A team of Australian paleontologists has unearthed a trove of fossils on the island of Timor, including the bones of eight giant rat species.
The extant black-footed tree-rat (Mesembriomys gouldii), one of the largest murids found in Australia; by John Gould; from ‘Mammals of Australia,’ vol. III, plate 4, part of the 3 volumes.
The island of Timor, situated at the eastern end of the Indonesia archipelago, played host to an incredible diversity of giant rats spanning the late Quaternary, according to team leader Dr Julien Louys of the Australian National University.
At least eight species of giant rats, representing four genera, have been identified by Dr Louys and co-authors. Six of the species are entirely new to science.
“The biggest one was about 5 kg, about ten times the size of modern rats,” Dr Louys said.
Most of the rat remains were found in and immediately below archaeological deposits dated at 43,300 – 44,700 years.
Dr Louys holds the jaw bone of a giant rat species from East Timor and the same bone of a modern rat. Image credit: Stuart Hay / Australian National University.
“These are the largest known rats to have ever existed,” Dr Louys said.
“They are what you would call megafauna. Just to put that in perspective, a large modern rat would be 500 g,” he added.
The earliest records of humans on the island date to 46,000 years ago, and they lived with Timor’s giant rats for thousands of years.
“Evidence of butchery from the earliest archaeological deposits to the late Holocene indicates giant murids were regular prey items for humans for tens of thousands of years,” the scientists said.
Direct dating indicates that the rats probably became extinct about 1,000 years ago.
“Their persistence through the Last Glacial Maximum, moderate environmental disturbances, and disruption by introduced species echoes the ecological responses of smaller mammals found on continents and islands with long and complex histories,” Dr Louys and co-authors said.
The paleontologists reported their results October 16 at the 75th Annual Meeting of the Society of Vertebrate Paleontology in Dallas, Texas.
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Julien Louys et al. 2015. Holocene extinction of Timor’s endemic giant murid community, and implication for modern murid conservation on islands. 75th Meeting of the Society of Vertebrate Paleontology. Abstracts of papers, p. 167
