Australia has added two ‘new’ marsupials to its books, with scientists working the Pilbara region of Western Australia finding two unique species of the nation’s smallest native mammals.
Until this week, five planigale species across Australia and New Guinea had been discovered (though ‘described’ is a more accurate term). Now, a team of researchers from QUT and the Western Australian Museum have closely studied record specimens to decide there are actually seven.
The cracking-clay Pilbara planigale (Planigale tealei) and orange-headed Pilbara planigale (P. kendricki), now described in the journal Zootaxa, might appear like other species to the naked eye, but their differences are more than skin deep.
“When specimens are collected, often they will take a genetic sample from them at the time, or they’ll take genetic samples and release animals in the wild as well,” says Dr Linette Umbrello, a researcher at QUT who is based at the WA Museum.
“They might take a piece of the ear, take a little clip off the ear, and we can use that for genetic analysis.”
Umbrello and her colleagues study the genomic information of planigale specimens and compare them to the genomes of others. Significant differences in DNA indicate a particular individual might belong to a different or previously undescribed species.
Once a new species is genomically spotted, its physical traits – morphology – are studied. This helps field scientists to more easily distinguish species from one another without the time-consuming nature of genetic sampling.
Between these two Pilbara inhabitants, the orange-headed variety weigh 7-12 grams and are found in rocky and sandy soils. The cracking-clay planigale is named for its habitat and is half as heavy.
These newly-described species are also restricted to the Pilbara region. Among the others are the common planigale (P. maculata) and the long-tailed planigale (P. ingrami). However, these are actually ‘species complexes’ – groupings of organisms that are so morphologically similar that it is unclear whether it is truly a single species, or conceals many others.
Umbrello expects genetic sampling will grow the number of known planigales in years to come.
“These two are the first cab off the rank,” Umbrello says.
“But the DNA sequence data [of the common and long-tailed planigale] is suggesting there’s actually multiple evolutionary lineages within that group.
“That suggests it’s actually probably multiple species, but someone now has to look at the specimens and see if they can be identified as separate forms.”