Interim report on the vertebrate deposits recovered from the Capricorn Caves, Rockhampton, Queensland

Abstract

Late Pleistocene to Holocene-aged microfaunal assemblages are rarely reported in Australia despite their critical importance for palaeoecological studies, as well as their bearing on the megafaunal extinction debate. Capricorn Caves, central-eastern Queensland, hosts three Late Pleistocene to Holocene deposits containing significant faunal records. Excavations were conducted on these deposits over several seasons, with analyses of recovered material ongoing. Here, we report interim results and explore their implications for our understanding of the microfaunal record of central eastern Queensland. Fern Chamber was previously dated using U-series to the Holocene (>7.6 ± 0.2 ka). Honeymoon Suite was dated to >6.4 ± 0.2 ka using U-series. However, new charcoal dates from the deposit span approximately 7.5–15.5 ka, although the association between charcoal and fauna is unresolved. The fauna is likely Holocene. Colosseum Chamber is the oldest of the deposits, and new single-grain luminescence ages and age-depth modelling suggest that the deposit likely spans MIS 1–4. We use abundant fragmentary rodent remains to examine palaeoenvironmental change over this period. Carbon and oxygen isotope analyses of rodent incisor fragments reveal broad diets within the rodent community, and significant differences in precipitation between glacial and interglacial conditions. Rodent long bone histological analyses indicate significant differences in bone metabolism at the family level between the MIS 3 and 2 samples, but not MIS 1. We suggest that these data support evidence for a mid-Holocene arid anomaly in the region, and increased aridity through the Holocene relative to the terminal Pleistocene. The sites contain at least 10 small mammal species either globally extinct or locally extirpated, including the Capricorn rabbit-rat (Conilurus capricornensis), the white-footed rabbit-rat (Conilurus albipes), the plains mouse (Pseudomys australis), Gould’s mouse (Pseudomys gouldii), Forrest’s mouse (Leggadina forresti), the long-tailed hopping mouse (Notomys longicaudatus), swamp rat (Rattus lutreolus), the white-tailed rat (Uromys caudimaculatus), the narrow-nosed planigale (Planigale tenuirostris), the Liverpool Plains striped bandicoot (Perameles fasciata), the Cape York brown bandicoot (Isoodon peninsulae), and the southern brown bandicoot (Isoodon obesulus). We also record significant range contractions for frogs (Philoria sp., Neobatrachus sp.) and earless dragons (Tympanocryptis sp.). This study demonstrates that significant changes in the microfaunal community of tropical Queensland occurred between the Late Pleistocene and the late Holocene. It also reinforces how poorly recorded native faunas are from the late Holocene through the historical period, to today. Such records underpin and are thus vital for modern biodiversity conservation efforts.

Julien Louys [[email protected]], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Australia; Jonathan Cramb [[email protected]], Queensland Museum, Brisbane, Australia; Kyle Ferguson [[email protected]], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia; Justine Kemp [[email protected]], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Australia; Rachel Wood [[email protected]], School of Archaeology and Anthropology, Australian National University, Canberra, Australia and Oxford Radiocarbon Accelerator Unit (ORAU), University of Oxford, Oxford, UK; Justyna J. Miszkiewicz [[email protected]], School of Social Science, University of Queensland, Brisbane, Australia and Naturalis Biodiversity Center, Leiden, the Netherlands; Nathalia R. Dias Guimarães [[email protected]], School of Archaeology and Anthropology, Australian National University, Canberra, Australia; Penny Higgins [[email protected]], EPOCH Isotopes, 6606 E Townline Road, Williamson, NY 14589, USA; Kenny J. Travouillon [[email protected]], Western Australian Museum, Perth, Australia; Scott A. Hocknull [[email protected]], Geosciences, Queensland Museum, Brisbane, Australia; Gregory E. Webb [[email protected]], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia; Gilbert J. Price [[email protected]], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia.

Keywords:

• extinction
• climate change
• carbon and oxygen isotopes
• bone histology
• microfauna
• rodents
• late Quaternary

Acknowledgements

We acknowledge the Darumbal People on whose land the Capricorn Caves are situated, and we pay respects to their Elders, past, present and future. We thank the late Ann Augustyn and her family for their unfailing support of the research undertaken at Capricorn Caves. She and the staff from the Capricorn Caves generously provided assistance whenever requested, and kindly facilitated access to the caves and accommodation. Kristen Spring facilitated access to the Colosseum Chamber fossil collection in the Queensland Museum. Trevor Worthy aided in the identification of the birds. We thank many supporters and volunteers who have worked with us on the fossil deposits of the Capricorn Caves, especially Noel Sands and family, Rochelle Lawrence, Nicholas Wiggins, and the volunteers of the UQ Palaeontology Lab. We thank the ANU School of Archaeology and Anthropology for facilitating access to their Histology Lab. We thank three anonymous reviewers whose comments helped improve this manuscript.

Additional information

Funding

This research was funded by a University of Queensland Postdoctoral Fellowship (to JL), an Ian Potter Foundation grant (to JL, SAH, GJP), an Australian Research Council (ARC) Discovery Grant [DP120101752], ARC Linkage Grants [LP0453664 and LP0989969], ARC Discovery Early Career Researcher Award [DE120101533], an Australian Institute of Nuclear Science and Engineering grant [AINGRA09002].