First ascertained African “Condylarth” mammals (primitive ungulates: cf. Bulbulodentata and cf. Phenacodonta) from the earliest Ypresian of the Ouled Abdoun Basin, Morocco

Abstract

ABSTRACT We report here the discovery of the first well identified “condylarths” from Africa, from the phosphatic beds of Ouled Abdoun Basin, Morocco, of probable early Ypresian age, which have also yielded the oldest known proboscidean. Abdounodus hamdii n. gen., n. sp. and Ocepeia daouiensis, gen. et sp. nov., show closest relationships with Mioclaenidae and Phenacodonta respectively. Both taxa also have resemblances with South American primitive ungulates, especially Abdounodus which resembles kollpaniine mioclaenids in several derived features, mostly related to a similar crushing specialization. However divergent specializations in Abdounodus and kollpaniines strongly suggest their parallelisms, in accordance with their age disparity. Some features of Abdounodus appear to be even original with respect to known mioclaenids. Though Ocepeia shares peculiar derived features with phenacodontids, it is strikingly specialized in its secondarily simplified p4, indicating sister-taxa relationships within Taxeopoda (Phenacodonta, Pantomesaxonia). Moreover, Ocepeia shares a remarkable derived feature with more advanced pantomesaxonian ungulates (Perissodactyla, Hyracoidea, Tethytheria and extinct relatives): the development of an entolophid. This raises the alternative question of their sister-taxa relationships within Taxeopoda and indeed the question of an African origin of Pantomesaxonia, which is congruent with the Paenungulata hypothesis. Though still poorly documented, these new Ouled Abdoun taxa show that early Paleogene African mammal faunas might provide key-data for the problem of the origin and basal phylogeny of main pantomesaxonian ungulate lineages. These fossils show again the importance of the African scene in the early evolution of (modern) eutherians and the poor state of our knowledge there.