Synonymy: Nannoniscella Hansen, 1916: 84.
Type species: Austroniscus ovalis Vanh ̂ffen, 1914
Diagnosis (modified from Kaiser & Brandt 2007): Body flattened and broadened; pereon and pleotelson expanded laterally in flat, marginal flanges. Pereonites without ventral spines. Rostral crest often well developed. Marginal flanges of pereonites 1–4 anteriorly produced. Antennula with 6 articles (only A. chelus Kaiser & Brandt, 2007, and male of Austroniscus brandtae n. sp. with 7 articles), terminal article unspecialised, not enlarged. Pereopod I somewhat shorter and distally more robust than pereopods II–VII; pereopods V–VII not especially expanded for swimming, with few natatory setae. Pleotelson without posterolateral spines. Operculum rectangular, covering a small part of the pleotelson ventral surface, width less than half pleotelson width, without ventral spines. Uropods hardly projecting above posterior margin, biramous, endo- and exopod almost of same length.
Composition: A. acutus Birstein, 1970; A. brandtae Kaiser, Stransky & Brix n. sp., A. chelus Kaiser & Brandt, 2007; A. coronatus Schiecke & Modigh-Tota, 1976; A. groenlandicus (Hansen, 1916); A. karamani Birstein, 1962; A. norbi Svavarsson, 1982; A. obscurus Kaiser & Brandt, 2007; A. ovalis Vanh ̂ffen, 1914; A. rotundatus Vanh ̂ffen, 1914; A. vinogradovi (Gurjanova, 1950).
Distribution: Arctic, Antarctic, Atlantic, Mediterranean, and North Pacific oceans, shelf to hadal (Figs 1, 6).