In case you are interested in NE Atlantic species: You may order a pdf of the excellent 'British Marine Amphipoda: Gammaridea' by Roger Lincoln (1979) on the site: http://www.pisces-conservation.com/softlinc.html. However, some names have changed since 1979, for example Echinogammarus marinus is mentioned as Chaetogammarus marinus. But it is a very nice book, 568 pages and it has a key to 271 British marine and brackish-water gammaridean species.

In case you are interested in NE Atlantic species: You may order a pdf of the excellent 'British Marine Amphipoda: Gammaridea' by Roger Lincoln (1979) on the site: http://www.pisces-conservation.com/softlinc.html. However, some names have changed since 1979, for example Echinogammarus marinus is mentioned as Chaetogammarus marinus. But it is a very nice book, 568 pages and it has a key to 271 British marine and brackish-water gammaridean species.

You can check out Marine Species Identification Portal's website from the provided link where they list Echinogammarus marinus. I have a pdf copy of The Families and Genera of Marine Gammaridean Amphipods by Barnard and Karaman (1991) but the online resources may be more help to you than this key.   

http://species-identification.org/search.php?search_for=Echinogammarus&x=0&y=0

For Amphipod fauna from Mediterranean waters and perhaps genera revision look upon the papers and books by Denis BELLAN-SANTINI and Richard EL KAÏM (from the Endoume Marine Station, Oceanographic Center of Marseille, Aix-Marseille Univ.)

[email protected], ou [email protected]

Both authors were good friends of my "ami" Prof. Luis SALDANHA (Lisboa).

Bernard A. Thomassin, [email protected]

Dear Francisco,

in my opinion the frst coice for the genus Echinogammarus is the Revision of this genus by Pinkster in 1993. For E. marinus see p. 148 in the attachment