Ventral scales numbers, anomalies and body mass index in three sympatric snake species within Norway

Ventral scales numbers, anomalies and body mass index in three sympatric snake species within Norway PÅL SØRENSEN1, BEATE STRØM JOHANSEN2*, & SVEIN OLAV NYBERG3 1Bodøgata 2, 0565 Oslo, Norway 2*Natural History Museum and Botanical Garden, University of Agder, Gimleveien 27, Gimle Gård, 4630 Kristiansand, Norway 3Dept. of Technology, University of Agder, Postboks 509, 4898 Grimstad, Norway *Corresponding author e-mail: beate.johansen@uia.no Island studies indicate that reductions in genetic diversity may cause altered number of ventral and subcaudal scales in snakes. Today, Norway represents the northwestern distribution border of Natrix natrix, Coronella austriaca and Vipera berus on continental Europe. The post-glacial dispersal of these three snake species into Fennoscandia may have resulted from a few founder individuals able to survive in the northern climate. Extant snakes are larger in size in Norway compared to central and southern Europe. This increase in body size may be caused by a larger number of vertebrae/ventral scales. Our aim is to evaluate whether regional differences in number of ventral and subcaudal scales exists within Norway for the three snake species and make comparisons with other European studies. We additionally test for other regional morphological differences, as the occurrence and number of anomalies in supralabial, ventral and subcaudal scales. We measured, weighted and photographed snake specimens from museum collections and live snakes. All the scales and anomalies were counted by the first author, and an anomaly-code system was developed based on earlier systems. The data is currently under statistical analysis, and new results will be presented at the congress.