Phylogenetic relationships in the Ranidae. Independent origin of direct development in the genera Philautus and Taylorana

Phylogenetic relationships within a group of Ranidae were studied, particul arly between the genera Philautus and Taylorana, to determine whether their original reproductive mode (direct development) appeared independently. To study these relationships, we used the DNA sequences of the 5' end of the gene coding for mitochondrial ribosome small subunit in 28 species. Parsimo ny analysis resulted in two equiparsimonious trees, 867 steps long (CI = 0. 382; RI = 0.429). Data saturation was studied and we applied weighting (wei ght of 5 for transversions and 1 for transitions) to enhance the phylogenet ic information. The tree we obtained (2 212 steps long, CI = 0.408; RI = 0. 482) is best supported and allows us to determine clearly that direct devel opment has appeared independently in Philautus and Taylorana. in addition, it is confirmed that the genus Rana sensu late is heterogeneous. The genera Occidozyga and Phrynoglossus form a clade basal to all the group but this position is not supported. The inclusion of the Rhacophorinae in the Ranida e is confirmed. Finally, this study confirms that the relationships within the group Tomopterna sensu Boulenger, 1918 should be re-evaluated. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.