and compared through geometric morphometrics techniques. This work focuses on comparison of geometric morphometrics methods applied to fossil and modern shells, to assess inter- and intra-generic variations. Three approaches were considered: landmarks (L), semi-landmarks (SL) and outlines. Shell shape analyses for different time spans (Pleistocene, fossil Holocene and modern) and areas (Patagonia and Bonaerensian) showed that Elliptic Fourier analysis (EFA), Landmarks and Landmarks plus Semilandmarks (L+SL) can discriminate at generic levels:Mactra, Mulinia(Mactridae) vs.Pitar, Protothaca, Eurhomalea, Clausinella(Veneridae). L and L+SL are powerful for inter/intraspecific distinctions ofMactra. Variability ofMactra isabelleanaincludes the remaining nominal ‘species’ (transitional morphs). Causal environmental factors of (phenotype) variation could be addressed for modern environments (substrate, salinity and energy). Subtrigonal-inflated shells predominate in muddy, quieter, shallow mixo-polyhaline waters; ovate-elongate-compressed in sandy, poly-euhaline, deeper habitats. Differential spatial distribution (and abundance) across time responds to Late Quaternary high sea-level stands: transgressive maxima allowed higher salinity in marginal-marine areas and optimal conditions forMactra isabelleanacontrasting with scarcer records in the Mar Argentino today. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results