‘Delicate’ rodent species went undetected in Australia for millions of years — until now

Two species of tiny rodents have lived undetected in Australia for millions of years — until now.

The species were discovered when researchers took a closer look at delicate mice, the continent’s smallest rodents, which were thought to comprise just a single species.

Upon analyzing the creatures’ genes, researchers revealed that delicate mice, in fact, are three separate species, according to a news release from the Australian National University.

“Identifying undescribed species and giving them official names goes a long way to making sure they’re properly looked after,” Emily Roycroft, author of a recently published Molecular Ecology study that documents the findings, said in the release.

After analyzing 111 tissue samples stored in museums, researchers concluded that the three species each occupy a distinct region of Australia. They were then named accordingly as the Pilbara or western delicate mouse, the eastern delicate mouse and the northern delicate mouse.

To the untrained eye, the trio of species are difficult to distinguish from each other, researchers said.

But they display a variety of subtle differences in body size and tail and fur coloration, according to the study.

Weighing as little as 6 grams, delicate mice are distinct from many other rodents that run rampant throughout the country, researchers said.

Unlike house mice and brown rats brought in during European colonization, delicate mice are native to Australia, where they have been living and evolving for the past 5 million years.

“They’re a crucial part of Australia’s natural environment and ecosystems,” Roycroft said in the release.

But because researchers were not aware of the three species until recently, much remains unknown about their statuses.

“We don’t know, for example, if population declines have gone undetected as a result of all three species being assessed as a single unit,” Roycroft said.

By splitting the mice into a trio of distinct species, researchers will now be able to reassess their populations and formulate a conservation plan.

This story was originally published February 23, 2024 at 2:09 PM with the headline "‘Delicate’ rodent species went undetected in Australia for millions of years — until now."