Early Burdigalian natricid snakes (Serpentes, Colubroidea) from Central Europe

IVANOV, Martin a Václav PACLÍK. Early Burdigalian natricid snakes (Serpentes, Colubroidea) from Central Europe. 2025.

Základní údaje

Originální název

Early Burdigalian natricid snakes (Serpentes, Colubroidea) from Central Europe

Autoři

IVANOV, Martin a Václav PACLÍK

Vydání

2025

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Další údaje

Jazyk

angličtina

Typ výsledku

Konferenční abstrakt

Obor

10505 Geology

Stát vydavatele

Polsko

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova anglicky

Early Miocene; Natricidae; comparative osteology; taxonomy; evolution

Příznaky

Mezinárodní význam, Recenzováno

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Anotace

V originále

The late Early Miocene (20.44‒15.97 Ma; Burdigalian) was a period of massive dispersal of colubriform snakes in Europe. Although natricid snakes represented the most widespread colubroid clade in the European early Burdigalian (~late MN 2 and most of MN 3; 20.4–18.2 Ma), only two genera have been reported so far from the MN 3 zone – Natrix and ‘Neonatrix’. Here we present up to date insight on the taxonomy of European early Burdigalian natricids based mainly on the postcranial anatomy of diverse snakes from two coeval (MN 3) Central European localities, Merkur-North (Ahníkov I), Czechia and recently studied Wintershof-West, Germany. We confirmed the presence of at least three natricid genera in the early Burdigalian of Central Europe (Natrix, Palaeonatrix, and a new genus more closely related to Natrix than any other Natricidae). Among known natricids, Palaeonatrix has its first occurrence in MN 3. Palaeonatrix aff. lehmani from Wintershof-West which displays a peculiar development of the hypapophysis compared to all other extinct or extant natricids, represents a distinct morphotype slightly different from the type material of Palaeonatrix lehmani from Dolnice, Czechia (MN 4b). It is possible that Palaeonatrix aff. lehmani from Wintershof-West might belong to the evolutionary older members of Palaeonatrix lehmani lineage. The genus Natrix is represented by two species, Natrix merkurensis and Natrix sansaniensis, having their first occurrence in MN 3 zone. Although isolated cranial bones (compound bone, quadrate, ectopterygoid, and maxilla) have rarely been described in Natrix merkurensis and Natrix sansaniensis in Merkur-North (Ahníkov I), important braincase elements, being of crucial importance for the genus level allocation, are absent. Therefore, the earliest indisputable representative of Natrix, identified on the basis of the fragmentary posterior portion of the parabasisphenoid, comes from the middle Burdigalian (MN 4) of Echzell, Germany, although we consider that its allocation to Natrix longivertebrata is unlikely. The simultaneous appearance of the extinct Natrix merkurensis and Natrix sansaniensis in the early Burdigalian (MN 3) of Central Europe supports the assumption of a rapid diversification of the Natrix lineage about 20–18 Ma supported by molecular studies. We consider the Eurasian small sized natricid morphotype from Wintershof-West, which closely resembles that of ‘Neonatrix’ crassa, a member of the lineage different from the North American Neonatrix and most probably belonging to a separate/new genus. The early Burdigalian dispersal of Natricidae and other diversified colubriform snakes was a fundamental event in the evolution of modern European snake fauna closely related to humid conditions and warming preceding the thermal optimum of the Miocene Climatic Optimum.