Özbek, MuratYurga, LeventKülköylüoğlu, Okan2021-06-232021-06-2320131300-01791303-6114https://dergipark.org.tr/tr/download/article-file/134425https://hdl.handle.net/20.500.12491/7703A new species of freshwater amphipod, Gammarus baysali sp. nov., collected from Cumayani Cave (Zonguldak Province, Turkey) is described and illustrated. The new species belongs to the Gammarus pulex-group. The most discriminant characters of this species are the minute eyes, densely setose fifth peduncle and flagellar segments of antenna 2, elongated pereopods, and setose anterior margins of pereopod 5 to 7. Additionally, the palp of right maxilla 1 has 4 setae along its outer margin. A detailed morphological description and illustrations of the new species are provided, and differences from related species are discussed.eninfo:eu-repo/semantics/openAccessGammarusNew SpeciesFreshwaterZonguldakTurkeyArticle372163171Q3WOS:000321228800005Q4