Quaternary fossil faunas from caves in the Punakaiki area, West Coast, South Island, New Zealand

Abstract

The late Quaternary fossil vertebrate faunas from 42 caves in Oligocene limestones of the Barrytown Syncline, Westland, New Zealand, are described and discussed. The depositional environments in cave sites in the area are described and interpreted. Several major sites, including Metro Cave, Madonna Cave, and Te Ana Titi, are described in detail. The Hermit's Cave deposit is probably derived from pellets ejected by laughing owls (Sceloglaux albifacies) at one of their roost sites. Radiocarbon dating shows that the faunas were laid down at various times during the past 25,000 years. A date of 25,070 years is the oldest so far obtained from any cave fossil in New Zealand. The fossil fauna consisted of 50 species of bird, three frogs, one skink, one gecko, one tuatara, and two or possibly three bats. They comprised two distinct faunal assemblages. A glacial fauna, dating from the last (Otira) Glaciation and Late Glacial periods, between 10,000 and 25,000 radiocarbon years ago, contained taxa typical of Holocene deposits in the east and south of the South Island. A Holocene fauna, deposited during the past 10,000 years, contained taxa typical of the West Coast forests at the time of European contact, plus extinct taxa. The Otiran fauna was characterised by the moas Pachyornis elephantopus, Euryapteryx geranoides, and Megalapteryx didinus (only large morphs), the goose Cnemiomis calcitrans, and Finsch's duck Euryanas finschi. These were absent from the Holocene fauna, which included the moas Anomalopteiyx didiformis. Dinornis struthoides, Dinornis novaezealandiae, and only small morphs of Megalapteryx didinus. Kakapo (Strigops habroptilus) were common during the Holocene. Kiwi (Apteryx spp.), weka (Gallirallus australis), snipe (Coenocorypha cf. aucklandica), New Zealand pigeon (Hemiphaga novaeseelandiae), parakeets Cyanoramphus spp., tui (Prosthemadera novaeseelandiae), robin Petroica australis, tomtit P. macrocephala, yellowhead Mohoua ochrocephala, rifleman Acanthisitta chloris, bush or rock wrens Xenicus spp., stout-legged wren Pachyplichas yaldwyni, piopio Turnagra capensis, kokako (Callaeas cinerea), and saddleback (Philesturnus carunculatus) were present in both periods. The presence of this diverse small bird fauna in deposits of Otiran glacial age shows that some tall shrubland or forest vegetation survived in the sheltered valleys of the Punakaiki area even during the coldest period about 18,000 radiocarbon years before present (yrs BP). The Holocene fauna is assumed to have lived in vegetation similar to that found by the first Europeans, i.e. wet, dense, podocarp-hardwood forest, with swamp vegetation on riverbed flats. An undescribed species of Puffinus shearwater similar to the extant Puffinus gavia was abundant in deposits throughout the study area, with dates ranging from at least 18,000 yrs BP to < 600 yrs BP; it is also known from the northwest South Island. Fossils of the Westland petrel (Procellaria westlandica) are recorded for the first time, and the fossil range of the black petrel (Procellaria parkinsoni) includes the Barrytown Syncline. The two species were, therefore, sympatric in the Holocene. The black-bellied storm petrel Fregetta tropica is recorded as a fossil from the mainland South Island for the first time, probably as a population morphologically distinct from those presently breeding on subantarctic islands south of New Zealand.