Genetic variation of blue-tongue skinks of the genus Tiliqua (Squamata: Scincidae) from New Guinea and Wallacea
Abstract
Populations of blue-tongue skinks inhabiting eastern Wallacea and New Guinea are traditionally assigned to either Tiliqua gigas, which is endemic to this area, or to Tiliqua scincoides that extends its range from the Australian continent. Despite a wide morphological variation among local populations, genetic data from non-Australian populations were almost absent.
We examined 128 specimens and sequenced mitochondrial ND4, 12rRNA and nuclear cmos genes. A phylogenetic analysis revealed the presence of two main clades corresponding to species Tiliqua scincoides and Tiliqua gigas.
We provide the first report of Tiliqua scincoides from the Aru Island and confirm that it is genetically related to the Tanimbar populations reported as Tiliqua scincoides chimaerea. The other samples belonged to Tiliqua gigas, which also shows a distinct phylogenetic structure congruent with the geographic origin of the samples.
The main split conforms to the north-south pattern of genetic variation, which was also reported in other animal species in New Guinea. (1) Samples from the northern coast of Irian Jaya, Seram, and Kai Islands belong to a distinct clade, which further splits supporting the recognition of the Tiliqua gigas keyensis subspecies. (2) Samples from the Bird's Head and southern coast of the Irian Jaya and Halmahera Island form the other clade within Tiliqua gigas, in which the Halmahera samples formed a shallow, but clearly distinct branch. The haplotype network analysis of mitochondrial ND4 gene in Tiliqua gigas samples suggests a strong differentiation among major population groups.