Niphargus borutzkyi, Birstein, 1933

Marin, Ivan, Barjadze, Shalva, Maghradze, Eter & Palatov, Dmitry, 2023, Diversity, taxonomy and phylogenetic relationships of the “ Niphargus borutzkyi ” ingroup (Crustacea: Amphipoda: Niphargidae) in Western Georgia, SW Caucasus, Zootaxa 5352 (4), pp. 477-500 : 497

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.