Diagnosis: (modified after Bird & Holdich 1988) cephalothorax shorter than pereonites 1 and 2 together. Pleonites and pleotelson apparently fused in female, with normal segmentation in preparatory and adult males. Antennule composed of four articles. Antenna composed of six articles, articles 2 and 3 each with one short superior seta. Pars molaris reduced. Lacinia mobilis of left mandible small and spiniform or reduced. Maxillule endite with eight or nine terminal spines. Maxilliped basis and endites together oval or heartshaped. Epignath without terminal spine. Pereopods relatively small in relation to body size. Pereopods 1 to 3 usually with one short spine and a short seta on propodus. Ischium of pereopods 4 to 6 usually with seta. Uropod basis and endopod fused and without exopod.
Type species: Metagathotanais insulcatus Bird & Holdich, 1988