MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A geometric morphometric approach to the sexual dimorphism in Venericardia patagonica (Sowerby, 1846)
Autor/es:
DAMIÁN PÉREZ; CLAUDIA DEL RÍO; MAXIMILIANO ALVAREZ
Lugar:
Córdoba
Reunión:
Jornada; Reunión Anual de Comunicaciones de la Asociación Paleontológica Argentina; 2013
Institución organizadora:
Asociación Paleontológica Argentina
Resumen:
Venericardia patagonica (Sowerby) is one of the most common species of the Cenozoic of Patagonia. It is represented in the San Julian (Late Oligocene, Santa Cruz Province), Monte León (Early Miocene, Santa Cruz and Chubut Provinces), and Carmen Silva formations (early-late Miocene, Isla Grande de Tierra del Fuego Province). Two different morphotypes can be distinguished based on sculpture, outline and convexity. Sexual dimorphism is a rarity among bivalves, but carditids are one of the few cases with this dimorphism. Females breed the larvae into their umbonal cavity, and thus present a more convex and bulky shape. We developed a geometric morphometric analysis, using Elliptic Fourier Outlines. We used the anterior view of the valves, captured outlines of 95 specimens and performed a Principal Component Analysis with the Fourier coefficients. The results showed two well differentiated groups, based on development of the convexity, each of which would correspond to the mature male and female, as in other carditids. The females have more bulky shells, with maximum convexity at the centre of valves. The males have less bulky shells, with a sharp ventral edge. These two morphotypes correlate with sculpture (more pronounced in males) and outline differences (expanded ventral margin in females).