Holocene herpetofauna from the Zarechye locality on Vikhra (Belarus)

Abstract

Introduction: The locality is situated on the left bank of the river Vihra in the Zarechye tract near the northern outskirts of Mstislavl. Fossil remains of small vertebrates were washed from mixed-grained sands with wood remains and mollusk shells at a depth of 1.6 – 1.8 m.

Geological age and preservation of the material: The remains of small mammals belong to the following species: Sorex coecutiens, Sorex minutus, Sorex araneus, Neomys fodiens, Sicista betulina, Apodemus agrarius, Apodemus silvaticus, Apodemus flavicollis, Arvicola terrestris, Microtus oeconomus, Microtus agrestis, Microtus arvalis, Microtus subterraneus, Cllethrionomys glareolus. The ecological structure and species composition of micromammals allows us to attribute the fauna of this locality to the climatic optimum of the Middle Holocene (Atlantic). 117 bones that belonged to tailless amphibians and squamated reptiles were found in the locality.

Systematic part: A description of the most systematically important bones of amphibians and reptiles is given: Bufo bufo, Rana temporaria, Zootoca vivipara, Natrix natrix, Colubrinae indet., Vipera berus.

Discussion and conclusions. Six species from four families are present in the oryctocenosis, of which five species live in Belarus at present. Four species (Bufo bufo, Rana temporaria, Zootoca vivipara, Vipera berus) are typical inhabitants of closed biotopes. The fifth (Natrix natrix) is an intrazonal aquatic species, most of whose range is located within the forest zone. Thus, the species composition indicates the existence of a humid forest environment.

The discovery of a vertebra of the sixth species in this collection, identified as Colubrinae indet., is very interesting. Its morphology differs from the vertebrae of Coronella austriaca, as well as from the vertebrae of other snakes whose areas are close to the territory of Belarus. It can be assumed that the oryctocenosis was formed under conditions of a warmer or less contrasting climate than currently exists in the vicinity of the locality. Such a situation could have existed here during the Atlantic period of the Holocene.