Karyotypic Studies on Cyclorana and Associated Genera of Australian Frogs.

The taxonomic relationships of frogs from the genus Cyclorana are uncertain, for they share similarities with both the Leptodactylidae and the Hylidae. Karyotypic comparisons were made between seven species of Cyclorana and three species from the leptodactylid genera Notaden, Neobatrachus and Heleioporus. All Cyclorana species have 2n = 26, whereas the other species have 2n = 24. The position and type of secondary constrictions subdivide the species of Cyclorana into three groups. The similarity of chromosome morphology in these three groups with that of hylids suggests a close phylogenetic relationship. The major chromosome differences between Cyclorana and representatives from the leptodactylid genera suggests a fundamental dichotomy masked by adaptation to a fossorial mode of life.