Presenter: Dr Dafne Koutamanis, Postdoctoral Research Fellow at Isotropics Geochemistry Lab, James Cook University

Abstract

Food webs play important roles in hypotheses on Pleistocene vertebrate evolution, such as megafauna evolution, insular dwarfism and gigantism, and Late Pleistocene extinctions. Yet, food webs reconstructions of Australasian Pleistocene fauna have been hindered by the lack of suitable trophic level proxies. In this seminar, I will talk about my PhD project, aimed at improving our understanding of food webs of Pleistocene Australian megafauna and island fauna from Flores (Indonesia) through novel tools in isotope geochemistry, namely calcium (Ca) and radiogenic strontium (Sr) isotopes.

Firstly, I will discuss a modern Tasmanian bare-nosed wombat dataset established as a reference for Ca and Sr isotopes. This dataset was compared with Pleistocene marsupial megaherbivores (i.e. Diproton, Procoptodon, Protemnodon) from Wellington Caves and Bingara, revealing insights into herbivorous diets and breastfeeding habits. These Ca and Sr isotopic compositions offer a baseline for Pleistocene predator food resources in Australia.

Secondly, I will present the preliminary food web reconstruction of Early- to Middle Pleistocene fauna from the So’a Basin, Flores, Indonesia. In addition to the ancestors of Homo floresiensis (nicknamed the hobbit), the So’a Basin was home to multiple reptile predators – Komodo dragons and crocodiles – and mammalian herbivores – pygmy elephants (Stegodon sondaari), a medium‑sized elephant (Stegodon florensis), and giant rats (Hooijeromys nusatenggara). Understanding the diets of these reptile carnivores and mammalian herbivores is a fundamental to for exploring the driving factors for insular evolution in Wallacea.

All are welcome to join in person: D003-003 (Nguma-bada - Cairns); 4-006 (Bebegu Yumba -Townsville)

Zoom link: https://jcu.zoom.us/j/86129107536?pwd=UEN0NGNULy9ZMHhDVG1wWVdUYXhJUT09&from=addon            Password: 174247