Palaeobatrachid frog from the late Miocene of Northern Caucasus, Russia

[摘要] Disarticulated remains of Palaeobatrachus sp. (Palaeobatrachidae) from the late Miocene (early Turolian, MN 11; about 8-7.5 m.y.) of Volchaya Balka and Gaverdovsky localities (Northern Caucasus, Russia) are described. Palaeobatrachus from Volchaya Balka and Gaverdovsky differs from other species of the genus by having four premaxillary teeth. It shows an intermediate dentition between pre-Pliocene palaeobatrachids with five or more premaxillary teeth and Pleistocene congeners with two or three premaxillary teeth. The variations in the frontoparietals and synsacra may indicate that two species of Palaeobatrachus co-existed in Volchaya Balka and Gaverdovsky. The wide contribution of the transverse processes of V7+8+9 in the sacral wings of Palaeobatrachus from Volchaya Balka and Gaverdovsky shows that palaeobatrachids probably reached an extreme degree of aquatic adaptation as early as the late Miocene or even earlier. The Caucasian Palaeobatrachus partly fills the late Miocene gap (MN 10-13) in palaeobatrachid distribution and extends the Miocene range of this family to easternmost Europe (European Russia).

[学科分类] 地质学

[关键词] Elena V. Syromyatnikova;Anura;Palaeobatrachidae;Palaeobatrachus;late Miocene;Caucasus;Russia