Dendronotus bathyvela Martynov, Fujiwara, Tsuchida, R. Nakano, N. Sanamyan, K. Sanamyan, Fletcher & Korshunova, 2020

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 : 113-114

Dendronotus bathyvela Martynov, Fujiwara, Tsuchida, R. Nakano, N. Sanamyan, K. Sanamyan, Fletcher & Korshunova, 2020

Fig. 7

Dendronotusbathyvela Martynov et al. 2020a: 507–510 , Figs 4 , 5 .

Extended diagnosis. Body wide. Six to seven pairs of branched dorsolateral appendages. 10 to 15 appendages of oral veil. Five appendages of rhinophoral stalks. Lateral papilla of rhinophoral sheaths absent. Rhinophores with 15–25 lamellae. Lip papillae 50–70. Basal colour dull reddish-brownish with numerous distinct opaque white dots on notum, tips of lateral appendages, oral appendages. Dorsal processes of jaws inclined posteriorly at approximately 52° to the longitudinal axis of the jaw body and 0.56 of its length. Masticatory processes apparently bear indistinct denticles (may possess ridge-like structures). Radula with upto 41 rows of teeth. Central tooth with high cusp and up to 35 small distinct denticles without furrows. Up to 14 lateral teeth without or with few weak lateral denticles. Ampulla voluminous, with approximately three loops. Bursa copulatrix large, rounded to oval. Seminal receptaculum small placed distally at a short distance from the vaginal opening. Prostate discoid with about 21–25 alveolar glands. The vas deferens is long, penis elongate, narrow, curved. Body length upto 45 mm.

Distribution. Pacific coast of Northern Honshu, Japan, possibly may occur further in NW Pacific.

Bathymetry. Ashelf to deep-sea (bathyal) species, so far recorded at depths of 249– 510 m.

Remarks. This species has recently been described by Martynov et al. (2020a). Until recently, only the single species D. robustus was recognized among the wide-bodied, shallow-water dendronotids of the North Atlantic and the North Pacific shelf ( Ekimova et al.,2015).However, mostrecentdata showed that “ D. robustus ” is a species complex, which was already separated into D. robustus s.str., D. velifer and D. bathyvela ( Lundin et al., 2017; Martynov et al., 2020a).

Figures

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

FIGURE 7 Representaives of the genus Dendronotus (living specimens). PHOTOGRAPHS BY T. KORSHUNOVA, A. MARTYNOV, K. FLETCHER, D. MILLER, Y. FUJIWARA, K. HASEGAWA, K. SANAMYAN, N. SANAMYAN, AND O. ZIMINA