Melbourne, June 18 (IANS): Researchers have discovered fossilised remains of a bat species in New Zealand, which lived 16 million years ago, walked on four limbs and was three times larger than today's average bat.

The new species, Mystacina miocenalis, was described in the journal PLOS ONE, and is related to another bat, Mystacina tuberculata, which still lives in New Zealand's forests.

"Our discovery shows for the first time that Mystacina bats have been present in New Zealand for upwards of 16 million years, residing in habitats with very similar plant life and food sources," said lead author Suzanne Hand, associate professor at the University of New South Wales (UNSW) in Australia.

The new species has similar teeth to its contemporary relative, suggesting a broad diet that included nectar, pollen and fruit, as well as insects and spiders. Limb bones found in the deposit also showed similar structures specialised for walking.

Where they differ is body size: at an estimated 40 gm, the fossil bat is roughly three times heavier than its living cousin and the average weight of more than 900 living bat species.

"The size of bats is physically constrained by the demands of flight and echolocation, as you need to be small, quick and accurate to chase insects in the dark."

"The unusually large size of this bat suggests it was doing less in-flight hunting and was taking heavier prey from the ground, and larger fruit than even its living cousin," Hand said.