Austroniscus Vanhöffen, 1914

Kaiser, Stefanie, Stransky, Bente, Jennings, Robert M., Kihara, Terue Cristina & Brix, Saskia, 2023, Combining morphological and mitochondrial DNA data to describe a new species of Austroniscus Vanhöffen, 1914 (Isopoda, Janiroidea, Nannoniscidae) linking abyssal and hadal depths of the Puerto Rico Trench, Zootaxa 5293 (3), pp. 401-434 : 414-415

Austroniscus Vanhöffen, 1914

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 ).

Figures

FIGURE 1. A) Global distribution of Austroniscus Vanĥffen, 1914 (Crustacea, Isopoda) species (only type localities shown); 1) A. acutus Birstein, 1970; 2) A. chelus Kaiser & Brandt, 2007; 3) A. brandtae Kaiser, Stransky & Brix n. sp.; 4) A. coronatus Schiecke & Modigh-Tota, 1976*; 5) A. groenlandicus Hansen, 1916*; 6) A. karamani Birstein, 1962; 7) A. norbi Svavarsson, 1982; 9) A. ovalis Vanĥffen, 1914*; 10) A. rotundatus Vanĥffen, 1914*; 11) A. vinogradovi Gurjanova, 1950; *the exact coordinates of the type locality were not given in the description of these species, therefore the position shown is assumed here on the basis of the original literature. B) Map of the sampling area of Austroniscus brandtae Kaiser, Stransky & Brix n. sp. in the Puerto Rico Trench abyss and hadal.

FIGURE 6. Bathymetric (A) and geographic distribution (B) of described Austroniscus species; 1) A. acutus Birstein, 1970; 2) A. chelus Kaiser & Brandt, 2007; 3) A. brandtae Kaiser, Stransky & Brix n. sp.; 4) A. coronatus Schiecke & Modigh-Tota, 1976; 5) A. groenlandicus Hansen, 1916; 6) A. karamani Birstein, 1962; 7) A. norbi Svavarsson, 1982; 8) A. obscurus Kaiser & Brandt, 2007; 9) A. ovalis Vanĥffen, 1914; 10) A. rotundatus Vanĥffen, 1914; 11) A. vinogradovi Gurjanova, 1950. Taxonomy and depth ranges in accordance with WoRMS (WoRMS Editorial Board 2021).