Dendronotus nordenskioeldi Korshunova & Bakken & GrØtan & Johnson & Lundin & Martynov 2021, sp. nov.

• Main Authors: Korshunova, Tatiana, Bakken, Torkild, GrØtan, Viktor V., Johnson, Kjetil B., Lundin, Kennet, Martynov, Alexander
• Format: Text
• Language: unknown
• Published: Zenodo 2020
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Gastropoda; Nudibranchia; Dendronotidae; Dendronotus; Dendronotus nordenskioeldi; Arctic; Laptev Sea; Nils; Bakken; Grøtan; laptev
• Online Access: https://dx.doi.org/10.5281/zenodo.4623951; https://zenodo.org/record/4623951

Dendronotus nordenskioeldi sp. nov. Figs 1–3, 5–7 ZooBank: http:// urn:lsid:zoobank.org:act: 9FB63088-BF8A-4990-B292-7E26DEA0FDCF Etymology . In honour of Baron Nils Adolf Erik Nordenskiöld, outstanding Arctic explorer, geologist, and mineralogist. The Laptev Sea had been originally named “Nordenskiöld Sea”, after this Arctic explorer. Type locality . Laptev Sea. Type material . Holotype. ZMMU Op-665. Arctic region, Laptev Sea, sta. 100, 69 m depth, collector Olga Zimina. Description . Body relatively narrow, preserved holotype 19 mm length (fig. 5). Fiveto six main branched appendages on oral veil. Five appendages on rhinophoral stalks; 12–14 rhinophoral lamellae. Lateral papilla on rhinophoral sheath present. Five pairs of dorsolateral appendages. Circa 20 lip papillae. Dorsolateral appendages with relatively short primary stalk, moderately branched secondary branchesandtertiarybranches (fig. 5A, B). Basal colour is semitranslucent white. No additional pigment. Dorsal processes of jaws inclined posteriorly at approximately 53° to the longitudinal axis of the jaw body and 0.42 of its length (fig. 5D). Masticatory border of jaw with fine denticles (fig. 5E). Radular formula: 43 × 3– 11.1.11 –3. Central (rachidian) tooth bears very weak denticulation that are difficult to separate into individual denticles (up to 20 and more variously varied denticles at least) (fig. 5F, G). Denticles without deep furrows.Lateralteeth elongate, slightly curved, bearing up to seven denticles (+ 2–3 reduced denticles may present) (fig. 4F–H). Ampulla thickened, kidney-shaped. Prostate discoidal, consisting of up to 20 alveolar glands. Distal part of vas deferens moderate in length, transitioning to long, thick, curved copulatory organ. Bursa copulatrix large, distinctly elongated, with seminal receptaculum placed distally. Distribution . So far known only from the Laptev Sea. Remarks. Externally, Dendronotus nordenskioeldi sp. nov. resembles white forms of D. lacteus but differs by the absence of a distinct reticulation and peculiar ribs on the central teeth, which is a common characteristic of D. lacteus (Korshunova et al., 2017a). According to the molecular differences, a minimal intergroup distance for the COI gene (7.9%) is found between D. nordenskioeldi sp. nov and D. europaeus . The mean intergroup distances between D. nordenskioeldi sp. nov. and D. rufus, D. lacteus, and D. kamchaticus are 8.3%, 8.3%, and 8.8% respectively. Amaximal intergroup distance (15.0%) is found between D. nordenskioeldi sp. nov and D. patricki (Appendix, table A2). Synopsis of the previously described valid taxa of the family Dendronotidae : Published as part of 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, pp. 93-153 in Contributions To Zoology 90 (1) on pages 104-106, DOI: 10.1163/18759866-BJA10014, http://zenodo.org/record/4623915 : {"references": ["Korshunova, T., Martynov, A., Bakken, T., Evertsen, J., Fletcher, K., Mudianta, I., Saito, H., Lundin, K., Schrodl, M. & Picton, B. (2017 a) Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda). ZooKeys, 717, 1 - 139."]}