The rediscovery of Zonites algirus in İstanbul, Turkey (Gastropoda: Pulmonata: Zonitidae)

by Aydın Örstan

A summary of Örstan A. 2003. The rediscovery of Zonites algirus in İstanbul, Turkey (Gastropoda: Pulmonata: Zonitidae). Zoology in the Middle East, 29:75-78.

On 15 August 2002 I visited Sedef Island off Istanbul in the Sea of Marmara with my friend Teri Varnalı. We were in search of land snails (and a good lunch at the nearby restaurant). Among the many shells we collected were a number of Zonites shells. At first, I was puzzled about the exact identities of these shells, but after searching thru the literature, I realized that they were Zonites algirus (Linnaeus, 1758). What was really interesting was that the species had last been recorded from Istanbul in 1863 by Mousson.

Shells of Z. algirus from Sedef Island. The leftmost shell is a juvenile and the other two are adults. The scale is in millimeters.

We found all of the shells in soil along large boulders shaded by some small trees. To my non-geologist eyes the rocks at this station did not appear to be limestone. But they effervesced when I put drops of dilute HCl on them, which indicated that they contained CaCO₃. Quite a while after I submitted this manuscript for publication, I learned from a paper on the geology of the Istanbul area that Sedef Island indeed has limestones (Önalan, 1990). I also learned that there are limestones outcrops on the mainland around Istanbul. During my future trips to Turkey I plan to search for Z. algirus at these sites to determine if the distribution of this species is limited to areas with calcareous rocks.

On Sedef Island I was lucky that Teri found one live Z. algirus. Not only did this specimen demonstrate that the species still lived on the island (I sure hope the one we took wasn't the last one!), but it also helped confirm the identification.

A false-color scan of the distal genitalia of Z. algirus from Sedef Island. I used this color combination to increase contrast, but it also created a 3-dimensional effect. The scale is in millimeters.

References

Mousson, A. (1863): Coquilles terrestres et fluviatiles recueillis dans l’Orient par M. le Dr. Alex Schäfli, VI. Constantinople. - Vierteljahrsschrift Naturforschenden Gesellschaft, 8:275-291.

Önalan, M. 1990. Istanbul Devoniyen istifindeki yumrulu kireçtaşlarının oluşumu. Maden Tetkik Arama Dergisi, No. 111:37-47.

--------------------------------------------------------------------------------------------------------------

© Copyright Aydin Örstan 2003

RETURN TO AYDIN'S LIBRARY