The first and so far the only published record of the land snail Discus rotundatus in Turkey is from Anadolu Hisari, a 14th century fort on the Asian side of the Bosphorus in Istanbul, where I found it in August 20021. It is certainly an introduced species at least in the Istanbul area.
The native distribution range of D. rotundatus covers western and central Europe. It has also been introduced to other countries, including the U.S.
The shell of D. rotundatus is characterized by a wide umbilicus, prominent ribs and reddish-brown marks. The largest shell I found was 5.4 mm in diameter. (The scale in the picture above is in millimeters.)
The land snail family Discidae, which includes the genus Discus, has native representatives both in Europe and in North America. I will return to the biogeography of the Discidae in a future post.
Archive of the Land Snails of Turkey series.
1. Örstan, A. 2003. The first record of Discus rotundatus from Turkey. Triton, No. 7, p. 27. pdf