New species ofPhyllocladus(Podocarpaceae) macrofossils from southeastern Australia

Abstract

A study of the cuticular micromorphology of extant Phyllocladus species demonstrates that they can be separated into two distinct groups; P. aspleniifolius var. asplenifolius and var. alpinus, and P. glaucus, P. hypophyllus and P. trichmanoides. Phyllocladus macrofossils are common components of Tertiary and Quaternary deposits in Tasmania. The cuticular' micromorphology of the fossils determined from scanning electron micrographs, along with their gross morphology is described. Late Tertiary and Quaternary macrofossils are assigned to the extant Tasmanian P. aspleniifolius var. aspleniifolius. Early Tertiary macrofossils are assigned to three new species, P. aberensis which has close affinities with P. aspleniifolius var. aspleniifolius, and P. annulatus and P. lobatus, which are distinct from all extant species. P. morwellensis, the only macrofossil species previously known with organic preservation, is closest to the extant P. hypophyllus, which occurs from New Guinea to Borneo. P. lobatus is particularly distinct, and may represent a species with primitive photosynthetic organs in which webbing of the planated branch system is not complete, or it may be an advanced state, in which photosynthetic area has been reduced in response to the changing Tertiary climate.