Özbek M.Yurga L.Külköylüoglu O.2019-10-272019-10-2720131300-01791300-0179https://doi.org/10.3906/zoo-1209-14https://hdl.handle.net/11454/26498A new species of freshwater amphipod, Gammarus baysali sp. nov., collected from Cumayani{dotless} 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. © TÜBİTAK.en10.3906/zoo-1209-14info:eu-repo/semantics/closedAccessFreshwaterGammarusNew speciesTurkeyZonguldakArticle372163171Q3