Enamel microstructure defines a major Paleogene hippopotamoid clade: the Merycopotamini (Cetartiodactyla, Hippopotamoidea)
Résumé
We present new material of the selenodont anthracothere Hemimeryx blanfordi from the Oligocene depositsof the Bugti Hills (Balochistan, Pakistan), collected between 1999 and 2002. This is the first undisputedOligocene occurrence of the species, previously known from the early Miocene of Pakistan. Investigationof the molar enamel microstructure reveals a surprising mono-zonal Schmelzmuster, already detected insome middle to Late miocene selenedont anthracotheres. We include this observation combined witha morphological revision of H. blanfordi and a cladistic assessment of the dental evidence, to propose anew phylogenetic hypothesis regarding Hemimeryx and its close relatives. We confirm the clade includingadvanced bothriodontines, which we erect to a tribe rank and name Merycopotamini. The South Asianorigin of Merycopotamini is consistent with hypothesized subsequent dispersal events of Merycopotaminifrom Asia to Africa.