Cabangus regius ( Pola & Stout, 2008 ) Korshunova & Bakken & GrØtan & Johnson & Lundin & Martynov, 2021

Korshunova, Tatiana, Bakken, Torkild, GrØtan, Viktor V., Johnson, Kjetil B., Lundin, Kennet & Martynov, Alexander, 2021, A synoptic review of the family Dendronotidae (Mollusca: Nudibranchia): a multilevel organismal diversity approach, Contributions to Zoology 90 (1), pp. 93-153 : 133

Cabangus regius ( Pola & Stout, 2008) comb. nov.

Fig. 2

Dendronotus regius Pola & Stout, 2008: 46– 54 , Figs 1–5 .

Extended diagnosis. Body very narrow. Three to four pairs of branched dorsolateral appendages. Circa six appendages of oral veil. Four to five appendages (posterior ones longest) of rhinophoral stalks. Rhinophores with 10–11 lamellae. Lateral papilla of rhinophoral sheaths present. Lip papillae possibly absent. Basal colour white or yellow, with blue, brown and reddish patches. Masticatory processes with denticles. Radula with upto 36 rows of teeth. Central tooth with up to 20 small distinct denticles with furrows. Up to nine lateral teeth with up to seven denticles. Ampulla voluminous, folded. Bursa copulatrix large, pear-shaped to oval. Seminal receptaculum small placed distally at a short distance from the vaginal opening (in the original description entangled duct from ampulla was incorrectly identified as “receptaculum seminis”). Prostate non discoid, thickened, without evident alveolar glands.The vasdeferens ismoderate in length, penis tapered. Body length upto 15 mm.

Distribution. Tropical Indo-west Pacific.

Bathymetry. Up to 45 m deep.

Remarks. See under Cabangus gen. nov.

Figures

FIGURE 1 Phylogenetic relationships of the species of the genus Dendronotus based on COI + 16S + 28S + H3 concatenated dataset inferred by Bayesian Inference (BI). Numbers represent posterior probabilities from BI and bootstrap values for Maximum Likelihood.Some branches are collapsed at species level.Dendronotus elegans from the type region (North Atlantic) are highlighted in dark purple. Abbreviations:h – holotype; p – paratype.Summary of species delimitation results from ABGD analyses for the COI dataset is shown

FIGURE 2 Phylogenetic relationships of the species of the genera Dendronotus, Pseudobornella and Cabangus in single COI, 16S, 28S, and H3 gene trees inferred by Bayesian Inference (BI). Some branches are collapsed. Positions the Pseudobornella orientalis highlighted green; positions the Cabangus regius highlighted orange.Numbers represent posterior probabilities from BI. PHOTOGRAPHS BY A. MARTYNOV AND T. KORSHUNOVA

FIGURE 3 A.Map of the Northern Hemisphere showing the distribution of D.elegans (including “D.niveus”), D.kalikal, and D.yrjargul sp. nov.The type locality of D.elegans is indicated by crossed lines. B. The haplotype networks based on cytochrome c oxidase subunit I (COI), 16S rRNA (16S), and 28S rRNA (28S) molecular data showing genetic mutations occurring within D.elegans (“D.niveus”), D. kalikal, and D.yrjargul sp. nov. specimens.Abbreviations:BeSt – Bering Strait; BS – Barents Sea; Gr – Greenland; Km – Kamchatka; KS – Kara Sea; Ku – Kuril Islands; LS – Laptev Sea; Nf – Newfoundland; NS – Norwegian Sea; WS – White Sea.Type locality of D.elegans is marked on the map by “x”.

FIGURE 4 Dendronotus yrjargul sp.nov.(a–n) and D.kalikal (o–t), external and internal morphology.a–c: living holotype of D.yrjargul NTNU-VM-76306 (a) and its habitat (b, c), dorsal,ventral and lateral views with egg mass and associated hydroid Abietinaria fusca, respectively; d: Dendronotus yrjargul, habitat of living paratype NTNU-VM-76302;e: jaw of holotype; f:denticles on the masticatory edge of the holotype; g: jaws of paratype NTNU-VM-76302; h:discoid ridge-like structures on the masticatory edge of paratype NTNU-VM-76302;i: details of discoid structures on the masticatory edge of paratype NTNU-VM-76302; j: anterior part of radula of holotype; k:central teeth of radula of holotype;l:lateral teeth of radula of holotype; m:central teeth of radula of paratype NTNU-VM-76302; n: lateral teeth of radula of holotype; o: living holotype of D.kalikal; p: jaw of D.kalikal, specimen from Kurile Islands;

FIGURE 5 Dendronotus nordenskioeldi sp. nov.ZMMU Op-665, external and internal morphology.a–b:living holotype, dorsal and lateral views respectively;c:ventral view of preserved holotype;d: jaw of holotype; e: irregular denticles on the masticatory edge of the holotype;f:posterior part of radula; g:central teeth of radula; h: lateral teeth of radula of holotype.Scale bars: d: 1mm; e: 20 µm; f:100 µm; g, h: 30 µm. PHOTOGRAPHS BY O. ZIMINA (A, B) AND T. KORSHUNOVA (C). SEM MICROGRAPHS BY A. MARTYNOV