Molecular phylogeny of the tribe Bovini (Bovidae, Bovinae) and the taxonomic status of the Kouprey, Bos sauveli Urbain 1937.

The kouprey is a very rare bovid species of the Indochinese peninsula, and no living specimen has been described for a long time, suggesting that it is possibly extinct. Its systematic position within the tribe Bovini remains confused since the analyses of morphological characters have led to several conflicting hypotheses. Some authors have also suggested that it could be a hybrid species produced by the crossing of the banteng with gaur, zebu, or water buffalo. Here we performed a molecular phylogeny of the tribe Bovini to determine the taxonomic status of the kouprey. DNA was extracted from the holotype specimen preserved in the MNHN collections. Phylogenetic analyses were carried out on a matrix including all the taxonomic diversity described in the tribe Bovini, and 2065 nucleotide characters, representing three different markers, i.e., the promotor of the lactoferrin and two mitochondrial genes (cytochrome b and subunit II of the cytochrome c oxidase). The results show that the kouprey belongs to the subtribe Bovina, and that three different clades can be evidenced into this group: the first includes the domestic ox, zebu, and European bison; the second incorporates the yak and American bison; and the third contains the kouprey, banteng and gaur. All hypotheses involving hybridization for the origin of the kouprey can be rejected, confirming that it is a real wild species. Molecular datings and biogeographic inferences suggest that the kouprey diverged from banteng and gaur during the Plio-Pleistocene of Asia. In addition, several molecular signatures were detected in the cytochrome b gene, permitting a molecular identification of the kouprey. We propose a conservation project based on a molecular taxonomy approach for tracking the kouprey in Indochina in order to determine whether some populations still survive in the wild.