Revealed: The giant bat that roamed NZ
New Zealand was once home to a burrowing bat that was three times the size of the average bat today.
The extinct creature, which weighed about 40g, represents the largest burrowing bat known to science, and New Zealand’s first new bat genus for more than 150 years.
Fossil teeth and bones of the bat were recovered from sediments dated between 16 and 19 million years old, found near the old Central Otago gold and coal mining town of St Bathans.
Burrowing bats, now found only in New Zealand, are peculiar because they not only fly but also scurry about on all fours over the forest floor, under leaf litter and along branches.
It has been named Vulcanops jennyworthyae, after Jenny Worthy, who was part of the team which found the fossils, and after Vulcan, the mythological Roman god of fire and volcanoes, in reference to New Zealand’s tectonic nature, and a nod to St Bathans’ historic Vulcan Hotel.
Its discovery has been revealed in a study just published in the international journal Scientific Reports.
“Burrowing bats are more closely related to bats living in South America than to others in the southwest Pacific,” said Professor Sue Hand of the University of New South Wales.
“They are related to vampire bats, ghost-faced bats, fishing and frogeating bats, and nectar-feeding bats, and belong to a bat superfamily that once spanned the southern landmasses of Australia, NZ, South America and possibly Antarctica.”
About 50 million years ago, these land masses were connected as the last vestiges of the southern supercontinent Gondwana. At that point, global temperatures were up to 12C higher than today and Antarctica was forested and frost-free.
With the break-up 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,” said Hand.
They eat insects, weta and spiders, and like fruit, flowers and nectar.
“However, Vulcanops’ specialised teeth and large size suggest it had a different diet, capable of eating even more plant food as well as small vertebrates . . . more like some of its South American cousins. We don’t see this in Australasian bats today.”
The species is the latest addition to what scientists call the St Bathans Fauna. They lived in or around a 5600sq km prehistoric lake, Lake Manuherikia, that once covered much of the Maniototo region.
When they lived, in the early Miocene, NZ temperatures were warmer than today and semitropical to warm temperate forests and ferns edged the vast palaeo-lake.
Vulcanops’ lineage became extinct some time after the early Miocene epoch.
Auckland Council senior biodiversity adviser Ben Paris, better known as NZ Batman, said the discovery was “extremely exhilarating news” for the bat world in NZ.