Wednesday, October 22, 2014

[Herpetology • 2014] Strophurus horneri | Arnhem Phasmid Gecko • A New Phasmid Gecko (Squamata: Diplodactylidae) from the Arnhem Plateau: more new Diversity in Rare Vertebrates from northern Australia

Arnhem Phasmid Gecko | Strophurus horneri  
Oliver & Parkin, 2014
FIGURE 4. A) Strophurus horneri sp. nov. seen and photographed in southern Kakadu National Park.
Note prehensile tail and pink tongue. Photograph: Brendan Schembri.
FIGURE 3. Strophurus horneri sp. nov. in life. Holotype NMVD72591 photographed at Yirrkakak.
Photograph: Rich Glor.
FIGURE 5. Habitat of Strophurus horneri sp. nov. at Namarragon Gorge, Kakadu National Park.
Photograph: Stuart Young.

The Arnhem Plateau is a rugged expanse of sandstone escarpment in the Australian Monsoonal Tropics with a highly endemic biota. Here we describe a new species of small spinifex dwelling Strophurus (phasmid gecko) that also appears to be endemic to this region. Strophurus horneri sp. nov. can be diagnosed from all congeners by aspects of size, coloration and scalation. Even with the description of this new species, however, levels of morphological and genetic diversity within Strophurus from the stone country of the Northern Territory suggest additional divergent lineages are present. A number of recent studies have now provided preliminary evidence of evolutionary diversity within the Arnhem Plateau, but data remains scant and almost nothing is known about how topography and historical processes have shaped the endemic biota of this region.

Keywords: Australian Monsoonal Tropics, endemism, lizard, Kakadu National Park, sandstone, spinifex

Distribution and habitat. Strophurus horneri sp. nov. is known only from the Arnhem Plateau region in the Top End of the Northern Territory. The holotype was collected on the northern edge of the Arnhem Plateau in the vicinity of Yirrkakak. Other specimens have been observed at other localities along the western edge of the Arnhem Plateau (Brendan Schembri, Mitchell Scott pers. comm.), and this species may occur throughout the western and northern Arnhem Plateau (Fig. 1). 
Where data is available, all specimens were found in well developed spinifex patches on or at the base of large sandstone escarpment or boulders (Fig. 5). The longitudinal striped patterning evident in life provides excellent camouflage in this habitat. Brendan Schembri (pers. comm.) reports that this species was comparatively easy to find in long unburnt spinifex in a sheltered gully in southern Kakadu. The potential role of fire frequency in shaping the distribution and abundance of this taxon warrants further investigation.

Etymology. Named in honor of Dr. Paul Horner, Emeritus Curator of the Museum and Art Gallery of the Northern Territory, in recognition of his significant contributions to Australian reptile systematics.

Oliver, Paul M. & Tom Parkin. 2014. A New Phasmid Gecko (Squamata: Diplodactylidae: Strophurus) from the Arnhem Plateau: more new Diversity in Rare Vertebrates from northern Australia. Zootaxa. 3878(1): 37–48.