A New Early Pleistocene Species of Nothofagus and the Climatic Implications of Co-occurring Nothofagus Fossils

A new species of Nothofagus, N. pachyphylla, is proposed based on fossils from Early Pleistocene sediments at Regatta Point, western Tasmania. This extinct species occurred for some time with its sister species, N. cunninghamii, which is still extant in Tasmania. The fossil leaves of N. cunninghamii in the Regatta Point sediments are all very small and are only consistent with leaves from cold climate extant populations of this species. The fossil leaves of other taxa in these sediments are also mostly at the small (and cool climate) end of the range of the leaves of their extant relatives. These data provide corroborating evidence for floristically based inferences of colder than modern palaeoclimates for this fossil site. The co-occurrence of small- and large-leaved sister species is paralleled in a number of modern Tasmanian rainforest genera.