A Phylogeny for Australian Chelid Turtles Based on Allozyme Electrophoresis

Abstract

Allozyme electrophoresis was used to explore relationships among the Australian Chelidae in order to test the currently accepted phylogeny and to determine the affinities of several distinctive but undescribed species. The data set was comprehensive, being based on 54 loci for turtles from 76 populations of 22 species (excluding Pseudemydura umbrina and Chelodina novaeguineae). Analysis by both phenetic and phylogenetic methods revealed that the genus Elseya, as currently recognised, is paraphyletic. The closest common ancestor to species of Elseya has Emydura (and possibly Rheodytes) among its living descendants. Five clades among the short-necked taxa were considered distinctive enough to warrant recognition at the generic level, namely (1) Emydura, (2) Elseya (to include only El. novaeguineae, El. dentata and three related but undescribed taxa), (3) Rheodytes, (4) the El. latisternum group (to include El. latisternum and three related but undescribed taxa), and (5) 'short-necked alpha', an undescribed species with no clear affinities. Levels of divergence among these generic groups were similar to levels of divergence among genera of cryptodiran turtles. A phylogeny for the Australian Chelidae, incorporating the results of the allozyme analyses, is presented. Further work is required to firmly establish the affinities of Rheodytes and 'short-necked alpha' in a phylogeny for the Australian chelid turtles.