First partial cranium of Togocetus from Kpogamé (Togo) and the protocetid diversity in the Togolese phosphate basin

International audienceEarliest cetaceans (whales) originated from the early Eocene of Indo-Pakistan, but the group dispersedthrough most of the oceans of the planet by the late middle to late Eocene. This late Eocene globaldistribution indicates that important dispersal events took place during the middle Eocene (Lutetian), aglobally undersampled time interval that is well documented in the Togolese phosphate series. We reporthere the first discovery of a partial cetacean cranium from middle Eocene deposits of Togo (West Africa).A 3D model of the cranium and teeth was reconstructed in order to reveal hidden anatomical features.The dental and cranial characteristics of the Togolese specimen recall those of protocetid taxa describedin Africa, Asia, and North America, but also display significant differences. In particular, we show thatthe new specimen shares a number of morphological features with the Togolese taxon Togocetus. Such ahypothesis is further supported by a cladistic analysis including 45 taxa and 167 morphological characters,which recovers the new specimen close to Togocetus as the first offshoot of protocetids. Phylogeneticanalysis including all the protocetids remains of Kpogamé confirms the singular diversity of the Togolesephosphate basin, and enables to examine potential connections with faunas from contemporaneouslocalities in Africa