Diversity, taxonomy and phylogenetic relationships of the “ Niphargus borutzkyi ” ingroup (Crustacea: Amphipoda: Niphargidae) in Western Georgia, SW Caucasus Author Marin, Ivan A. N. Severtsov Institute of Ecology and Evolution, RAS, Leninsky prosp., 33, 119071, Moscow, Russia Author Barjadze, Shalva 0000-0001-8992-4987 Institute of Zoology, Ilia State University, Giorgi Tsereteli 3, 0162, Tbilisi, Georgia & shalva. barjadze @ yahoo. com; https: // orcid. org / 0000 - 0001 - 8992 - 4987 shalva.barjadze@yahoo.com Author Maghradze, Eter 0000-0002-4796-9439 Institute of Zoology, Ilia State University, Giorgi Tsereteli 3, 0162, Tbilisi, Georgia & eter. magradze. 1 @ iliauni. edu. ge; https: // orcid. org / 0000 - 0002 - 4796 - 9439 eter.magradze.1@iliauni.edu.ge Author Palatov, Dmitry 0000-0002-8826-9316 A. N. Severtsov Institute of Ecology and Evolution, RAS, Leninsky prosp., 33, 119071, Moscow, Russia & triops @ mail. ru; https: // orcid. org / 0000 - 0002 - 8826 - 9316 triops@mail.ru text Zootaxa 2023 2023-10-05 5352 4 477 500 http://dx.doi.org/10.11646/zootaxa.5352.4.2 journal article 10.11646/zootaxa.5352.4.2 1175-5326 8426401 4497FA6F-FB5D-475A-90A0-24BA499D3D4A Identification key to the species of the “ Niphargus borutzkyi ” ingroup from Imereti and the Racha-Lechkhumi and Kvemo-Svaneti regions, Western Georgia : 1. Distal article of uropod III in females about 3 times shorter than the previous one.................................. 2 - Distal article of uropod III in females about 5 and more times shorter than the previous one.......................... 3 2. Main (basal) part of dactyli of pereiopods VI –VII about 2 times longer wide; urosomite II with 4 stout dorsoposterior spine-like setae................................................................... Niphargus borutzkyi Birštein, 1933 - Main (basal) part of dactyli of pereiopods VI –VII not more than 1.5 times longer wide; Urosomite II with 3 stout dorsoposterior spine-like setae............................................................... Niphargus amirani Marin, 2020 3. Epimeral plate III with distinctly bluntly produced posteroventral angle; main (basal) part of dactyli of pereiopods VI –VII 4 times longer wide; urosomite II with 3 stout spine-like setae; distal segment of uropod III about 1.5 times shorter than previous one; 6–7 hooks in retinacules of pleopods................................... Niphargus rachalechkhumensis sp. nov. - Epimeral plate III with non-produced posteroventral angle, almost rectangular; main (basal) part of dactyli of pereiopods VI –VII not more than 2.5–3 times longer wide; urosomite II with 4 slender spine-like setae; distal segment of uropod III more than 2 times shorter than previous one; 7–10 hooks in retinacules of pleopods.............. Niphargus tvishiensis sp. nov.