Dikerogammarus, Stebbing, 1899

Copilaș-Ciocianu, Denis & Sidorov, Dmitry, 2022, Taxonomic, ecological and morphological diversity of Ponto-Caspian gammaroidean amphipods: a review, Organisms Diversity & Evolution (New York, N. Y.) 22 (2), pp. 285-315 : 309

Key to species of Dikerogammarus

1. Pleosome segments keeled ........................ D. caspius

- Pleosome segments flat .............................................. 2

2. Urosomal tubercles low ............................ D. fluviatilis *

- Urosomal tubercles columnar, well developed .......... 3

3. Antenna 1 accessory flagellum bi-articulated ... D. gruberi

- Antenna 1 accessory flagellum 4 or more articles ...... 4

4. Propodi of gnathopods 1 and 2 with mid-palmar spine .................................................................. D. aralychensis *

- Propodi of gnathopods 1 and 2 without mid-palmar spine ................................................................................. 5

5. Medial surface of pereopod 7 basis with setae ......... 6

- Medial surface of pereopod 7 basis without setae ..... 7

6. Antenna 2 peduncular segments with numerous clusters of setae longer than the underlying segment ... D. bispinosus

- Antenna 2 peduncular segments with few clusters of setae shorter than the underlying segment ... D. istanbulensis

7. Propodi of gnathopods 1 and 2 with setae as long as propodus width .................................................. D. villosus

- Propodi of gnathopods 1 and 2 with setae much shorter than propodus width ......................................................... 8

8. Uropod 3 exopod with spines on inner and outer margins .......................................................... D. haemobaphes

- Uropod 3 exopod without spines .................. D. oskari .