New evidence for the murine origins of the Otomyinae (Mammalia, Rodentia) and the age of Bolt's Farm (South Africa)

We describe a new species of muroid rodent from Bolt's Farm (Waypoint 160): Euryotomys bolti nov, sp. This new species is morphologically intermediate between Euryotomys pelomyoides Pocock, 1976 and the first earliest known t rue otomyine. This discovery has two main implications. First, the new spec ies brings strong palaeontological arguments in favour of a murine origin o f the Otomyinae and reinforces the molecular evidence. Second, it indicates that Waypoint 160 deposits are 4-5 Myr old, and confirms the suggestion ma de by Cooke(11) that there are sites of different ages in the Bolt's Farm a rea. It also implies that this particular site may be the oldest yet discov ered within the Krugersdorp region.