Saltuarius salebrosus, also known as the rough-throated leaf-tailed gecko or Central Queensland leaf-tailed gecko, is a gecko found in Australia. It is endemic to dry areas in mid-eastern and south-central Queensland.
Saltuarius salebrosus, commonly called the rough-throated leaf-tailed gecko, is a species of gecko belonging to the genus Saltuarius which translates to the "keeper of the forest". The genus Saltuarius was established in 1993 to accommodate a monophyletic group of larger species of geckos with unique interior and exterior morphological characteristics and a distinctly different chromosome number to Phyllurus. The genus Saltuarius is a long, self-sufficient, evolutionary lineage of leaf-tailed geckos, described as an innocuous, moderately sized species. Geckos are an ancient taxon of primarily nocturnal lizards, exhibiting great diversity and a worldwide distribution, occupying a wide variety of habitats and external conditions. Rough-throated leaf-tailed geckos are a group of the Carphodactylidae geckos of rainforests and rocky habitats of eastern Australia.
The species was first described by herpetologist Jeanette Covacevich in 1975. The rough-throated leaf-tailed gecko is the largest of the Australian geckos, with a snout-length up to 145 mm and a total length of 250 mm. It may be distinguished by its exceedingly tubercular throat and is primarily a cavernicolous or rock-dwelling species, found in a variety of habitats ranging from gully rainforest to drier rocky scrublands. It is native to Australia and is found mostly in ranges west and south-west of Rockhampton, Queensland. The rough-throated leaf-tailed gecko average life span of seven to nine years in the wild, with a captivity life span that ranges from ten to twenty years.
Taxonomy The species Saltuarius salebrosus was first described by Jeanette Covacevich in 1975 and it was originally placed under the genus Phyllurus and called Phyllurus salebrosus. This was later revised as a result of work published by Bauer in 1990 which examined the skeletal structure of the geckos within the Phyllurus genus. He composed a set of classification characteristics including differences in cartilage formation which allowed for reclassification and noted two distinct sub-groups within the Phyllurus genus. A new genus was formed and coined Saltuarius which this gecko was then placed under, giving it its current name Saltuarius salebrosus.
The work by Bauer in 1990 was further expanded upon by Covacevich, Couper and Moritz and published in 1993. This research employed the discipline of karyology and looked at genomic and characteristic features that distinguish the Phyllurus and Saltuarius groups. In these groups there are notable differences in the structure of the interclavicle bone. Species in the Saltuarius genus were found to have more chromosomes than those in Phyllurus which gave evidence for these groups coming from different evolutionary branches. This allowed for a new genus Saltuarius to be coined.
Members of the Phyllurus genus were then recategorized and the new genus Saltuarius was at first found to include three other species in addition to Saltuarius salebrosus. These are the Saltuarius cornutus which was first described by Ogilby in 1892, Saltuarius wyberba first described by Couper and colleagues in 1997, and Saltuaris swami first described by Wells and Wellington in 1985. Later two additional species were added to this genus, Saltuarius orraya as first described by Couper and colleagues in 2000 and Saltuarius kateae which was first described by Couper and colleagues in 2008.
Description Saltuarius salebrosus is a relatively large genus of Australian gecko and has an average nose to tail (or snout to vent) length of 14–16 cm. It is distinguishable from the other members of its genus because of its uniquely shaped tail from which it gains its colloquial name the rough-throated leaf-tailed gecko or Central Queensland leaf-tailed gecko. The tail has a flat and wide heart shape with spines present on the tip. These spines are less common with tails that have been regrown following the original tail’s severance. The tail is also mottled with patches of lighter colour which often join to form cross lines. Nearly 50% of adults have regenerated tails as it is quite easy for this species to drop their original tail.
The throat of Saltuarius salebrosus is covered with small protrusions known as tubercles which give it its distinctive rough textured throat. These tubercules are formed from excess skin tissue and distinguish this species from its close relative Phyllurus cornutus whose throat is relatively smooth.
