Amphilagus plicadentis (Lagomorpha, Mammalia) from the Tagay locality (Olkhon Island, Baikal region, Eastern Siberia)

Abstract

New excavations in the Tagay locality have revealed the presence of Amphilagus plicadentis Erbajeva, 2013, which belongs to the palaeolagine Lagomorpha rather than leporids, previously referred to Procaprolagus sp. (Logachev et al., 1964). Herein, we report a comprehensive morphological description of this species and compare it with the other known species of the genus Amphilagus. The Tagay lagomorph is conspecific with the Early Miocene species Amphilagus plicadentis found at locality Unkheltseg (UNCH-A) (biozone D; Early Miocene) in the Valley of Lakes, Central Mongolia. The Tagay specimens suggest a more advanced evolutionary stage of A. plicadentis and an age around Early/Middle Miocene transition.

Palaeomagnetic data from the late Cenozoic Tagay section (Olkhon Island, Baikal region, Eastern Siberia)

“…This 13.5 m. thick section consists of Miocene slope and shallow lake deposits in the form of mottled sandy clay, loam and silt with horizons of pelitomorphic limestone and numerous inclusions of various faunal remains at different levels. In total 17 layers were recognised in the section (from top to bottom), palaeontological findings are concentrated in the layers 3, 5, 6, 7, 9, 10 and 11 (Daxner-Höck et al 2022a, 2022b, 2022c2022dErbajeva et al 2022;Mörs et al 2022;Voyta et al 2022, all this issue; Fig. 2).…”

“…Some genera appeared first in the late Oligocene (Ansomys, Lamugaulus, Amphilagus), others in the Early Miocene (Spermophilinus, Leptodontomys, Keramidomys and Democricetodon), only Gobicricetodon, hitherto only known from the Middle and Late Miocene, has its first appearance in Tagay. More precise biostratigraphic data derive from the species level of these genera (see Daxner-Höck et al 2022a, 2022b, 2022c, 2022dErbajeva et al 2022;Mörs et al 2022, all this issue). Almost all species from Tagay-1 show strong affinities with taxa from the Early Miocene (concerning primordial dental characters and/or size), and they differ considerably from younger (middle and late Miocene) species of the respective genera.…”