Dendronotus albus MacFarland, 1966, 1970

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 : 112-113

Dendronotus albus MacFarland, 1966

Fig. 7

Dendronotusalbus MacFarland, 1966: 275– 279 , Pl. 40, Fig. 1 ; Pl. 46, Figs 1–4 ; Pl. 47, Figs 8 –11; Pl. 48, Figs 7 , 8 ; Pl. 49, Fig, 5; Pl. 50, Fig. 4 ; Pl. 51, Figs 6 , 7 .

Dendronotus diversicolor Robilliard, 1970: 470–474 , Figs 4–6 , 25–28, Pl. 64, Figs 35, 36.

Not D.albus sensu Robilliard, 1970:466–470 ; Behrens, 1980: 72; Behrens and Hermosillo, 2005: 93; McDonald, 1983: 172; McDonald, 2009: 463 = D. robilliardi Korshunova, Sanamyan, Zimina, Fletcher, Martynov, 2016 .

Extended diagnosis. Body relatively narrow. Four to five pairs of branched dorsolateral appendages, digestive gland penetrates only two pairs of dorsolateral appendages. Up to six appendages of oral veil. Three to seven appendages (external longest) of rhinophoral stalks. Lateral papilla of rhinophoral sheaths present. Rhinophoreswith 12–21 lamellae. Two to eight lip papillae. Basal colour translucent white to violet, dorsolateral appendage variable opaque orange or opaque white, including tip. Dorsalprocessesof jaws inclined posteriorly at approximately 50–60° to the longitudinal axis of the jaw body and 0.4–0.47 of its length. Masticatory borders apparently with ridge-like structures and denticles. Radula with up to 38 rows of teeth. Central tooth with up to 25 small distinct denticles without furrows. Up to nine lateral teeth with up to 14 denticles. Ampulla voluminous, folded. Bursa copulatrix large, oval. Seminal receptaculum very small and placed distally at a short distance from the vaginal opening. Prostate discoid with about 10–30 alveolar glands. The vas deferens is relatively short, bent, penis short, nearly straight, tapering to a blunt tip. Body length upto 73 mm.

Distribution. NE Pacific: California to southern Alaska, Canada and US. Records from Baja California, Mexico, need verification.

Bathymetry. Intertidal to at least 30 m depth.

Remarks. Dendronotusalbus has for almost 50 years persistently been confused with D. robilliardi . Despite this, D. albus is readily distinguished from D. robilliardi by the number of dorsolateral appendages (four to five in D. albus vs. five to eight in D. robilliardi ) and the number of dorsolateral appendages into which the digestive gland branches penetrate (only in two anterior pairs in D. albus vs. three to six pairs including posterior ones in D. robilliardi ). See Korshunova et al. (2016a) for discussion.

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 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 6 Reproductive systems. a, Dendronotus yrjargul sp. nov.; b, D.kalikal; c, D.elegans; d, D. nordenskioeldi sp. nov. Scale bars:a–d 1mm.Abbreviations:am, ampulla; bc, bursa copulatrix; fgm, female gland mass; fo, female opening; p, penis; pr, prostate; rs, receptaculum seminis; ud, uterine duct; vd, vas deferens; vg, vaginal duct.

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

FIGURE 8 Dendronotus elegans. External and internal morphology.a: living specimen ZMMU Op-713 from Greenland, near East Atlantic North American coast; b: jaw, same specimen; c; posterior part of radula, general overview,same specimen; d: close up of smooth central teeth, same; e: close up of lateral teeth, same; f:living specimen ZMMU Op-714 (as “D.niveus”) from the White Sea (subarctic); g: jaw, same specimen; h:masticatory edge of the jaws,same; i: posterior part of radula, general overview,same specimen; j: close up of smooth central teeth, same; k: living specimen ZMMU Op-715 from the Laptev Sea (Arctic); l: jaw, same specimen; m: posterior part of radula, close up of smooth central teeth, same; n: lateral teeth, same.o: discoid prostate with numerous alveols (which considerably exceed the considerably underestimated number presented in the first description of D.niveus), same specimen; Scale bars: b, l, 1mm; c: 300 µm; d, h–j, m: 100 µm; g: 1000 µm; e, n: 30 µm. PHOTOGRAPHS BY O. ZIMINA (A, K) AND T. KORSHUNOVA (F). SEM MICROGRAPHS BY A. MARTYNOV