Key to genera and subgenera in the Janirellidae

1. Cephalon with true rostrum, or pseudorostrum derived from frons/clypeus; front margin between antennulae> 2 times width of antennula base; posterior margin of pleotelson projecting between uropods; uropods normally> 0.2 length of pleotelson...................................................................................................2

- Cephalon front without rostrum or pseudorostrum, front margin between antennulae equal to width of antennula base; posterior margin of pleotelson an even convex curve between uropods; uropods> 0.7 length of pleotelson ................................................................................................................... Dactylostylis

2. Cephalon with true rostrum, simple or complex; body generally fusiforme, with lateral spines (for exceptions see Discussion).................................................................................................................... 3 Janirella

- Cephalon with distinctive pseudorostrum; body flattened, body margins parallel, pereonites laterally truncate without spines ............................................................................................................. Triaina gen. nov.

3. Pleotelson with several lateral projections; lateral projections of pereonites setiferous ............. ( Janirella)

- Pleotelson with single lateral projection; lateral projections of pereonites without setae ............................. .........................................................................................................................( Parjanirella Birstein, 1971)