Search

Populations of the lizard Zootoca vivipara (Juaquin, 1787) (Lacertidae, Sauria) from Western and Central Europe are poorly differentiated in morphology. However, they differ from each other by several karyotype markers and their reproductive mode (oviparous and viviparous types). Here we report for the first time the results of combined investigations of Z. vivipara from Eastern Europe (the Baltic Sea basin of Western Russia). The karyotype and reproductive mode of the specimens from four previously not examined populations in Kaliningrad region have been studied. It has been shown that these lizards have viviparous mode of reproduction and their karyotypes vary on morphology of W-sex chromosomes. Females possess 2n = 35 : 32 A + Z1Z2W, with W--SV and 2n = 35 : 32 A + Z1Z2W, with W--A/ST. We have identified these populations karyologically and have first revealed that they belong to two different viviparous forms of nominative subspecies Z. v. vivipara, namely to its "western" and "Russian (eastern)" forms. These data have confirmed that the Baltic Sea basin in Eastern Europe is a zone of secondary contact of these chromosomal forms of Z. v. vivipara. The results obtained do not now allow us to speak about their sympatry, parapatry and (or) hybridization events. The results suggest that during postglasial time "western" form might colonize this region from western Europe whereas "Russian (eastern)" form might do it from Southern-Eastern Europe. It has been recommended to save the biodiversity of Z. vivipara in Kaliningrad region, namely the peripheral and very rare on vast territory of Russia "western" form and unique for western region of Russia "Russian (eastern)" form.