The fossil record of Icacinaceae in Australia supports long-standing Palaeo-Antarctic rainforest connections in southern high latitudes

Abstract

ABSTRACT Fossil fruits of Icacinaceae are recorded from two Cenozoic sites in Australia, at Launceston in northern Tasmania and the Poole Creek palaeochannel in northern South Australia, representing the first report of fossil Icacinaceae from Australia. The Launceston material includes two endocarps with broad surface pits/tubercles and is referred to Palaeophytocrene. It is interpreted to have a minimum middle to late Eocene age. Two specimens are recorded from the Poole Creek palaeochannel; a mid-Miocene or middle Eocene age is possible for this site, but the older age (middle Eocene) is considered more likely. These specimens represent partial endocarps, one documenting the wall thickness and internal structures of the endocarp, and the other documenting the morphology and dimensions of the endocarp surface pits. The combination of characters shown by these fossils is unique among extant and fossil Icacinaceae genera, warranting the recognition of a new genus, Manchesteria gen. nov. These fossils document an early Cenozoic history for the Phytocreneae (Icacinaceae) in Australia and provide additional evidence that the family was broadly distributed during the globally warm Eocene. Along with recently documented African and South American fossil records, these fossils indicate a significant but little understood Gondwanic history for the family.