Molecular phylogeny of viviparous Australian elapid snakes: affinities of Echiopsis atriceps (Storr, 1980) and Drysdalia coronata (Schlegel, 1837), with description of a new genus

The rare Australian venomous elapid snake 'Echiopsis' atriceps has been the subject of considerable taxonomic instability with the five known specimen s assigned to four genera by various authorities. Phylogenetic affinities o f the rare Elapognathus minor also are poorly understood and have been the subject of some disagreement. To examine the phylogenetic affinities of the se two rare taxa, a molecular data set comprising 1680 base pairs of mtDNA was assembled from a representative of each of the terrestrial Australian v iviparous elapid genera and two species of Drysdalia, a genus about which t here also has been phylogenetic controversy. A total of 936 base pairs of 1 2S rRNA, 454 base pairs of 16S rRNA and 290 base pairs of cytochrome b mtDN A were sequenced for 15 species. The Asian elapid Naja naja was used as the outgroup. These mtDNA regions provided 195, 38 and 72 parsimony informativ e sites, respectively, for a total of 315 parsimony informative characters. Unweighted phylogenetic analyses were performed under both parsimony and n eighbour-joining criteria. Parsimony analyses of the unweighted, combined d ata set resulted in a single fully resolved most parsimonious tree 1225 ste ps long. The neighbour-joining tree differed by only a single weakly suppor ted branch. These data strongly support a sister group relationship between 'Echiopsis' atriceps and the Australian broadheaded snakes of the genus Ho plocephalus with a bootstrap value of 99%. Templeton tests soundly reject a ll previous taxonomic arrangements for this species. Our data also strongly support a sister group relationship between Elapognathus minor and Drysdal ia coronata with a bootstrap value of 98%. Importantly, Drysdalia coronata and Drysdalia coronoides do not form a monophyletic group, supporting some previous studies. Based on our results, we allocate 'Echiopsis' atriceps to a new monotypic genus and re-describe Elapognathus to include 'Drysdalia c oronata.