Spatiotemporal Diversification of the True Frogs (GenusRana): A Historical Framework for a Widely Studied Group of Model Organisms

Abstract

True frogs of the genus Rana are widely used as model organisms in studies of development, genetics, physiology, ecology, behavior, and evolution. Comparative studies among the more than 100 species of Rana rely on an understanding of the evolutionary history and patterns of diversification of the group. We estimate a well-resolved, time-calibrated phylogeny from sequences of six nuclear and three mitochondrial loci sampled from most species of Rana, and use that phylogeny to clarify the group's diversification and global biogeography. Our analyses consistently support an "Out of Asia" pattern with two independent dispersals of Rana from East Asia to North America via Beringian land bridges. The more species-rich lineage of New World Rana appears to have experienced a rapid radiation following its colonization of the New World, especially with its expansion into montane and tropical areas of Mexico, Central America, and South America. In contrast, Old World Rana exhibit different trajectories of diversification; diversification in the Old World began very slowly and later underwent a distinct increase in speciation rate around 29-18 Ma. Net diversification is associated with environmental changes and especially intensive tectonic movements along the Asian margin from the Oligocene to early Miocene. Our phylogeny further suggests that previous classifications were misled by morphological homoplasy and plesiomorphic color patterns, as well as a reliance primarily on mitochondrial genes. We provide a phylogenetic taxonomy based on analyses of multiple nuclear and mitochondrial gene loci. [Amphibians; biogeography; diversification rate; Holarctic; transcontinental dispersal.

A new species of Rana from the Dabie Mountains in eastern China (Anura, Ranidae)

“…2). The major clades were similar to previous studies (Yuan et al 2016). The individuals of Rana sp.…”

“…In China, the genus Rana contained 17 species (Fei et al 2012) that were divided into three groups ( R. longicrus group, R. chensinensis group, and R. amurensis group) based on morphology and distribution (Fei et al 2009). Molecular phylogenies, however, indicate presence of R. longicrus , R. amurensis , R. chensinensis , R. sauteri , R. johnsi , R. shuchinae , and R. weiningensis groups within the Chinese Rana sensu lato (Che et al 2007, Yuan et al 2016). And 24 species are contains in Chinese Rana genus (AmphibiaChina 2017, Yuan et al 2016, Zhao et al 2017).…”

“…Molecular phylogenies, however, indicate presence of R. longicrus , R. amurensis , R. chensinensis , R. sauteri , R. johnsi , R. shuchinae , and R. weiningensis groups within the Chinese Rana sensu lato (Che et al 2007, Yuan et al 2016). And 24 species are contains in Chinese Rana genus (AmphibiaChina 2017, Yuan et al 2016, Zhao et al 2017). The species of the R. longicrus group are widely distributed in southern and eastern China, and the recent surge in new species descriptions suggests that these still insufficiently explored regions may contain many undescribed cryptic species (Lu and Li 2001, Lu et al 2007, Shen et al 2007, Li et al 2008, Yan et al 2011).…”

“…The true frogs of the genus Rana Linnaeus are broadly distributed across Eurasia and the Americas (Amphibia Web 2017, Frost 2016, Yuan et al 2016). Because of their body coloration and habitat preferences, the species of this genus are colloquially known as brown frogs or wood frogs (Boulenger 1920, Yan et al 2011).…”

“…Because of their body coloration and habitat preferences, the species of this genus are colloquially known as brown frogs or wood frogs (Boulenger 1920, Yan et al 2011). To date, more than 100 species are attributed to this genus, with their distribution ranges across Asia (32 species), Europe and the Near East (12 species), and the Americas (57 species) with several lineages still being not formally described (Yuan et al 2016, Amphibia Web 2017). In China, the genus Rana contained 17 species (Fei et al 2012) that were divided into three groups ( R. longicrus group, R. chensinensis group, and R. amurensis group) based on morphology and distribution (Fei et al 2009).…”