Quaternary molluscan faunas from the island of Tierra del Fuego after the Last Glacial Maximum

Abstract

Palaeontological studies on postglacial molluscan faunas from marine deposits located along the northern coast of the Beagle Channel (lat. 54°55'S, long. 68°34'-67°11'W) showed differences of various molluscan assemblages during a period of climatic stability after deglaciation. Oceanographic changes, different local environmental conditions and/or episodes of minor climatic fluctuations are pointed out as causes for the variations in faunal composition. Comparison with Quaternary molluscs from Antarctica showed that these palaeofaunas overlap slightly at the species level, but have a considerable number of genera (23%) and families (50%) in common. These affinities and relationships are better explained on the basis of more recent migrating taxa than by ancient connections when the two regions formed part of the Weddellian Province.