A taxonomic review of the genus Microacontias (Scincidae: Acontiinae) based on DNA and morphological data
Janse van Vuuren, Lucas Cornelius
MetadataShow full item record
The recent taxonomic review of the legless, fossorial skink genus Acontias by Daniels et al. (2006), using DNA sequence data, led to the erecting of the new genus Microacontias for all the small-bodied taxa. These are Microacontias lineatus lineatus, Microacontias lineatus tristis, Microacontias lineatus grayi and Microacontias litoralis. The latter species was, however, nested in the lineatus complex which raised questions about its true taxonomic status. Furthermore, the taxonomic status of the lineatus complex is questioned following the poor relationships between taxonomic diversity and morphological character states in these sub-terrestrial skinks (Daniels et al., 2002, 2005, and 2006). This study therefore addresses the following two questions: (i) should the taxonomic status of the lineatus complex be accepted as it stands and (ii) is Microacontias litoralis an independent species or does it form part of the lineatus complex. It is hypothesized that M. l. lineatus and M. l. tristis do not represent separate taxa (near identical morphology), while M. l. grayi and M. litoralis should be given independent status. The diagnostic methods utilized were (i) Mitochondrial DNA (mtDNA) sequence data (16S rRNA and Cytochrome b), (ii) morphometric data comprising head and body measurements, and (iii) meristic data comprised of various scale counts. The findings suggest that at least in terms of the gene fragments sequenced, the subspecies of the lineatus complex are very closely related. The phylogeny reports no distinct grouping of the taxa, nor could the morphological analyses separate the taxa as independent evolutionary units. The low genetic divergence but extensive color variation can be viewed as an example of morphological diversification despite genetic conservatism.