The phylogenetic position of the rodent genus typhlomys and the geographic origin of muroidea

In this report, we provide the 1st phylogenetic assessment of the evolutionary relationships of Platacanthomyidae. This enigmatic family of rodents comprises 2 genera, Platacanthomys and Typhlomys, that are distributed disjunctly in western India and southern Asia, respectively. We analyze sequence data from the nuclear genes encoding the interphotoreceptor retinoid-binding protein (IRBP) and the growth-hormone receptor (GHR) to address the relationships of Typhlomys cinereus to other rodents, with a particular focus on testing whether its evolutionary affinities lie with glirids or muroids. Our results provide compelling evidence that Typhlomys is a muroid and that it represents the earliest split within this clade. We use the resulting phylogeny to explore the origin and evolutionary history of muroid rodents. We conclude that both Myodonta and Muroidea originated in Eurasia and that the 3 earliest divergences within Muroidea were restricted to the Eurasian supercontinent. Moreover, our analyses support the view that global muroid diversity resulted from independent radiations in separate continental regions.