Macrofossils of Callicoma and Codia (Cunoniaceae) from Australian cainozoic sediments

Leaves, leaf fragments and two infructescences from five widespread Australian Cainozoic fossil localities, Little Rapid River, Lemonthyme Creek, Cethana (Early Oligocene), Berwick Quarry (Oligocene-Early Miocene) and Stuart Creek (Miocene-Pliocene) are assigned to, or validated as, the extant species Callicoma serratifolia Andrews. The extant species or, more likely, a very close relative, evolved prior to the Early Oligocene and has since remained relatively unchanged. It has become restricted to the forests of eastern mainland Australia, probably in response to climatic change during the Cainozoic. The first macrofossil of Codia, C. australiensis R.W.Barnes and R.S.Hill sp. nov., is described from West Dale (Middle Eocene-Oligocene), Western Australia, and has affinities with the juvenile foliage of at least one extant Codia species. Several structures of Callicoma and some Codia species (stomatal cutin frill/ledge and paired hair bases) may be synapomorphies for these genera. Callicoma serratifolia and Codia may share a unique common ancestor, or alternatively, C. serratifolia may represent a paedomorphic form of Codia.