In the last remaining pockets of natural grassland in southeastern Australia lives a lizard so small it can hide in spider burrows. Inside the burrows, the grassland earless dragon, which weighs barely more than a quarter, finds shelter from the extreme temperatures found on the plains.
The grassland earless dragon, which gets its name from its scale-covered ears, is very hard to find because of its reclusive lifestyle and camouflaged appearance, says ecologist Will Osborne of Australia’s University of Canberra. So difficult to find, in fact, that the lizard went undocumented for about 30 years until Osborne and his colleagues rediscovered it in 1991.
It turns out that what scientists long thought was a single, elusive species of lizard living in southeastern Australia may in fact be several different species. A new analysis of the anatomy and DNA of dragons from different locations across the region, published today in the journal Royal Society Open Science, suggests that the isolated populations are distinct from each other.
“They look very, very similar,” says taxonomist Jane Melville of the Museum Victoria, lead author of the study, “but there are clear differences in the types of scales on their back and the shape of their skulls.” (Read about how poachers sometimes use scientific reports as maps to track and catch freshly discovered species.)
The study for the first time defines four species of grassland earless dragons. Of these, one—the Victorian grassland earless dragon—has not been reliably observed in the wild since 1969. The dragon was originally found near Melbourne in the 1940s but, “unfortunately,” says Melville, “many of the locations at which they were found are now in inner city Melbourne, while others have been converted to agricultural land.”
The Victorian grassland earless dragon is “very likely extinct,” says Osborne. He says that recent surveys of potential habitats have so far come up short. If extinct, the Victorian grassland earless dragon would be the first reptile species from mainland Australia to have gone extinct in modern times.
Nonetheless, Osborne says it’s too soon to stop looking. (See the world's largest bee, filmed for the first time in the wild after being presumed extinct.)
“Not all potential habitat has been surveyed yet, so this should really urgently be done before any more grassland disappears.” He adds that ideally, the remaining pockets of grassland should be protected from further conversion to agricultural fields, pastures or housing developments.
“Even if it turns out the [Victorian grassland] earless dragons are gone, there are still many other species that depend on these increasingly rare habitats.
For the three other newly defined species of grassland earless dragon, the new study will help to set up new breeding programs and expand existing ones, says Jane Melville. “These lizards may look really similar, but when we look at their genome, they are very different.” Their genes could turn out to be incompatible if crossbred, she says.
Fortunately for the dragons, no hybrids had been bred to date.