Species boundaries in the Rana arfaki group (Anura: Ranidae) and phylogenetic relationships to other New Guinean Rana

Abstract

Allozyme electrophoresis is used to explore molecular genetic relationships within the Rana arfaki group and between this group and selected lineages of New Guinean Rana. Rana jimiensis is confirmed as a species distinct from R. arfakiand its range in Papua New Guinea is extended to the Southern Highlands Province and the north-coastal ranges in Sandaun Province. Rana arfaki and R. jimiensis show a high level of genetic differentiation maintained across a wide geographic area and show consistent morphological differences in head shape, tympanum size, degree of digital disc dilation and extent of sexual dimorphism. The two species occur syntopically on the Papuan Plateau, Southern Highlands Province, and are regionally sympatric in Sandaun Province. The observed level of genetic differentiation is equivalent to that reported previously between regionally sympatric members of the Rana papua group. Populations of R. jimiensisfrom north and south of the central cordillera show no obvious morphological and only minor genetic differentiation. In contrast, R. arfaki shows considerable geographic variation in both morphology and allozymes and may include two or more regionally distinctive forms.