An early Miocene skeleton ofBrachydiceratheriumLavocat, 1951 (Mammalia, Perissodactyla) from the Baikal area, Russia, and a revised phylogeny of Eurasian teleoceratines

Abstract

AbstractHippo-like rhinocerotids, or teleoceratines, were a conspicuous component of Holarctic Miocene mammalian faunas, but their phylogenetic relationships are widely under-investigated. Excavations in lower Miocene deposits of the Olkhon Island (Tagay locality, Eastern Siberia; 16–18 Ma) have opened a unique window on the poorly-known early history of the Lake Baikal ecosystems, notably in unearthing a skeleton of the teleoceratineBrachydiceratherium shanwangense(Wang, 1965). The concerned remains provide new insights into craniomandibular, dental, and postcranial morpho-anatomy of this elusive species. Comparison to most teleoceratine species described in Eurasia allows for proposing phylogenetic relationships among Teleoceratina through a formal parsimony analysis.DiaceratheriumDietrich, 1931, as a monotypic genus (earliest Miocene, Western Europe), is retrieved as the earliest teleoceratine offshoot. Other genera are both plurispecific and monophyletic, withProsantorhinusHeissig, 1974 (early Miocene, Eurasia) andTeleocerasHatcher, 1894 (Miocene, North America) forming the sister clade of the (BrachypotheriumRoger, 1904 (Miocene, Old World) plusBrachydiceratheriumLavocat, 1951) clade. The latter genus includes eight species spanning the late Oligocene–late Miocene interval in Europe and Asia. All teleoceratine genera butDiaceratheriumspan considerable geographical and stratigraphical ranges, likely related to their ultra-generalist ecological preferences.