Relations Among Ringtail Possums (Marsupialia, Pseudocheiridae) Based on Dna-Dna Hybridization

Abstract

Comparison among eight pseudocheirid species and two outgroup petaurids were made by means of the hydroxyapatite chromatography method of DNA hybridisation. Matrices of DELTAT(m) and DELTAT(m)H-C values were analysed with the FITCH algorithm in Felsenstein's PHYLIP (Version 3.3). Jackknifing and bootstrapping were applied to determine the stability of resulting topologies. All the phylogenetic analyses produced trees that support (1) the monophyly of the Pseudocheirus herbertensis complex, (2) the monophyly of Pseudocheirus, (3) a close relationship between Hemibelideus and Petauroides, and (4) a close relationship between Pseudochirops archeri and Pseudochirops cupreus. Rates of single-copy DNA evolution are slightly faster in Pseudocheirus, Hemibelideus, and Petauroides than in Pseudochirops. Hybridisation evidence also provides a framework for understanding the timing of the pseudocheirid radiation and suggests that the divergence between extant genera dates back to about 36 million years ago.