Evolutionary history of tree squirrels
A recent paper published by Pečnerová & Martínková in Zoologica Scripta (see Publications page) using phylogenetic reconstruction shows that tree squirrels evolved in the Northern Hemisphere with the first group to diverge from a common ancestor being Tamiasciurus followed by Sciurus in the Palaearctic and Reithrosciurus in Indo-Malayasia. Thereafter overland colonisation resulted in the present-day distribution of tree squirrels.