The first detection of a putative hybrid between Miller-s and Eurasian water shrews (Neomys milleri and N. fodiens)

We report the discovery of a water shrew specimen displaying intermediate morphological characteristics between Neomys milleri and N. fodiens, found in the Ulyanovsk region (53.8359°N, 48.4986° E).This locality is considerably distant (360-420 km) from the known range of N. milleri.We describe the capture location and external characteristics of the animal and present an analysis of its mitochondrial cytb gene and three nuclear introns (TRAIP, CSF2 and GDAP1).Although the specimen's mtDNA was initially identified as N. milleri, analysis of the nuclear introns revealed mixed inheritance: two were specific to N. milleri and one to N. fodiens.This combination of characteristics suggests a hybrid origin resulting from recurrent crossbreeding.