In a study led by the Australian National University (ANU) and published in the Molecular Ecology journal, two new species of mice were identified in different regions of Australia.
Not your average house mouse
According to the study, native rodents have existed in Australia for around five million years. In fact, there are more than 150 rodent species in Australia and New Guinea that can be found nowhere else in the world.
The two recently discovered species belong to a group of rodents known as delicate mice. These tiny creatures weigh up to six grams, though most are even smaller. The Atlas of Living Australia reveals that the delicate mouse is mostly found in sandy savanna climates, making nesting chambers in hollow logs, burrows, or under large pieces of bark. The delicate mouse diet consists of grass seeds, plant matter and some invertebrates, foraged at night.
Also known as Molinipi (Pseudomys delicatulus), the delicate mouse was previously thought to be a single species located in Western Australia, the Northern Territory, Queensland and New South Wales.
However, experts have now realised that the delicate mouse is in fact three species inhabiting different locations. Each of these species are genetically distinct, and their non-compatible sperm and chromosomes make it unlikely for interbreeding to occur
The mice have been given new names in order to account for their differences. The “northern delicate mouse” will keep the original scientific name of Pseudomys delicatulus. The “western delicate mouse,” found mostly in Western Australia, is now known as Pseudomys pilbarensis or Kalunyja in the Kariyarra language. Similarly, the “eastern delicate mouse,” located in Queensland and New South Wales, is known as Pseudomys mimulus or Kalla in the Wik-Mungkan language.
The discovery of multiple delicate mice species was made using genomic sequencing, as well as data on reproductive traits and high-resolution CT scans.
Western delicate mouse © Ian Bool
Changing the story
According to a study in the Proceedings of the National Academy of Sciences (PNAS), Australia has some of the most unique mammal species in the world, with 87 percent of the 316 terrestrial species endemic to the continent. This means that protecting native animals is vital to the maintenance of this distinct and beautiful ecosystem. Sadly, native rodents are one of Australia’s most threatened land mammal groups due to the introduction of invasive species such as feral cats and red foxes.
While the delicate mouse has not been the focus of conservation efforts in the past, research models developed by ANU reveal that 95 per cent of current delicate mouse habitats may become uninhabitable by 2100 given current global warming rates.
Equally, while experts previously believed that one species of delicate mouse was spread across a large proportion of Australia, the distinction of three unique species has now lowered estimated population levels, suggesting that delicate mice may be more at risk than expected.
This has encouraged recognition of the immediate threats to delicate mice, and a plan to reassess the conservation status of all three species in order to protect them for the future.
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Featured image: Eastern delicate mouse © Justin Wright