The discovery of a new animal species is an exciting event in the scientific community, although it does not often catch the public’s attention like the three marsupial species recently found in Queensland, Australia. These species have gained this attention, not because they are more significant than other species, but because they have unusual sexual practices that result in mass deaths of adult males at the end of the mating season.
These three species are marsupials of the genus Antechinus. Marsupials are popularly characterized as pouched mammals. Marsupial babies are practically still embryos when they are born. Virtually helpless, they crawl to their mother’s pouch, where they stay until they are more developed. Members of the Antechinus genus of marsupial are carnivorous and look similar to mice.
So far, only one of the new Antechinus species, the black-tailed antechinus (Antechinus arktos) has been announced, and it has been described in the biology journal Zootaxa. Because of its similarity to the dusky antechinus (Antechinus swainsonii mimetes), the black-tailed antechinus has not, until now, been recognized as its own species.
Doctor Andrew Baker and his team at the Queensland University of Technology discovered the new species. He told the Guardian, “It’s a very exciting time to be a mammalogist. Typically, there’s only a couple of new species of mammals found worldwide each year. So to find three new species of this marsupial, all in South-East Queensland, is really exciting.”
The black-tailed antechinus lives at the highest peak of the Gondwana rainforests in Springbrook National Park, where it is secluded from others of its genus. It has a distinctive dark tail and a hairy coat suited to the cold, wet environment. Genetic characteristics, found through mitochondrial DNA sequencing, confirmed that this animal is indeed its own species. Baker believes that it is very likely that the black-tailed antechinus partakes in the same unique breeding behavior as others of its genus.
Antechinus species became renowned in 2013 when it was discovered that they exhibit semelparity, a reproductive strategy in which individuals take part in a single mating season before dying. Antechinus males are sexually mature at 11 months old, at which age they commence their breeding frenzy. They mate for weeks on end, in sessions of up to 14 hours. By the end of the breeding season, the males are “physically disintegrating,” as described by Diana Fisher of the University of Queensland. The same hormones that send the males into this frenzy may also degenerate their muscles and compromise their immune systems. They ultimately die from stress, infection, or internal bleeding.
Semelparity is common in salmon and some insects, but occurs among mammals only in the genus Antechinus. This breeding behavior is a strange but fruitful evolutionary strategy. The more a male copulates, the more offspring he will produce, thus ensuring that his genes are passed on.
The black-tailed antechinus is thought to be a rare species. Because of global climate change, it is further threatened by the loss of its mountainous rainforest habitat. Baker and his team have applied to put the black-tailed antechinus on the endangered species list.
