Diplodactylus intermedius

Diplodactylus intermedius: The Spiny-Tailed Gecko

Diplodactylus intermedius, commonly recognized as the eastern spiny-tailed gecko or southern spiny-tailed gecko, is a species of lizard belonging to the Diplodactylidae family. This reptile is endemic to semi-arid regions across Australia, inhabiting states such as New South Wales, the Northern Territory, South Australia, Victoria, and Western Australia. Its preferred environments include mallee shrubland, woodland, and grassland areas.

Physical Characteristics and Defense

Diplodactylus intermedius is notable for its size, being one of the larger gecko species found in Australia. It features a grey, patterned body contrasted by a pale belly. The species derives its common names from the two prominent rows of orange-brown spines running longitudinally along its back and tail. These spines, which become more pronounced towards the tail, serve as a significant defense mechanism. When threatened, the gecko can exude a harmless yet foul-smelling orange fluid from these tail spines, often directed at attackers.

Anatomically, Diplodactylus intermedius possesses strong limbs and body, with disced toe tips typical of most geckos. The head is oviform and convex, featuring a rounded snout and large eyes. Adults typically reach an average snout-to-vent length of 64 mm (2.5 inches). Sexual dimorphism is present, with females generally being larger than males, who also exhibit distinct hemipenal bulges.

Taxonomy and Etymology

The species was first identified by James Douglas Ogilby in 1892, who described it as Diplodactylus intermedius. The genus Strophurus, to which it belongs, is characterized by the spines found along the back and tail and comprises 20 species, all endemic to Australia. The genus name Strophurus translates to "turning tail" in Latin, while the specific epithet "intermedius" signifies its intermediate positioning within its genus.

Ecology and Behavior

Diplodactylus intermedius is a nocturnal and terrestrial species, meaning it is active at night and lives primarily on the ground. As an ectotherm, it thrives in warm, semi-arid habitats. During daylight hours, it seeks shelter under rocks, tree bark, or within fallen logs, and can also be found in spinifex grass. Its activity at night is dedicated to hunting for food.

Diet and Reproduction

The diet of Diplodactylus intermedius is exclusively composed of arthropods. This includes a variety of invertebrates such as spiders, centipedes, scorpions, cockroaches, crickets, and beetles. Females begin reproducing around two years of age and typically lay a clutch of two eggs during the summer months. The incubation period for these eggs is approximately 45 days. Both males and females reach sexual maturity at the same age of two years.

Predators and Conservation

While the spiny defense mechanism is effective, predators such as birds are known targets for the defensive spray. Introduced species, like feral cats, also pose a threat to Diplodactylus intermedius populations, particularly in central Australia where they are known to prey on reptiles. Despite these threats, the species is not considered endangered. It has been assessed by the IUCN Red List of Threatened Species and is categorized as 'Least Concern', indicating a stable and widespread population.