Conservation genetics of the endangered grassland earless dragon Tympanocryptis pinguicolla (Reptilia: Agamidae) in Southeastern Australia

The grassland earless dragon, Tympanocryptis pinguicolla, is listed as endangered throughout its range. A recent taxonomic study based on both morphological and allozyme data elevated pinguicolla from a subspecies of T. lineata to full species status, but the allozyme data showed considerable differentiation among pinguicolla populations. To investigate the magnitude and nature of these differences with an independent data set, we targeted key pinguicolla populations and sequenced an approximately 900 base pair DNA fragment of the mitochondrial genome that includes half of the ND4 gene and three tRNA genes. We obtained sequence data from 21 individuals drawn from the three T. pinguicolla populations, included representatives of two other Tympanocryptis species and used an Amphibolous species as an outgroup. Seven mitochondrial haplotypes were found among the 21 T. pinguicolla samples - two in the Australian Capital Territory (ACT) and five in the Cooma region, Phylogenetic signal in the data sets was extremely strong and a variety of phylogenetic analyses of the data all resulted in the same single fully resolved tree. There are 37 unique differences in the ND4 gene between the ACT and Cooma populations. This translates into genetic differences of between 5.76% and 6.23% between the two populations. In comparison to studies on other reptile groups in which the same fragment of DNA was used, the differences found between the ACT and Cooma populations are more in line with species-level differences than differences within a single species and suggests that these populations should be considered separate taxonomic units.