Crustacean “cave fishes” from the Arabika karst massif (Abkhazia, Western Caucasus): new species of stygobiotic crustacean genera Xiphocaridinella and Niphargus from the Gegskaya Cave and adjacent area

Cave fishes are very diverse, being an important component of almost all tropical subterranean environments (e.g. Jeffery, 2001; Romero, 2001; Romero, Paulson, 2001; Culver, Pipan, 2009; Borowsky, 2018). Troglocobitis starostini (Parin, 1983) (Nemacheilidae), the only true cave-dwelling fish species presently known within the former USSR, including Europe and Central Asia, was described from the Köýtendag ridge (37°55′N 66°23′E), Chardzhou province, Turkmenistan [Parin, 1983]. The only known European stygobiotic fish is presented by the underground population of the loach genus Barbatula Linck, 1790 (Nemacheilidae), recently discovered in the Donau-Aach underground karst water system in the southern Germany [BehrmannGodel et al., 2017] (provisionally named European cave loach). The population is morphologically and genetically differentiated from the common loach Barbatula barbatula (Linnaeus, 1758), living in the adjaABSTRACT. Stygobiotic animals washed from various groundwater sources from the Arabika karst massif (Abkhazia, Western Caucasus) were studied. As a result, new species of stygobiotic crustacean genera Xiphocaridinella and Niphargus were described based on DNA (COI mtDNA gene marker) and morphological studies in the Gegskaya (Gega) Cave. These crustaceans are probably the legendary cave-dwelling “fishes” which were previously reported from the Arabika karst massif. At the same time, during the study, no real cave fish or any evidence of their presence was found. Genetic delimitation thresholds for Caucasian Niphargus species are also discussed in the paper. How to cite this article: Marin I.N. 2019. Crustacean “cave fishes” from the Arabika karst massif (Abkhazia, Western Caucasus): new species of stygobiotic crustacean genera Xiphocaridinella and Niphargus from the Gegskaya Cave and adjacent area // Arthropoda Selecta. Vol.28. No.2. P.225–245. doi: 10.15298/arthsel. 28.2.05