Revision of Iphimediidae and similar families (Amphipoda : Gammaridea)

— The amphipod families Acanthonotozomatidae, Amathillopsidae, Astryidae, Epimeriidae (=Paramphithoidae), Iphimediidae, Ochlesidae and Stilipedidae are rediagnosed and three new families, Acanthonotozomellidae, Dikwidae, and Odiidae are described. New keys distinguish these families; other similar families, Lafystiidae and Laphystiopsidae are diagnosed and included in the keys. In the process of rediagnosing the Ochlesidae Stebbing, 1910 (see Coleman & Barnard 1991a), as a family distinct from Iphimediidae, we determined that other alterations to the taxonomy of the Iphimediidae and Epimeriidae were necessary. Our contribution here offers a different division than used in the past based on characters not previously used or inconsistently used to define these groups. For example, we found relatively good consistency of characters on incisors, rakers, gnathopods and coxae in proposing this new division of the