The underbelly of Saltuarius salebrosus is whiteish in colour and within a skin-fold towards its legs are a set of curved spines which protrude from a cluster of scales which are larger than those seen on the rest of the body. In the males only there are pre-anal pores adjacent to these spines. The scales on the backside of this species are generally “small, flat, granular”, and are interspersed with rosettes of larger scales with a tubercule at their centre like those found on its throat. This species has 5 digits on each foot from each of which a claw protrudes. Saltuarius salebrosus is distinguishable from other members of the Saltuarius genus by its colouration and markings. The body of this species is usually brown or olive green in colour and covered in patches of lighter colour which are outlined by a thick black to brown border. Along the back of this gecko there are usually four or five of these patches, while the rest of the body is irregularly scattered with additional markings and the head usually has "two or more W-or M-shaped dark brown markings and irregular lines and reticulations". Strong horizontal lines are apparent on the legs of this species and its toes are a lighter shade to its foreleg. In these ways it is distinguishable from another member of its genus Saltuarius jackyae, which does not have the prominent body outlines or cross-lines on its legs. The unique patterning of this species allows them to camouflage against different surfaces in their environment, such as rocks and trees.
Biology Saltuarius salebrosus is identifiable by its exceedingly tubercular throat and the longer spinous tip of original tails, known to be similar to Phyllurus cornutus (northern leaf-tailed geckos). Saltuarius salebrosus can be distinguished from Phyllurus cornutus by its chin scalation, as rough-throated leaf-tailed geckos are rough covered with raised tubercules, whereas S. cornutus is smooth with no raised tubercules. With the snout to vent length at 14 cm, rough-throated leaf-tailed geckos are one of Australia’s largest 112 described species of geckos. Saltuarius salebrosus can be identified by its large, triangular, flat head with a strongly depressed body. The skin of the rough-throated leaf-tailed geckos exhibits small, hair-like microstructures called spines, which vary in length from 0.30 to 3 micrometres among species. The rough-throated leaf-tailed gecko’s colouring is usually in various shades or brown or green with a mottling that looks similar to lichen. This makes it very difficult to distinguish from the trees that the geckos live in. The gecko’s original tail is a flat, fleshy, appendage and ornamented with colours and textural tubercules and spines. In the event that the tail is lost, it regrows, the new tail will be broader and flatter with different coloration, and a shorter tip.
Reproduction Like other members of the reptile class, Saltuarius salebrosus reproduces by oviparous means. It has a clutch size of 2 meaning it releases 2 eggs per breeding event. These eggs have a soft shell, and their incubation period is estimated to be approximately 103 days. Hatchlings of this species are at this point assumed to have a similar size to those of a closely related species the Saltuarius cornutus, with a nose to tail length of 50.63 – 51.41 mm.
Reproduction under oviparous represents the ancestral mode of reproduction in reptiles. Oviparity reptile eggs are laid quite early, and the embryos are relatively undeveloped. While rough-throated leaf-tailed gecko can produce 2–3 clutches during breeding season, they are unable to reproduce in cold climates due to low temperatures which prevent the eggs from developing. It is important that plenty of calcium and vitamin D3 is provided during this process, to allow for proper bone development during the growth of hatchlings and juveniles.
This process includes the female gecko digging a nest into the soil at little depth under the litter of the forest, laying two eggs and the covering the eggs with dirt and leaves. After, the female places the eggs in the nest, limited parental care is shown, as eggs and hatchlings are left on their own. Each nest can contain up to 14 eggs from multiple females in a single communal nest, females will sometimes lay multiple clutches of eggs per season. Reproduction and the length of incubation period is closely related to the species Saltuarius cornutus, due to close taxonomic affinity.
Distribution and habitat
The thirteen named species of leaf-tailed geckos are all located along eastern Australia between Sydney and Cape York Peninsula as an obligatory rainforest species. Due to the governments ban on exports of reptiles from Australia since 1960s, the gecko family is endemic to the continental Australia. Leaf-tailed geckos are mainly associated with tropical and subtropical rainforests, with the minority located on heaths on sandstones and granites in Eastern Australia. Leaf-tailed geckos are confined to Eastern Australia, with a highly localised distribution with only two sites having more than one-leaf tailed gecko species. Rough-throated leaf-tailed geckos are the most widespread of the leaf-tail geckos in rainforests and rocky habitats of mid-eastern Queensland. This species of the rough-throated leaf-tail gecko is endemic to dry areas in Mid-eastern and Southern Queensland, Australia.
It is primarily a cavernicolous rock-dwelling species, that is found in a variety of habitats ranging from gully rainforests to drier rocky scrublands. Within these environments it shows a preference for sandstone outcrops and open forest environments. It is commonly found in areas ranging between west and south-west of Rockhampton, Queensland, including the Blackdown Tableland and Dawes Ranges areas.
Additionally, this species has a tendency to live in dispersed clusters as highly localised communities. The "Many Peaks Range" (24°31'S, 151°29'E), which this species is known to inhabit is the only known location that supports more than one species of leaf tailed gecko. This area is also home to the Phyllus Caudiannulatus.
Behaviour