Carinascincus metallicus (O'Shaughnessy, 1874)

Common and Scientific Name

The Metallic Skink, scientifically Carinascincus metallicus, shows a range of colour variations that depend on its habitat.

Dorsal Coloration

It is typically brown with pale or dark streaks, which sometimes form distinct longitudinal stripes along its body. Its dorsal scales have a metallic sheen, which is the source of the species' common name.

Underside Coloration

The underside is usually grey or white with dark spots on the throat, chest, and tail, while the belly and lower tail often have an orange or pink hue.

Scale Characteristics

This species has 24–28 rows of keeled, or ridged, scales at mid-body.

Head Features

It has dark eyes, a movable lower eyelid with a transparent disc, and an ear opening of similar size.

Adult Body Length

Adult Metallic Skinks can grow up to 63 mm in length.

Geographic Range

The Metallic Skink is primarily found in Tasmania, and has more recently expanded into southern Victoria.

Habitats Occupied

It occupies a wide range of habitats, including coastal dunes, heathlands, dry and wet sclerophyll forests, and woodlands. It is most common in cool-temperate zones.

Thermoregulation

As a diurnal heliotherm, C. metallicus relies on external heat sources such as sunlight to regulate its body temperature.

Basking and Locomotion

It is primarily ground-dwelling, but often climbs rocks and fallen logs to bask.

Shelter Sites

During inactive periods, it shelters beneath rocks or in decomposing logs.

Elevation Range

The species occurs across a significant elevation range, from sea level up to 1500 metres, which reaches the subalpine tree line.

High Altitude Selective Pressure

At higher altitudes, colder conditions shorten the active season and limit basking opportunities, which exerts strong selective pressure on the species' thermoregulatory behaviour.

Reproductive Mode

The Metallic Skink is viviparous, meaning it gives birth to live young rather than laying eggs.

Mating Period

Mating occurs in autumn from March to May, with some late mating taking place in spring from September to November.

Copulation Trait

Males leave bite marks on the upper left chest of females during copulation.

Sperm Storage and Fertilisation

Females store sperm over winter from June to August while in brumation, and ovulation and fertilisation occur the following spring.

Gestation and Offspring Count

Gestation lasts approximately 18 weeks, after which females give birth to 1–8 offspring in summer or early autumn.

Embryonic Nutrition Source

While some nutrients are transferred to embryos through the placenta, most embryonic nutrition comes from the large yolk mass.

Thermal Effects on Offspring

Thermal conditions during embryonic development influence birth timing, size, mobility, and behaviour, which in turn affect offspring fitness.

Maternal Thermoregulation Benefit

Because C. metallicus gives birth to live young, females can regulate embryonic temperature by adjusting their basking behaviour, reducing exposure to harmful temperature extremes.

Thermoregulation Survival Advantage

This thermoregulatory flexibility may shape offspring traits, enhancing survival in specific environmental conditions.