New Wallaby Species Discovered Hiding in Plain Sight

Wallabies are only natively found in one continent in all the world: Australia. And even as some wallaby species are disappearing from Down Under, others are just being discovered. Such is the case for the common short-eared rock-wallaby (Petrogale brachyotis), which may actually be two distinct species.

Rock-wallabies (genus Petrogale) actually represent one of the largest groups of extant macropods in all of Australia, easily outnumbering even the iconic kangaroo. They inhabit rocky regions such as cliffs, gorges, and even quarries, and are relatively difficult to spot thanks to their small size (ranging from 2 to 26 lbs).

Most wallabies look very similar as well, resembling a marriage between a rabbit and a tiny kangaroo. This has led to earlier scientists lumping the widespread rock-wallabies into one group. However, new DNA evidence indicates that Northwest and Northeast groups are genetically distinct from one another, explaining for their subtle differences in coloration and size.

Namely, wallabies from the eastern Northern Territory are traditionally small (~6 lbs) and darkly colored, accented with distinct head and side stripes and brightly colored limbs. Western Northern Territory wallabies, on the other hand, can be nearly twice as large with lighter fur but less prominent markings. These subtle differences in appearance may also mean differences in behavior during mating or even foraging.

"Our study has shown that the Top End (western) and Kimberley (eastern) rock-wallaby populations are genetically and morphologically distinct and should be regarded as separate species," researcher Sally Potter, from the Australian Museum Research Institute and the Australian National University, recently told Sci-News.

"The newly recognized species will be known as Wilkins' Rock-wallaby or the Eastern Short-eared Rock-wallaby (Petrogale wilkinsi)," she added in a museum statement. "The species is named after Australian explorer, naturalist and aviator Capt Sir G. H. Wilkins who, in 1925, collected one of the first specimens of this species in southwestern Arnhem Land."

Potter and her colleagues added that this is but another example of how little we actually know about mammal progression and evolution, where even two remarkably similar species can be exceptionally different on a genetic level.

"Even amongst relatively well studied and high profile groups such as mammals, new species await discovery," the researchers said.

These results were published in the Australian Journal of Zoology earlier this week.

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