New middle Eocene archaeocetes (Cetacea: Mammalia) from the Kuldana Formation of northern Pakistan

Two new species of fossil cetaceans (Pakicetus calcis and Pakicetus chittas) are described from a new locality in the Kuldana Formation (Lutetian, middle Eocene) of the Kala Chitta Hills in Northern Pakistan. Additional dentitions of the pakicetid Nalacetus ratimitus, the remingtonocetid Attockicetus, and additional dental material of the holotype of Ambulocetus natans are also described. Dental morphology of Nalacetus is intermediate between pakicetids and ambulocetids, as indicated by the presence of an ambulocetid-like P4, but pakicetid-like molars. Premolars of the specimen tentatively described as Attockicetus imply that some pakicetids and remingtonocetids were coeval. Furthermore, the new pakicetid dentitions described here are the most complete to date and further our understanding of pakicetid dental diversity.