|The Gulbaru leaf-tailed gecko is endemic to Patterson Gorge in the Paluma Range of northeast Queensland, Australia. This nocturnal, carnivorous hunter is notable for its effective camouflage. Despite its name, it does not have a flattened, leaf-shaped tail, but does have the ability to regenerate it.|
The Gulbaru leaf-tailed gecko is narrow and cylindrical and separated from other Phyllurus species by having a partially divided, as opposed to fully divided, rostral scale. The rostral scale is partly divided by a midline groove. There are deep, vertical grooves partially dividing the rostral scale. The rostral is not in contact with the nostril. There are 6-7 scales along the dorsal margin of the rostral shield.
Gulbaru leaf-tailed geckos are small in body length at 89 millimeters long. Measurements have been taken using Mitutoyo electronic callipers. Additional measurements have been taken in the field in December 2001 of 4 males and 3 females.
The Gulbaru leaf-tailed gecko has a large, depressed, triangular head that is distinct from the neck. It is covered in very small granules with larger pale conical tubercles at the back and sides. The skin of the head is co-ossified with the skull.
The Gulbaru leaf-tailed gecko’s ear opening is elliptical and vertical and are much less than half as large as the eye. There are raised projection overhangs on the upper margin of the ear.
The Gulbaru leaf-tailed gecko’s dorsal base color is grey with irregular dark blotches on the head, body, and limbs. There are blotches on the body that tend to roughly align transversely or align along the dorsal mid-line.
The digits are strongly banded. The inner anterior digit has only slightly reduced pigment.
The body and limbs are ventrally off-white to immaculate cream with slight peppering on the chin and blotching ventrally on the upper forelimb. There are blotches aligned transversely on the limbs. The pectoral and postcloacal regions also have darker pigmentation. The labials are off-white and mottled with brown.
The original tail is dorsally grey, marked with irregular dark blotches showing some alignment along the mid-line. There are eight cream bands on the tail, but the second and fourth are poorly defined. Only the four bands on the attenuated portion extend to the ventral surface. The distal knob is white, ventrally cream, and peppered with brown specks. The regenerated tail lacks the cream bands, is dorsally grey, and mottled with irregular dark blotches. The ventral surface is similar, but with reduced pigmentation. There is a pair of large, dark and white blotches immediately anterior to the tail base.
Unlike most Phyllurus species, the Gulbaru leaf-tailed gecko does not have a very flattened, leaf-shaped tail. The possession of a cylindrical, non-depressed, tapering original and regenerated tail separates the Gulbaru leaf-tailed gecko from all congeners except the ringed thin-tail gecko Phyllurus caudiannulatus and the Oakview leaf-tailed gecko Phyllurus kabikabi.
Rarely seen outside their native habitat, Gulbaru leaf-tailed geckos are notable for their highly effective camouflage which is in part aided by the spiny tubercles that cover every body part. There are small tubercles on the Gulbaru leaf-tailed gecko’s body with larger tubercles on the base and sides of the tail. The very small spinose body tubercles of the Gulbaru leaf-tailed gecko are in marked contrast to the large spinose body scales of the ringed thin-tail gecko Phyllurus caudiannulatus.
The Gulbaru leaf-tailed gecko was named after the Aboriginal name for the Paluma Range, “Gulbaru”.
The epithet is to be treated as a noun in apposition.
The Gulbaru leaf-tailed gecko has no recognized subspecies.
The Gulbaru leaf-tailed gecko is a highly distinct species of leaf-tailed gecko in the small genus of Australian leaf-tailed geckos, Phyllurus. Mitochondrial DNA sequencing allows the phylogeny to be revised to include this species.
Some of these species, suhc as the northern leaf-tailed gecko (Saltuarius cornutus), have recently been reassigned to the genus Saltuarius. A phylogeny of the leaf-tailed geckos showed Saltuarius and Phyllurus to be monophyletic groups. The long-necked Northern leaf-tailed gecko (Saltuarius occultus) from the McIlwraith Range was recognized as a deeply divergent lineage basal to Saltuarius and Phyllurus. Re-evaluation of the morphological data, combined with new molecular information, resulted in reassignment of this species at the generic level: Orraya occultus. The molecular data showed the leaf-tail geckos to represent ancient lineages, with the split between Saltuarius and Phyllurus dated at c. 58–74 million years ago and the divergence among species in the mid-east Queensland (MEQ) clade of Phyllurus being c. 31–38 million years ago. Thus it was postulated that the MEQ Phyllurus represent the relictual distribution of an ancient group separated by pre-Pleistocene contraction of rainforest.
The Phyllurus geckos resemble the Uroplatus geckos of Madagascar. This is an example of convergent evolution because they are not closely related.
An analysis of 729 bp of mitochondrial 12S rRNA and cytochrome b genes reveals the Gulbaru leaf-tailed gecko to be a deeply divergent lineage with closer affinities to mid-east Queensland congeners than the geographically neighboring Mount Elliot leaf-tailed gecko (Phyllurus amnicola) on Mount Elliot.
The Gulbaru leaf-tailed gecko is the most northerly member of the genus Phyllurus.
This gecko is endemic to Patterson Gorge in the extreme southern Paluma Range of northeast Queensland, Australia, 37 kilometers northwest of Townsville. Individuals have been collected at Palm Tree Creek (19°20′S, 146°28′E) and on an unnamed tributary of Black River (19°17′S, 146°29′E).
Surveys in the rainforest to the north and south of Patterson Gorge have failed to locate this species.
