Morethia adelaidensis

Saltbush Skink (Morethia adelaidensis)

The saltbush skink, scientifically known as Morethia adelaidensis, is a small lizard species endemic to Australia. Belonging to the genus Morethia, which comprises eight species all found exclusively in Australia, this skink is characterized by its transparent eye discs, stationary eyelids, and specialized limbs that facilitate rapid movement across sand dunes.

Distribution and Habitat

This species is found across a wide range in Australia, from the Lake Eyre Basin to the Nullarbor coastal regions, and extends into the arid zones of Western Australia and the northern border of New South Wales. Saltbush skinks primarily inhabit arid shrublands, with their distribution closely linked to the presence of saltbush chenopod shrubs. While they are often found in areas with observable grass cover, such as temperate native grasslands in South Australia, they also occupy river gorges and rocky granite outcrops, though their arid distribution is not strictly limited to these specific environments.

Physical Characteristics

Adult saltbush skinks are small, with males averaging approximately 5 centimeters in snout-vent length. Their coloration is typically grey or olive grey, marked by two prominent black bands running dorsally and laterally down to the tail. The upper black band is notably darker and features speckled patterns. Below these black bands, a single, interrupted white band extends through the ear region and above each forelimb. While most populations exhibit darker markings, individuals found in the Lake Eyre region may display paler coloration and less distinct lateral black lines. Anatomically, they possess visibly separated nasal superiors and their eyes are encircled by clusters of granule-like scales.

Diet and Behavior

As insectivores, saltbush skinks, like other members of the Morethia genus, feed primarily on insects. They are diurnal, meaning they are most active during daylight hours, and like all reptiles, they rely on external heat sources for thermoregulation. A notable characteristic of this species is its halophytic nature, demonstrating a high tolerance for saline environments. Saltbush skinks also exhibit burrowing behavior, creating shallow depressions in sandy soils, often found among shrubs or rocky outcrops.

Reproduction and Social Behavior

Saltbush skinks reproduce by laying eggs, a characteristic known as being oviparous. Each breeding female typically lays clutches averaging around five eggs, which are usually deposited in sandy substrates or within rocky formations. The size of the clutch is often influenced by the size of the female. During the breeding season, males develop distinctive orange 'fire-tail' markings along their ventral edges, extending under the tail and around their limbs, which are believed to serve a territorial purpose. While detailed breeding observations are limited, anecdotal evidence suggests that communal nesting may occur, with multiple females potentially nesting together.

Conservation and Predators

The International Union for Conservation of Nature (IUCN) currently classifies the saltbush skink as 'Least Concern.' This designation indicates that the species is not currently facing significant threats from general land clearing or grazing activities. However, like many smaller skink species, they are subject to predation by native snakes, including species from the Elapidae genus. Curl snakes (Suta suta) have been documented to prey on saltbush skinks in Western Australia, along with other medium to large snake species that consume smaller reptiles.