To help you in the identifiaction of Amphipods in general, I recommand you the 2 books of my friends : Michel LEDOYER
LEDOYER M., 1982 et 1986. Crustacés Amphipodes Gammariens. Familles des Acanthonotozomatidae à Gammaridae. Faune de Madagascar, CNRS Paris, 59 (1) : 1-598.
LEDOYER M., 1982 et 1986. Crustacés Amphipodes Gammariens. II. Famille des Haustoriidae à Vitjiazanidae, Faune de Madagascar, CNRS Paris, 59 (2) : 599-1101.
Amphipods taxonomists are today a very rare peoples, even in National Museums.
the morphological characters of new specimens are completely different from previous ones. but it is not enough for identifying. I can guess it belongs to Aoridae but I am not sure