Circulus (Mollusca-Gastropoda) species of the Turkish coasts with a note on the presence of Circulus octoliratus (Carpenter, 1856)

The present study is dealing with three Circulus species recorded along the Turkish coasts (İskenderun Bay, Levantine coast of Türkiye). Of the identified species, Circulus novemcarinatus and Circulus octoliratus are non-indigenous species originated outside the Mediterranean Sea, whereas Circulus striatus is a native one distributed in the eastern Atlantic Ocean and Mediterranean Sea. While Circulus novemcarinatus was recorded at depths between 9 and 60 m, Circulus octoliratus and Circulus striatus were encountered at shallow depths (5-11.7 m, respectively). Within the present study some morphological and distributional characteristics of the investigated species are described.