The estimated extent of occurrence (EOO) for this species has been calculated as 23 km², although this excluded areas between the localities with no suitable habitat, and its area of occupancy (AOO) as 14 km².
Extensive surveys in the southern Paluma Range of northeast Queensland has now identified six subpopulations, which are isolated from one another, all in the south Paluma Range west of Townsville. Most of the six localities are distant from one another and exhibit a degree of genetic divergence from one another.
A revised area of occupancy derived from these localities suggests the true area of occupancy may be 10-12 km².
There is no population information available for the Gulbaru leaf-tailed gecko.
Although the Gulbaru leaf-tailed gecko’s population trend is unknown, the extent and quality of habitat has declined at least at two localities.
The Gulbaru leaf-tailed gecko’s population is considered severely fragmented.
Densities vary between sites. In two localities the species is found at high densities, and at one very low density. Field surveys of Patterson Gorge and the adjacent ranges indicate that this species is restricted to a very small area of highly fragmented habitat, of which only a small proportion receives a degree of protection in State forest.
The Gulbaru leaf-tailed gecko is terrestrial.
The Gulbaru leaf-tailed gecko appears to be completely forest and rainforest dependent.
The Gulbaru leaf-tailed gecko inhabits subtropical/tropical moist lowland forests and seasonal/intermittent/irregular wetlands, such as rivers, streams, and creeks. It occupies steep rocky habitats inside rainforest.
Individuals have been collected from gullies of Hoop Pine (Araucaria cunninghamii)-dominated microphyll to notophyll vine forest and near running water and boulders in rainforest along drainage lines. Such gullies are set in a matrix of open Eucalyptus woodland.
Most individuals are found among boulders and rock fissures in close proximity to a stream. They are often seen head-down on vertical rock surfaces or foraging low on slender tree trunks.
The Gulbaru leaf-tailed gecko appears to be nocturnal. On surveys, all individuals have been found at night, activity beginning soon after dark. Leaf-tailed geckos tend to be nocturnal hunters, most actively searching the forest for food under the cover of night.
The Gulbaru leaf-tailed gecko has the ability to regenerate its tail.
Of 12 individuals, six male, five female, and one juvenile, encountered over two nights by a surveying team in 2003, 75% had regenerated tails. This is a similar proportion to that seen in the Mount Elliot leaf-tailed gecko (Phyllurus amnicola).
The Gulbaru leaf-tailed gecko is a carnivorous animal and the bulk of this lizard’s diet is primarily comprised of insects. They also hunt a number of other invertebrates along with the odd small rodents or reptile should it get the chance.
The Gulbaru leaf-tailed gecko is thought to have a similar reproductive strategy as the broad-tailed gecko (Phyllurus platurus). They are inferred to mate at least until autumn and that females store sperm through the winter.
In early March 2001, two sexually mature male Gulbaru leaf-tailed geckos were collected. They were in peak reproductive condition with turgid testes and sperm present in the epididymis, inferred from opacity.
The Gulbaru leaf-tailed gecko is oviparous and produces young by means of eggs that are hatched after they have been laid by the parent. Four gravid females encountered on December 3, 2001 each contained two shelled eggs. One female was collected and laid two oval-shaped eggs in captivity two weeks later. After incubation in vermiculite at 26°C for approximately 60 days the eggs failed. Fully formed embryos were found on dissection.
The Gulbaru leaf-tailed gecko is not currently found in trade but is desirable and might well be targeted by collectors.
The Gulbaru leaf-tailed gecko has been listed as Endangered because its estimated extent of occurrence is approximately 12 km², its distribution is severely fragmented, and there is a continuing decline in the extent and quality of its habitat as a result of burning and grazing.
The rainforest-dependent Gulbaru leaf-tailed gecko is threatened by unmanaged burning and grazing that is severely fragmenting and destroying the remaining forest.
This area would have had larger patches of dry rainforest prior to European settlement and remaining forest is now restricted to isolates, although genetic data suggests a degree of isolation dating back several thousand years. This is prime grazing land, and grazing and attendant fire has accelerated fragmentation.
There is ongoing, unchecked destruction of dry rainforest habitat by fire. Three of the known sites form a cluster near an area of farmland where locals set fires late in the dry season. This has led to hot, uncontrolled fires in recent years that are known to have destroyed rainforest in at least one locality.
The southernmost locality, which exhibits the lowest density and highest genetic divergence, is also likely to be at risk from fire.
Collection for the pet trade represents the only major threat to the remaining Gulbaru leaf-tailed gecko localities. While collection has not yet been reported, these sites are accessible and the species is desirable in trade.
Patterson Gorge is located just south of the Wet Tropics UNESCO World Heritage site boundary, and only a small fraction of the suitable habitat for the Gulbaru leaf-tailed gecko is protected by Mount Cataract State Forest. Part of the Gulbaru leaf-tailed gecko’s habitat is now protected within Paluma Range National Park, an extension in part motivated by the conservation requirements of this gecko.
The establishment and expansion of protected areas is recommended to reduce the rate of habitat loss occurring within the Gulbaru leaf-tailed gecko’s range.
Effective fire management is also recommended, especially in the south of the range.
Development of strategies to mitigate the risk from collection, including keeping the specific identity of localities secret, is another recommendation.
Targeted surveys of small, isolated rainforest patches along the Queensland coast coupled with detailed morphological and molecular studies have greatly advanced our knowledge of leaf-tailed geckos, such as the Gulbaru leaf-tailed geckos.