Accessory scutes and asymmetries in European pond turtle, Emys orbicularis (Linnaeus, 1758) and Balkan terrapin, Mauremys rivulata (Valenciennes, 1833) from Vlora Bay, western Albania

Abstract

This study aims to provide the first information about scute anomalies occurring in the population of Emys orbicularis and Mauremys rivulata in the understudied area of Vlora Bay, Albania. Two main different habitats, freshwater channels and ponds were monitored from March 2013 to October 2015. A total of 143 individuals of E. orbicularis and 46 individuals of M. rivulata were captured and checked for the presence of scute anomalies. We found that 3.5% of the captured individuals of E. orbicularis and 13.0% of M. rivulata had conspicuous carapacial scute anomalies. The most common anomaly in both populations of E. orbicularis and M. rivulata was the accessory scutes (between vertebrals, between one costal and one vertebral, etc.) present in 36.3% of individuals. It was observed that 80% of anomalous individuals of E. orbicularis had more than one scute anomaly, while all anomalous individuals of M. rivuata had only one anomaly. Different hypotheses are discussed to explain this findings.