Gammaridae
Creators: name: Copilaș-Ciocianu, Denis
name: Sidorov, Dmitry
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Amphipoda
Gammaridae

description: Key to genera (endemic Ponto-Caspian gammaroid radiation)
1. Gnathopods chelate ................................… Caspicola (monotypic: Caspicola knipovitschi (Derzhavin, 1944)
- Gnathopods subchelate .............................................. 2
2. Head with lateral projections …............................... 3
- Head without lateral projections ................................ 5
3. Strong lateral-pointing spine on pereonite 5 ......................................................................... Axelboeckia (monotypic: Axelboeckia spinosa (Sars, 1894a, 1894b))
- No spines, only blunt knobs on pereonite 5 ............... 4
4. Body with two dorso-lateral rows of knobs ................ ........................................................................... Kuzmelina (monotypic: Kuzmelina kusnezowi (Sowinsky, 1894))
- Body with a central dorsal keel on pereonal segments 6–7 and pleosome ........................................... Gmelinopsis
5. Antenna 1 accessory flagellum uniarticulate ............ 6
- Antenna 1 accessory flagellum two- or multiarticulated ......................................................................................... 10
6. Lateral head lobes form a characteristic “hood” ............................................................................ Scytaelina (monotypic: Scytaelina simplex (Stock et al., 1998))
- Lateral head lobes normal .......................................... 7
7. Bases of pereopods 5–6 lobed, uropod 3 reduced ....................................................................... Behningiella (monotypic: Behningiella brachypus (Derzhavin, 1948))
- Bases of pereopods 5–6 not lobed, uropod 3 normal ... 8
8. Body with an obvious central dorsal keel, more pronounced on the pleosome ..................................... Gmelina
- Body with a weak or absent central dorsal keel ......... 9
9. Pereopod 7 basis with a large downward pointing postero-distal lobe ..................................... Jugogammarus (monotypic: Jugogammarus kusceri (Karaman, 1931))
- Pereopod 7 basis with minute/without a downward pointing postero-distal lobe ............................... Yogmelina
10. Gnathopod 1 broader and larger than gnathopod 2 ........................................................................................ 11
- Gnathopod 1 equal or smaller than gnathopod 2 ..... 13
11. Uropod 3 reduced, exopod shorter than twice the peduncle length .......................................................... Baku (monotypic: Baku paradoxus (Derzhavin in Derzhavin & Pjatakova, 1967))
- Uropod 3 normal, exopod at least twice the peduncle length .............................................................................. 12
12. Dactyli of pereopods 3–7 prehensile ...... Iphigenella (monotypic: Iphigenella acanthopoda (Sars, 1896))
- Dactyli of pereopods 3 – 7 not prehensile ............................................................... Lanceogammarus (monotypic: Lanceogammarus andrussowi (Sars, 1896))
13. Pereopod 7 basis not lobed ................................... 14
- Pereopod 7 basis lobed ............................................ 18
14. Antenna 1 accessory flagellum bi-articulated ....................................................................... Cardiophilus
- Antenna 1 accessory flagellum tri- or more articulated ........................................................................................ 15
15. Antenna 2 peduncle greatly expanded, article 3 with a downward projection .................................. Derzhavinella
- Antenna 2 peduncle normal, article 3 without a downward projection ............................................................... 16
16. Antenna 1 peduncle article 3 longer or equal with article 1 ............................................................. Sowinskya (monotypic: Sowinskya macrocera (Derzhavin, 1948))
- Antenna 1 peduncle article 3 shorter than article 1 ... 17
17. Uropod 3 setae curled, longer than spines ................................................................ Trichogammarus (monotypic: Trichogammarus trichiatus (Martynov, 1932))
- Uropod 3 setae straight, shorter than spines ............................................................... Chaetogammarus
18. Pereopod 6 basis lobed ........................................ 19
- Pereopod 6 basis not lobed ...................................... 20
19. Pereopod 5–7 meral articles with a postero-distal lobe .............................................................................. Zernovia (monotypic: Zernovia volgensis (Derzhavin, 1948))
- Pereopod 5–7 meral articles without a postero-distal lobe ........................................................ Shablogammarus (monotypic: Shablogammarus shablensis (Cărău Ș u, 1943))
20. Antenna 1 flagellum shorter than peduncle .......... 21
- Antenna 1 flagellum equal/longer than peduncle ..... 25
21. Epimeron 3 with postero-ventral setal fan ............ 22
- Epimeron 3 without postero-ventral setal fan .......... 24
22. Uropod 3 endopod longer than half of exopod ................................................................. Uroniphargoides (monotypic: Uroniphargoides spinicaudatus (Cărău Ș u, 1943))
- Uropod 3 endopod shorter than half of exopod ........ 23
23. Ganthopod 2 propodus palm longer than posterior margin .............................................. Compactogammarus (monotypic: Compactogammarus compactus (Sars, 1895))
- Ganthopod 2 propodus palm shorter than posterior margin ................................................................ Niphargoides
24. Uropod 3 exopod 2nd article well developed, bearing lateral setae ........................................ Niphargogammarus
- Uropod 3 exopod 2nd article minute/absent, bearing no lateral setae ............................................ Paraniphargoides
25. Eyes round to ovoid, gnathopod 2 propodus large and triangular, armed with a palmar spine as long as 1/3 of dactylus .............................................................. Pandorites (monotypic: Pandorites podoceroides (Sars, 1896))
- Eyes reniform, gnathopod 2 propodus armed with a palmar spine(s) shorter than 1/3 of dactylus ....................... 26
26. Antenna 1 peduncular article 1 slender, width not exceeding 1/3 of length, pereopods 3–4 with sparse setae shorter than the width of underlying segment ................ 27
- Antenna 1 peduncular article 1 robust, width exceeding 1/3 of length, pereopods 3–4 with dense setae as long as/longer than the width of underlying segment (except O. subnudus) ....................................................................... 30
27. Body with a central dorsal a keel ......... Amathillina
- Body without a keel ................................................. 28
28. Head swollen and enlarged ....... Cephalogammarus (monotypic: Cephalogammarus macrocephalus (Sars, 1896))
- Head normal ............................................................ 29
29. Urosomites 1–2 with columnar tubercles ................................................................ Dikerogammarus
- Urosomites 1–2 without columnar tubercles ................................................................. Akerogammarus
30. Uropod 3 exopod 2nd article at least 1/5 the length of 1st article .................................................................... 31
- Uropod 3 exopod 2nd article much shorter than 1/5 the length of 1st article ......................................................... 32
31. Uropod 3 exopod outer margin armed with few simple setae ......................................................... Stenogammarus
- Uropod 3 exopod outer margin armed with many plumose setae ............................................... Wolgagammarus (monotypic: Wolgagammarus dzjubani (Mordukhai-Boltovskoi & Ljakhov, 1972))
32. Setae on posterior margin of carpal articles of pereopods 3–4 arranged in a continuous fan .... Pontogammarus
- Setae on posterior margin of carpal articles of pereopods 3–4 arranged in clusters .................................................. 33
33. Urosomites 1–2 with noticeable dorsal knobs .................................................................. Turcogammarus
- Urosomites 1–2 flat or humped ........ Obesogammarus
description: Published as part of Copilaș-Ciocianu, Denis & Sidorov, Dmitry, 2022, Taxonomic, ecological and morphological diversity of Ponto-Caspian gammaroidean amphipods: a review, pp. 285-315 in Organisms Diversity & Evolution (New York, N. Y.) (New York, N. Y.) 22 (2) on pages 307-308, DOI: 10.1007/s13127-021-00536-6, http://zenodo.org/record/13366423