Supraspecies Relationships in the Subfamily Arvicolinae (Rodentia, Cricetidae): An Unexpected Result of Nuclear Gene Analysis

Phylogenetic analysis of the supraspecies relationships was carried out using partial sequences of two nuclear genes in the subfamily Arvicolinae, which is one of the youngest and species-rich groups of myomorph rodents. The analysis with the new data resolved the majority of polytomy nodes in the phylogenetic trees reported for Arvicolinae, suggesting a gradual, rather than a saltatory, mode for their evolution. Mole voles Ellobiusini, steppe voles Lagurini, and gray voles Arvicolini were fount to be a monophyletic group that corresponds to the latest third wave of radiation within the subfamily. Red-back voles Myodini (=Clethrionomini) are a sister clade to this group and correspond to the second radiation wave. The order of divergence remained unresolved for the earliest radiation wave (Ondatrini, Prometheomyini, Dicrostonychini, and Lemmini). The close relationships observed for mole, gray, and steppe voles are unexpected and contradict the conventional views that Ellobiusini are an ancient group and are separate from all other voles on evidence of the extreme simplicity of their rooted molars and the peculiar structure of their skull and postcranial skeleton. It was assumed that many of these morphological characters indicate adaptation to subterranean life and provide no phylogenetic signal.