families

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 : 307

Key to families (parentheses indicate non-Gammaroid genera that contain more than one species; their species are keyed in the “Key to species” below).

1. Eyes absent ............................................ Niphargidae

- Eyes present ...........................................................… 2

2. Body dorso-ventrally compressed, coxal plates rudimentary, antenna 2 greatly developed … Corophiidae ( Chelicorophium )

- Body laterally compressed, coxal plates well developed, antenna 2 normally developed ......................................… 3

3. Head rostrum long and narrow, uropod 3 rami foliaceous of equal length ....................… Gammaracanthidae

- Head rostrum absent or rudimentary, uropod 3 rami slender, subequal .............................................................. 4

4. Telson uncleft .......................... Uristidae ( Onisimus )

- Telson cleft ................................................................ 5

5. Pereopod 6 much longer than pereopods 5 and 7 ................................................................... Pontoporeiidae

- Pereopod 6 as long as or slightly longer than pereopods 5 and 7 .............................................................................. 6

6. Gnathopods chelate ............................... Caspicolidae

- Gnathopods subchelate .............................................. 7

7. Pereopods 5–7 prehensile ................... Iphigenellidae

- Pereopods 5–7 not prehensile .................................... 8

8. Maxilliped and mandibular palp reduced and/or meral articles of pereopod 5–7 with postero-distal lobe ................................................................... Behningiellidae

- Maxilliped and mandibular palp normal, meral articles of pereopod 5–7 without postero-distal lobe .................... 9

9. Antenna 1 peduncle article 1 slender, as long as or shorter than articles 2 and 3 combined ......... Gammaridae

- Antenna 1 peduncle article 1 swollen, longer than articles 2 and 3 combined ......................... Pontogammaridae