I’m part of a research project studying the effects of environmental change on the animals of tropical Queensland over the last half-million years. This is a pretty long stretch of time (by human standards, anyway), and it includes some major changes in Queensland’s environment. One of the big shifts that we’ve identified is the widespread extinction of rainforest habitats in eastern Queensland. We find the best fossils of this extinct rainforest in the limestone caves north of Rockhampton (including Capricorn Caves). Part of this project involves the naming of new species of extinct animals. Almost the entire assemblage of rainforest species is extinct, so we’ve got plenty of new species to name.
Researchers excavating a dig pit in Colosseum Chamber at Capricorn Caves – Rochelle Lawrence.
One of these has just been named Leggadina webbi, commonly called Webb’s Short-tailed Mouse. This is a tiny native mouse that inhabited the ancient rainforest. This discovery is pretty unexpected, as the two, living species of short-tailed mice live in dry and arid habitats. So far, L. webbi is the only species of short-tailed mouse that we know inhabited rainforests. After L. webbi became extinct (along with its rainforest habitat), another short-tailed mouse took its place. Leggadina forresti, Forrest’s Short-tailed Mouse, lives in the central deserts of Australia today, but we also find its fossil remains at Capricorn Caves. This is one of several fossil species that indicate very dry local conditions in the past.
Left, fossil jaw of a Leggadina forresti, Forrest’s Short-tailed Mouse – Jonathan Cramb. Right, Jonathan searching for fossils in the limestone cave chambers at Capricorn Caves – Rochelle Lawrence.
My colleagues and I also named another new species of short-tailed mouse, Leggadina irvini, that I found in a cave much further north, near Chillagoe. This species was also unusual in comparison to living species, because it was much larger than the other known species of Leggadina. These two new species are small pieces of the puzzle that we’re slowly reassembling. As we work, we’re getting glimpses of the larger image: the changes in the environment that have shaped tropical Queensland as it is today.
This project is a collaboration between researchers at the University of Queensland and the Queensland Museum, and is made possible by the assistance of Capricorn Caves, Central Queensland Speleological Society, Chillagoe Caving Club, Queensland National Parks and Wildlife Service and the support of researchers, staff and volunteers.
You can access this publication from here: https://peerj.com/articles/5639/
Discover Queensland’s ancient rainforests and unique creatures on a fossil experience at Capricorn Caves: http://capricorncaves.com.au/tours/
By Jonathan Cramb, Palaeontologist at Queensland Museum and the University of Queensland