Giant Burrowing Bat Fossils Found

The fossilized remains of a giant burrowing bat that lived in New Zealand millions of years ago have been found by a University of New South Wales  (UNSW) Sydney-led international team of scientists.

Teeth and bones of the extinct bat – which was about three times the size of an average bat today – were recovered from 19 to 16-million-year-old sediments near the town of St Bathans in Central Otago on the South Island.

The study, by researchers from Australia, New Zealand, the UK and USA, is published in the journal Scientific Reports.

Burrowing bats are only found now in New Zealand, but they once also lived in Australia. Burrowing bats are peculiar because they not only fly; they also scurry about on all fours, over the forest floor, under leaf litter and along tree branches, while foraging for both animal and plant food.

An artist’s impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. The new fossil find, Vulcanops jennyworthyae, that lived millions of years ago in New Zealand, is an ancient relative of burrowing or short-tailed bats.

Credit:  Illustration by Gavin Mouldey.

With an estimated weight of about 40 grams, the newly found fossil bat was the biggest burrowing bat yet known. It also represents the first new bat genus to be added to New Zealand’s fauna in more than 150 years

It has been named Vulcanops jennyworthyae, after team member Jenny Worthy who found the bat fossils, and after Vulcan, the mythological Roman god of fire and volcanoes, in reference to New Zealand’s tectonic nature, but also to the historic Vulcan Hotel in the mining town St Bathans.

Other research team members include scientists from UNSW Sydney, University of Salford, Flinders University, Queensland University, Canterbury Museum, Museum of New Zealand Te Papa Tongarewa, the American Museum of Natural History, and Duke University.

“Burrowing bats are more closely related to bats living in South America than to others in the southwest Pacific,” says study first author and UNSW Professor Sue Hand.

The fossil dig site at St Bathans in New Zealand where the fossilised remains of an extinct giant burrowing bat, Vulcanops jennyworthyae, were found.

Credit: Trevor Worthy.

“They are related to vampire bats, ghost-faced bats, fishing and frog-eating bats, and nectar-feeding bats, and belong to a bat superfamily that once spanned the southern landmasses of Australia, New Zealand, South America and possibly Antarctica.”

Around 50 million years ago, these landmasses were connected as the last vestiges of the southern supercontinent Gondwana. Global temperatures were up to 12 degrees Celsius higher than today and Antarctica was forested and frost-free. With subsequent fragmentation of Gondwana, cooling climates and the growth of ice-sheets in Antarctica, Australasia’s burrowing bats became isolated from their South American relatives.

“New Zealand’s burrowing bats are also renowned for their extremely broad diet. They eat insects and other invertebrates such as weta and spiders, which they catch on the wing or chase by foot. And they also regularly consume fruit, flowers and nectar,” says Professor Hand, who is Director of the PANGEA Research Centre at UNSW.

“However, Vulcanops’s specialized teeth and large size suggest it had a different diet, capable of eating even more plant food as well as small vertebrates – a diet more like some of its South American cousins. We don’t see this in Australasian bats today,” she says.

Study co-author, Associate Professor Trevor Worthy of Flinders University says: “The fossils of this spectacular bat and several others in the St Bathans Fauna show that the prehistoric aviary that was New Zealand also included a surprising diversity of furry critters alongside the birds.”