Plant-macrofossil assemblages during Pliocene uplift, South Island, New Zealand

Abstract

Organically preserved plant macrofossils, which accumulated during the period of late Neogene tectonic uplift, were documented from four localities in the South Island. These include Arapito Road (near Karamea), Waitahu River (near Reefton), Tadmor (south of Nelson) and Grey River (north of Christchurch). The assemblages from these localities were species-poor compared with older Cenozoic assemblages, but included a range of conifers and angiosperms. Of note was the presence of Acmopyle (currently extinct in New Zealand) and Cupressaceae in all four localities. At least two new species of Acmopyle were present, with leaf shapes distinctly different from any currently known. One of them (A. kirrileeae sp. nov.) had unflattened, awl-like foliage, whereas the other (A. biformis sp. nov.) had dimorphic foliage, including very distinct bilaterally flattened leaves with a mucronate apex. Both of these were distinct from the flattened foliage, which predominates on extant Acmopyle. Other conifers included Araucaria, Dacrycarpus, Dacrydium, Phyllocladus and Libocedrus. Angiosperms included Beauprea (now extinct in New Zealand) Beilschmiedia, Knightia sp., Metrosideros, Nothofagus and probably Pseudowintera, Pseudopanax and Cunoniaceae. The assemblages suggest temperate conditions.