Uncovering the mysteries of some of Australia’s least known reptiles

The Kimberley region of Australia is home to a huge diversity of plant and animal life. Reptiles are no exception with high diversity and endemism across the region. The Kimberley is also still full of mystery and new discoveries to be made, with species as large and spectacular the Limestone Velvet Gecko (Oedura murrumanu) being named to science as recently as 2014. In an attempt to learn more about the biodiversity of this region, some of the Herpetology Team of the Australian Museum undertook a two-week expedition in early September. With a particular focus on learning more about cryptic and poorly-understood snakes and lizards, the team was successful in targeting and locating rare and common species alike. Of high priority was the enigmatic and highly camouflaged Hidden Dragon (Cryptagama aurita) and the isolated and secretive Ord River Snake (Suta ordensis). Gathering more knowledge about these extremely cryptic animals is vital to our future understanding and ability to conserve them.

The Hidden Dragon (Cryptagama aurita) has a name excellently suited to what we know about it. First discovered in 1979 in two locations near Halls Creek Western Australia (WA), it was found again a few years later, in 1984 in the adjacent Northern Territory (NT). Following this, herpetologists fruitlessly surveyed for this species in an effort to learn more about it; and for 27 years they failed. However, in 2011, when a botanist conducting flora surveys happened upon and photographed this elusive lizard it sparked further intrigue, but further surveys still failed to find more lizards. Then in 2016, Stephen Mahony found several Hidden Dragons. In September, as part of the Australian Museum herpetology team, Stephen returned to the site to better understand this highly cryptic lizard that had managed to avoid scientific detection for such a long period of time. Over a two-week period, he and the team managed to find six Hidden Dragons, including both males and females, whilst also gathering information about their habitat, ecology, breeding biology, and diet. Genetic material was also collected to better understand them in the future.

Another resident of the east Kimberley that was of particular focus was the Ord River Snake (Suta ordensis). Like the Hidden Dragon, this species was detected in the 1980s and described to science in 1984. However, the Ord River Snake hasn’t remained quite as hidden, with several being sporadically found across sites in WA and the NT through to the 1990s. A significant part of what was lacking in the understanding of the Ord River Snake was its relationships to other species of Suta, its natural history, and how it had evolved. To do this, we needed genetic material! The herpetology team was lucky to encounter a single Ord River Snake, which allowed the team to collect some of the only live photos of the species and the first collection of genetic material. The team will now look at analysing the DNA of this species in the lab to better understand its relationships within the Suta group and its place within the larger elapid family.

As well as targeting some of the least-known and most poorly-understood denizens of the Kimberley, the herpetology team undertook general surveys of the region. The surveys resulted in us finding 37 other reptile species, along with several frog species still present around creeks despite the dry time of year. These included spectacular animals such as the Pygmy Mulga Snake (Pseudechis weigeli), many dragon lizards including the Slater’s Ring-tailed Dragon (Ctenophorus slateri) and numerous gecko species like the Sandplain Gecko (Lucasium stenodactylus). Collecting data from these better-known species is still vital as many are currently widespread but potentially harboring ‘cryptic species’. Cryptic speciation refers to a species that is currently regarded as geographically and ecologically widespread but is in fact several morphologically similar species each with a smaller distribution.

Overall this trip was a great success for the herpetology team, allowing it to collect vital data from two of Australia’s least-known reptile species. The collection of genetic material and other data from 28 species across the Kimberley region will be vital in uncovering the relationships of these species and identifying undescribed but highly similar species across this vast and beautiful region.

Stephen Mahony, Herpetological Technical Officer, AMRI