SYDNEY (Reuters) - Australian scientists have discovered a new species of marsupial, about the size of a mouse, which conduct marathon mating sessions that often prove fatal for the male.

The Black-Tailed Antechinus has been found in the high-altitude, wet areas of far southeast Queensland and northeast New South Wales.

It is identifiable by a very shaggy coat and an orangey-brown coloured rump which ends with a black tail.

But it's their strenuous mating sessions, which can last for to 14 hours, with both the males and females romping from mate to mate, that is most striking about the animals.

"It's frenetic, there's no courtship, the males will just grab the females and both will mate promiscuously," Andrew Baker, head of the research team from the Queensland University of Technology who made the discovery, told Reuters.

The mating season lasts for several weeks and the males will typically die from their exertions.

Excessive stress hormones in the males that build up during the mating season degrade their body tissue, leading to death. Females have the ability to block the production of the hormone.

The species was found at the highest peak of the World-Heritage listed Gondwana Rainforests, in Springbrook National Park in Queensland, about 900 km (560 miles) north east of Sydney.

The findings about the new species have been published in the science journal Zootaxa.

(Reporting by Thuy Ong; Editing by Robert Birsel)