The dinoflagellate species Gonyaulax pacifica Kofoid is reported for the first time from northeastern Mediterranean coast of Turkey; it has not previously been reported for any Turkish coastal waters. The morphological characteristics of this species are described in detail and information about its ecological and biogeographical distribution is given. | Turk J Bot 31 (2007) 67-70 © TÜB‹TAK Research Note New Record for a Dinoflagellate Species (Gonyaulax pacifica Kofoid) from Turkish Coastal Waters (Northeastern Mediterranean Sea) Sevim POLAT* Çukurova University, Faculty of Fisheries, 01330 Balcal›, Adana - TURKEY Received: Accepted: Abstract: The dinoflagellate species Gonyaulax pacifica Kofoid is reported for the first time from northeastern Mediterranean coast of Turkey; it has not previously been reported for any Turkish coastal waters. The morphological characteristics of this species are described in detail and information about its ecological and biogeographical distribution is given. Key Words: Gonyaulax pacifica, dinoflagellate, phytoplankton, northeastern Mediterranean Türkiye K›y›sal Sular›nda (Kuzeydo¤u Akdeniz) Dinoflagellatlardan (Gonyaulax pacifica Kofoid) Yeni Bir Kay›t Özet: Dinoflagellat üyesi Gonyaulax cinsine ait Gonyaulax pacifica Kofoid, Türkiye’nin kuzeydo¤u Akdeniz k›y›sal sular›ndan ilk kez rapor edilmifltir. Bu tür ayn› zamanda tüm Türkiye k›y›sal sular› için de yeni kay›tt›r. Bu türün morfolojik özellikleri detayl› olarak aç›klanm›fl, ekolojik ve biyoco¤rafik da¤›l›mlar› ile ilgili bilgiler verilmifltir. Anahtar Sözcükler: Gonyaulax pacifica, dinoflagellat, fitoplankton, kuzeydo¤u Akdeniz Introduction Dinoflagellates are one of the major constituent of marine phytoplankton. They are unicellular, eucaryotic, flagellated organisms that posses both photosynthetic and nonphotosynthetic members (Taylor, 1987); 4060% of the living species are photosynthetic. There are about 1555 dinoflagellate species in the world oceans (Gomez, 2005). The eastern Mediterranean is described as the most oligotrophic part of the Mediterranean Sea. The high temperature prevailing in the eastern Mediterranean, especially compared to its western basin, gives this region a tropical character with regard to planktonic biota (Kimor, 1983). The oligotrophic conditions in the Mediterranean could