Cryosignum, Just & Wilson, 2007

Just, Jean & Wilson, George D. F., 2021, Redescriptions and new species in the ‘ Austrosignum-Munnogonium’ complex sensu Just & Wilson (2007), mainly from the Southern Hemisphere (Crustacea Isopoda: Paramunnidae), Zootaxa 4952 (3), pp. 401-447 : 410

Key to species of Cryosignum

1. Pereionite 1–7 dorsal surface smooth; antennula article 1 length subequal to article 2, or longer than article 2............ 2

- Pereionite 1–7 dorsal surface with transverse ridges; antennula article 1 shorter than article 2......................... 3

2. Head frontal margin nearly straight with angular corners; pereionites 1–7 lateral margin rounded, smooth; pleotelson lateral margin with proximal neck before convex margin; antennula articles 3 and 5–6 of subequal length, longer than article 4............................................................................ Cryosignum nordenstami sp. nov.

- Head front margin broadly convex, without angular corners; pereionite 1 lateral margin broadly rounded with small concavity; pereionite 1–4 lateral margins denticulate; pleotelson lateral margin convex; antennula articles 5–6 of subequal length, longer than articles 3–4....................................................... Cryosignum latifrons ( Menzies, 1962)

3. Head frontal margin nearly straight laterally, with angular lateral corners adjacent to antennae; eyestalks shaft constricted proximally; pleotelson laterally rounded, with inflection between proximal and lateral margins.............................................................................................. Cryosignum incisum ( Richardson, 1908)

- Head frontal margin broadly rounded, without angular lateral corners adjacent to antennae; eyestalks shaft before apex approximately parallel; pleotelson laterally rounded with inflection and distinct neck between lateral and proximal margins............................................................................... Cryosignum lunatum ( Hale, 1937)