MACNBR   00242
MUSEO ARGENTINO DE CIENCIAS NATURALES "BERNARDINO RIVADAVIA"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Origin and dispersion of the Cenozoic genera Amiantis Carpenter, 1864 and Eucallista Dall, 1902 (Veneridae, Pitarinae)
Autor/es:
ALVAREZ, MAXIMILIANO; DEL RIO, CLAUDIA JULIA
Lugar:
Burgos
Reunión:
Congreso; XXI Reunión Bienal de la Real Sociedad Española de Historia Natural; 2015
Institución organizadora:
Real Sociedad Española de Historia Natural
Resumen:
The confuse and difuse systematic information prevailing during almostthe last 100 years, has linked the history of the pitarinae genera Amiantis tothat of Eucallista, leading to misinterpretations about their origin, dispersionand phylogenetic relationships. A careful survey of the more than a dozennominal species longely assigned to Aminatis, has allowed to provide accuratediagnostic characters that differentiate this genus from Eucallista. Moreover it has been possible to restrict the presence of Amiantis to the tropical región of Western North America, and that of Eucallista to the Argentinean and Brasilean Bioprovinces of the Southwestern Atlantic Ocean. While the Neogenerecord indicates that Amiantis would have originated in the California regiónduring the Oligocene, where remained confined until nowadays, the oldestknown record of Eucallista occurred in the Early Miocene of the middle latitudes of Chile. This taxon inhabited the Chilean and Peruvian coasts until Pliocene, but dispersed into Patagonia in Late Miocene times, where it remaineduntil Recent times, migrating northwards to northern Brazil anytime duringQuaternary. These findings prove that both genera are not related as previouslystated, and that a probable source of confusion could have been thepresence of convergent characters such as the development of rugose nimphsin both taxa. According to the present research, Eucallista purpuratus Lamarck,1818, the type species, would have originated during Pleistocene time in theSouthwestern Atlantic Ocean contrary to that supposed by previous authorswho considered this species as a Miocene relict taxon. E. purpuratus has notbeen recorded in the area earlier than the Pleistocene and has been usuallymixed up with E. laziarina (Ihering, 1907), the only Miocene species of thegenus that has been recorded in Chile (Navidad Formation, Early Miocene)and Argentina (Puerto Madryn Formation, Late Miocene; ?Araucaense beds?,Early Pliocene). Systematic and phylogenetic analyses presently carriedout indicate that E. purpuratus could have evolved from E. laziarina duringPleistocene.This is a contribution supported by the Research Projects ANCyP PICT57 and CONICET PIP 320.