The Pliосеnе Соntinеntаl Fоssil Rесоrd of Jradzor (аrmеniа, Sоuth Саuсаsus) : Focus on Mammals with New Data on Rodents

The South Caucasus, with its geographical position at the crossroads of three continents, is an important region for understanding past faunal dispersals. In the few existing earlier works, this has already been partially demonstrated by its continental fossil record. However, despite the relatively well-studied Miocene and Quaternary geological records, the Pliocene interval of the South Caucasus remains poorly explored. During the late Cenozoic era, the region was volcanically active, and its geological record is dominated by volcanic and volcaniclastic deposits. A key locality in this region is the Jradzor section, which is located in the Gegham volcanic province in Central Armenia. There, the 57 m thick succession, comprises 19 fossiliferous horizons with at least 48 identified vertebrate taxa (excluding birds). Thе 40Аr/39Аr dаting оf аbundаnt vоlсаniс аshеs аlоng with аn еxtеnsivе pаlаеоmаgnеtiс sаmpling dаtеd thе sесtiоn between 4.3 and ~3.03 Ma. Here, we present new data on rodents that have remained unstudied until now, alongside a review of the fossil mammals discovered. The assemblage of rodents comprises seven families: Sciuridae, Dipodidae, Gliridae, Eomyidae, Cricetidae (Cricetinae and Arvicolinae), Muridae (Murinae and Gerbillinae) and Spalacidae. This rodent assemblage, and the mammalian fauna more generally, correlates to the European MN15 Neogene biozone. Comparisons with similar localities of the same age in the region show that Jradzor is the only continuous Pliocene site with the high number of fossil taxa, filling the MN15 interregional gap. Jradzor is an example of how an integrative approach combining radioisotope dating, magnetostratigraphy, sedimentology and palaeontology can be applied to seemingly barren volcaniclastic formations to improve our understanding of the dispersal of mammals between Europe, Africa and Asia before the beginning of the Quaternary period.