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

Abstract

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 StuartCreek (Miocene–Pliocene) are assigned to, or validated as, the extantspecies Callicoma serratifolia Andrews. The extantspecies or, more likely, a very close relative, evolved prior to the EarlyOligocene and has since remained relatively unchanged. It has becomerestricted to the forests of eastern mainland Australia, probably in responseto climatic change during the Cainozoic. The first macrofossil ofCodia, C. australiensis R.W.Barnes & R.S.Hill sp. nov., is described from West Dale (MiddleEocene–Oligocene), Western Australia, and has affinities with thejuvenile foliage of at least one extant Codia species.Several structures of Callicoma and someCodia species (stomatal cutin frill/ledge and pairedhair bases) may be synapomorphies for these genera.Callicoma serratifolia and Codiamay share a unique common ancestor, or alternatively,C. serratifolia may represent a paedomorphic form ofCodia.