Fig. 4

Muusoctopus aegir Golikov, Gudmundsson & Sabirov, sp. nov. Beak and radula. a, d, paratype BS-70–1-2018 (pre-mature male, mantle length (ML) 29 mm, the Barents Sea): upper (a) and lower (d) beaks; b, e, KS-201–2010 (spent female, ML 52 mm, the Kara Sea): upper (b) and lower (e) beaks; c, f, BIOICE-2789 (early maturing male, ML 27 mm, off Iceland): upper (c) and lower (f) beaks; g, j, holotype BS-319–2012 (late maturing female, ML 43 mm, off the Barents Sea slope): older (g) and younger (j) unworn sections of radula; h, k, BS-255–2010 (mature male, ML 28 mm, off the Barents Sea slope): older (h) and younger (k) unworn sections of radula; i, BIOICE-2516–2 (late maturing female, ML 28 mm, off Iceland): older unworn section of radula. Scale bars: a–f = 1 mm, g–k = 100 µm. Abbreviations: l1, first lateral tooth; l2, second lateral tooth; m, marginal tooth; r, rachidian tooth