Insights on the history of the scorched mussel Brachidontes rodriguezii (Bivalvia: Mytilidae) in the Southwest Atlantic: a geometric morphometrics perspective Berenice

MÁRQUEZ, FEDERICO; MARTÍNEZ SERGIO; TROVANT BERENICE; RUZZANTE DANIEL E.; DEL RÍO CLAUDIA; ORENSANZ JM

Historical Biology

Taylor & Francis

Año: 2017 vol. 30 p. 564 - 572

0891-2963

Some authors support the idea that an important part of the Miocene marine mollusc fauna is still represented in the Argentinean Province. The fossil mollusc Brachidontes lepida (Philippi) is considered a subspecies of the extant B. rodriguezii (dˈOrbigny), a taxon currently present in the ArgentineanBiogeographic Province. The aim of this study is to investigate the shell shape relationship between B.lepida and B. rodriguezii using geometric morphometrics. Samples of B. rodriguezii (n = 63) from four localities distributed in Uruguay and Argentina, of B. lepida from the Paraná Formation (n = 26) and of twoother extant Brachidontinae present in the region were included in this study. Canonical variate analyses showed that extant species differed in shell shape, with the discriminant function properly allocating 93% of the individuals to their respective species. Using the extant discriminant function, approximate 92% of B. lepida individuals were allocated to B. rodriguezii. This result suggests that B. lepida is more similar in shell shape to B. rodriguezii than to the other extant species present in the region. Considering the materialfrom the Pliocene of Cerro Laciar and from the Pleistocene deposits of Buenos Aires and Bustamante, the presence of B. rodriguezii from the Late Miocene in the warm temperate region is discussed.