Ctenotus brooksi

Ctenotus brooksi, also commonly known as Brooks' wedge-snouted ctenotus, the wedgesnout ctenotus, and the sandhill ctenotus, is a species of skink found exclusively in Australia. This lizard inhabits the semi-arid regions of the continent, preferring desert sand ridge environments interspersed with vegetation, particularly areas containing spinifex.

Physical Characteristics

Ctenotus brooksi typically reaches a total length of 10–12 cm, with a snout-to-vent length (SVL) of approximately 5 cm. A notable feature of this species is the significant variation in its coloration and pattern, which is more pronounced than in other species within the Ctenotus genus. Its body color can range from fawn, orange, pink, to a reddish-brown, often transitioning to a more grey-green on the tail. The underside is typically a lighter shade. Some individuals may display a narrow, pale-edged black vertical stripe running from the nape to the tail, and may also have additional black stripes or dark flecks. A white mid-lateral stripe from the groin to the ear is present in some individuals.

Like other members of the Ctenotus genus, C. brooksi possesses smooth scales, well-developed limbs with five digits each, and ear openings equipped with anterior lobules. The lower eyelid is movable, though it lacks a transparent palpebral disc. These lizards are often referred to as "comb-eared skinks" due to a characteristic row of small scales on the anterior edge of their ear.

Distribution and Habitat

The species is endemic to Australia, with populations found in south-eastern Western Australia, South Australia, the Northern Territory, south-western Queensland, north-western New South Wales (including Sturt National Park), and north-western Victoria. While its distribution is widespread, populations are believed to be isolated by areas of stony or clayey terrain. Ctenotus brooksi is specifically adapted to desert sand ridge habitats, favoring areas with loose sand and vegetation around dune crests, and is often restricted to habitats where spinifex grass (Triodia) is present.

Ecology and Behavior

Ctenotus brooksi is a diurnal species, meaning it is active during the day. It is known for being fast-moving but also elusive, making it rarely observed. Its diet is generalist, consisting of various insect prey such as ants, beetles, and bugs.

Reproduction

All species within the Ctenotus genus, including C. brooksi, are oviparous, reproducing by laying eggs. Egg-laying typically occurs between September and January, which is noted as being earlier than many other Ctenotus species. The average clutch size for C. brooksi is 2.2 eggs.

Conservation Status and Threats

On a global scale, Ctenotus brooksi is classified as 'Least Concern' on the IUCN Red List, reflecting its abundance and generally stable populations. However, it was listed as vulnerable by the New South Wales Government in 2004, indicating a risk of becoming endangered in that state if threatening factors are not managed. Key threats to the species include predation by feral cats and foxes, habitat degradation caused by grazing from introduced herbivores and stock trampling which alters soil structure and promotes weed invasion. Uncapped and abandoned mining shafts pose a direct hazard, and modeling suggests that climate change is expected to reduce the species' range size by 2050.

Taxonomy and Etymology

First described in 1933 by British herpetologist Loveridge as a subspecies, Sphenomorphus leae brooksi, it was named in honor of American ornithologist Winthrop Sprague Brooks, who collected reptiles in Western Australia between 1926 and 1927. Australian herpetologist Harold Cogger elevated the taxon to species status and assigned it to the genus Ctenotus in 1983. The genus Ctenotus is the largest reptile genus in Australia and contains 104 species, often presenting identification challenges.

Management in New South Wales

Given its vulnerable status in New South Wales, management strategies focus on identifying key conservation sites and implementing cost-effective actions. These include controlling feral goats, pigs, rabbits, foxes, and cats near dense populations, promoting livestock management that improves habitat, and conducting regular monitoring of ecological parameters. Efforts also involve determining population extent, identifying critical protection areas, developing optimal fire regimes, and researching the species' ecology and habitat requirements. Retention of spinifex and leaf litter is encouraged, with recovery efforts targeting specific populations over time, applying adaptive management strategies, and incorporating operational guidelines into fire management plans for national parks to protect the species from fire.