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

Abstract

Hippo-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 teleoceratine Brachydiceratherium 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. Diaceratherium Dietrich, 1931, as a monotypic genus (earliest Miocene, Western Europe), is retrieved as the earliest teleoceratine offshoot. Other genera are both plurispecific and monophyletic, with Prosantorhinus Heissig, 1974 (early Miocene, Eurasia) and Teleoceras Hatcher, 1894 (Miocene, North America) forming the sister clade of the (Brachypotherium Roger, 1904 (Miocene, Old World) plus Brachydiceratherium Lavocat, 1951) clade. The latter genus includes eight species spanning the late Oligocene-late Miocene interval in Europe and Asia. All teleoceratine genera but Diaceratherium span considerable geographical and stratigraphical ranges, likely related to their ultra-generalist ecological preferences.

Evolutionary paleoecology of European rhinocerotids across the Oligocene-Miocene transition

“…Pleuroceros pleuroceros had similar body mass estimates (700 kg) and mean mesowear ruler (2) at Gannat, Paulhiac (only mass), and Wischberg (Figure 5). Hypoplasia prevalence was low or null hypoplasia except at Paulhiac (25 %), but the sample size for this (Jame et al, 2019;Tissier et al, 2020Tissier et al, , 2021aSizov et al, 2023).…”

“…Phylogenetic relationships based on the literature (Jame et al, 2019; Tissier et al, 2020, 2021a; Sizov et al, 2023). …”

“…Figure 5: Hypoplasia prevalence (full line) and body mass (dashed line) by species and localityPhylogenetic relationships based on the literature(Jame et al, 2019;Tissier et al, 2020Tissier et al, , 2021aSizov et al, 2023).…”

Reconstructing the phylogeny of the hornless rhinoceros Aceratheriinae

“…This genus has long been considered an early ancestor of some advanced teleoceratini genera. Sizov et al (2022) tried to classify all species of Diaceratherium except the type species to Brachydiceratherium, indicating a complicated relationship of this genus, and put D. tomerdingense in the basal position of Teleoceratini. Together with the discussion of the relationship between Diaceratherium and Prosantorhinus by Heissig (2017), the taxonomic and phylogenetic relationships are debatable and complex.…”

Squirrels (Rodentia, Sciuridae) of the Early Miocene Tagay fauna in Eastern Siberia

“…The vertebrate fauna of Tagay has been mentioned in numerous recent publications devoted to herpetofauna (Rage and Danilov, 2008;Syromyatnikova, 2016;and others), birds (Zelenkov, 2016;Volkova and Zelenkov, 2018;Volkova, 2020;and others) and mammals (Klementiev and Sizov, 2015;Tesakov and Lopatin, 2015;Sotnikova et al, 2021;Daxner-Höck et al, 2022a and references herein;Sizov, Klementiev, and Pierre-Olivier, 2023).…”