New Sandhoppers (Crustacea: Amphipoda) from the Gulf Coast of the United States
Bousfield, E.L. 1991. New Sandhoppers (Crustacea: Amphipoda) from the Gulf Coast of the United States. Gulf Research Reports 8(3): 271-283. https://aquila.usm.edu/gcr/vol8/iss3/7/
This open-access article includes a useful "Key to North American Genera of Sand-Burrowing Taltridae" - the key is somewhat technical (you have to know the names of the body parts).
For talitrid amphipod morphology, the following paper (also open-acces) gives a great introduction to the morphology, even though it is not focused on the North American fauna:
Fenwick, G. and R. Webber. 2008. Identification of New Zealand's terrestrial amphipods (Crustacea: Amphipoda: Talitridae). Tuhinga 19:29-56.