Proceedings of the Biological Society of Washington
Photis trapherus differs from its Californian counterpart, P. elephantis, in characters of male pereopod 6: the smallness of the posteroventral tooth on article 2, the longer article 4 with separated posterior keel and no significant posteroventrallobe, the relatively thinner article 2; the lack of distal expansion on article 4 of pereopod 7; the distinct concavity and defining tooth on the palms of gnathopods 1-2.
James Darwin Thomas and J. L. Barnard. 1991. Photis trapherus, a New Elephantine Species from the Caribbean Sea (Crustacea: Amphipoda) .Proceedings of the Biological Society of Washington , (1) : 96 -100. https://nsuworks.nova.edu/occ_facarticles/591.