Genetic identification, morphology and distribution of Natrix helvetica subspecies in southern and western Switzerland (Reptilia, Squamata, Serpentes)

By

Schild, Andreas
Baur, Hannes.
Hertwig, Stefan T.
Fritz, Uwe
Ursenbacher, Sylvain

Type

Article

Date of Publication

2024

Original Publication

ZooKeys

Volume

1205

Pages

223--238

Subjects

microsatellites , mitochondrial DNA , morphometrics , nuclear DNA , taxonomy

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/zookeys.1205.123911

 

Abstract

Most of Switzerland is inhabited by the nominotypical subspecies of the barred grass snake (Natrix helvetica helvetica), which is characterized by mitochondrial DNA lineage E. Only in the northeast of the country, the common grass snake (N. natrix) occurs and hybridizes with N. h. helvetica in a narrow contact zone. However, we discovered that in southern and western Switzerland barred grass snakes representing another mtDNA lineage (lineage C) are widely distributed. Lineage C is typical for Alpine populations of the southern subspecies N. h. sicula. Our microsatellite analyses of the Swiss samples revealed differences between the two subspecies and also a substructure with two clusters in each subspecies. Furthermore, we discovered a contact and hybrid zone of N. h. helvetica and N. h. sicula along the northern shore of Lake Geneva and also confirm that interbreeding with alien common grass snakes (N. n. moreotica, mtDNA lineage 7) occurs there. This finding is of concern for nature conservation and measures should be taken to prevent further genetic pollution. Using morphometrics, we found no differences between the two subspecies of N. helvetica, while N. natrix was slightly distinct from N. helvetica.