Dendronotus frondosus

• 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 frondosus; Arctic; Barents Sea; White Sea; Greenland; Pacific; Norway; Rupert; Bakken; Grøtan; North Atlantic; North East Atlantic
• Online Access: https://dx.doi.org/10.5281/zenodo.4623976; https://zenodo.org/record/4623976

Dendronotus frondosus (Ascanius, 1774) Fig. 7 Amphitrite frondosa Ascanius, 1774: 155–158, Pl. 5, Fig. 2 (neotype selected in Ekimova et al. 2015). Dendronotusfrondosus (Ascanius, 1774) – Odhner, 1936: 1105–1109, Fig. 39 (mixture of several species); Robilliard, 1970: 441–446, Pl. 63, Fig. 29, textand Figs 4, 7, 8, 9 (partim, mostly referred to D. venustus ); Ekimova et al. 2015: 848–857, Figs 1–5, 6A, 7A, 8A. Doris arborescens Müller, 1776:229 (mixture of several species). Doris cervina Gmelin, 1791: 3105, no. 12. Tritonia reynoldsii Couthouy, 1838: 74–80, Pl. 2, Figs 1, 2, 3, 4. Tritonia felina Alder & Hancock, 1842: 33. Tritonia pulchella Alder & Hancock, 1842: 33–34. Tritoniaascanii MØller, 1842: 5. Amphitridea fabricii Kröyer, 1847: 114. Campaspe pusilla Bergh, 1863: 471–478, Pl. 12, Figs 28–35. Campaspe major Bergh, 1886: 21–24; Pl. 1, Figs. 23–26; Pl. 2, Figs 1 –11. Dendronotus luteolus Lafont, 1871: 267. Dendronotus junior Mörch, 1875: 125. Dendronotus arborescens var. aurantiaca Friele, 1879: 284. NB: Mixture of several species under the name Dendronotus frondosus in the literature before 2015. Extended diagnosis . Body narrow. Fiveto six pairs of branched dorsolateral appendages. Four to seven appendages of oral veil. Four to five appendages (middle and posterior ones can be longer) of rhinophoral stalks. Lateral papilla of rhinophoral sheaths present. Rhinophoreswith six to 12 lamellae. Lip papillae four to 12. Basal colour brownish to reddish-brown, often with small white and yellow specks, but usually without opaque white stripes between dorsolateral processes to completely white translucent specimens. Dorsal processes of jaws inclined posteriorly at approximately 60° to the longitudinal axis of the jaw body and 0.4 of its length. Masticatory processes apparently bear ridgelike structures and denticles. Radula with up to 42 rows of teeth. Central tooth with deep furrows and with up to 14 (common range 8–12) distinct denticles. Upto 10 (usually upto eight) lateral teeth with upto seven denticles. Ampulla voluminous, folded. Bursa copulatrix large, oval to rounded. Seminal receptaculum small placed distally at a moderately short distance from the vaginal opening. Prostate discoid with range 16–30 alveolar glands. The vas deferens is moderate in length, penis relatively long, curved. Common body length no more than 50 mm. Distribution . North Atlantic, both east and west parts, not distributed to the Arctic further than the easternmost border of the Barents Sea. Bathymetry . Intertidal to 20–30 m depth. Remarks . Three common North Atlantic shallow water species, namely D. europaeus Korshunovaet al., 2017b, D. frondosus (Ascanius, 1774), and D. lacteus , show an extremely similar range of habitus variation (see Korshunova et al., 2017b) and have been confused in older literature. Therefore, the verified distribution of D. frondosus can only be assessed using recent data (Korshunova et al., 2017b) thatcoversatleastthe North East Atlantic from Norway and also the Barents Sea and the White Sea to possibly France/ northern Spain. The range of D. frondosus does not extend further than the the true Arctic. Also, several deep-water records of D. frondosus (e.g., Odhner, 1939; Swennen, 1961; Thompson & Brown, 1984) most likely refer to D. lacteus , since according to our data D. frondosus was usually found shallower than 20–30 m depth. We have examined an extensive collection of various Dendronotus from the NW Pacific and NE Pacific and have so far not found any specimen from the North Pacific for which the identity could be confirmed as D. frondosus despite the presence of a few published records (e.g., Ekimova et al., 2016). In this respect, the common occurrence of true D. frondosus in the North Atlantic and the extreme rarity of D. frondosus in the North Pacific, with the simultaneous common presence in the North Pacific of other species formerly considered as “ D. frondosus ”, (e.g., D. kalikal , D. kamchaticus , D. primorjensis, D. venustus ), clearly suggests that true D. frondosus does not occur naturally in the North Pacific. Here, it is largely substituted by other species fromthe D. frondosus species complex. In particularly, D. primorjensis endemic to the Sea of Japan, is morphologically similar to D. frondosus and sister to it according to our molecular phylogenetic analysis (fig. 1). D. primorjensis has several traceable diagnostic features in radula and reproductive system (see Korshunova 2016a and Synopsis below). By such features and molecular data D. primorjensis could be excellent candidate for an example of a relict species, with close relatives with ranges extending to the Arctic, which afterwards formed a separate species, D. frondosus , in the North Atlantic. As a result of such an evolutionary history, D. primorjensis and D. frondosus are evidently naturally separated from from closely related North Pacific and North Atlantic species, because true D. frondosus does not occur in the Arctic. On the contrary, the potentially disrupted populations of D. frondosus in the North Atlantic and the North Pacific do not reveal morphological and molecular differences. Most reliable explanations for such an occurrence of few of so far known specimens of D. frondosus in the North Pacific can bean anthropogenic introduction or a mistake in the sorting or processing of collection material. Dendronotusfrondosus does not occur naturally in the North Pacific. In this study we also evidently show that the North Pacific D. kalikal and the North Atlantic and Arctic D. yrjargul sp. nov. are invariably placed in two distinct clades (figs 1–3) with stable distinct differences in external and internal morphology (fig. 4) and without any gene flow between each other. Dendronotus kalikal thus does not occur naturally in the North Atlantic. Apotential future introduction of some North Pacific species from the “ D. frondosus megacomplex” may take place, but so far there are no reliable records of any North Pacific species in the North Atlantic. At least recently, a case of evident anthropogenic transportation of the dendronotid Pseudobornella orientalis was reported from Japan or China to NE Pacific (Agarwal et al., 2017) (for taxonomy of Pseudobornella see below). Thus, most previous records of this species from the Northwest Pacific refer to one of three recently described species, D. kamchaticus Ekimova et al., 2015, D. kalikal Ekimova et al., 2015, or D. primorjensis Martynov et al., 2015, and in the Northeast Pacific, previous records refer to D. venustus Stout et al., 2010 or D. kamchaticus Ekimova et al., 2015 (see also Korshunovaet al., 2016a, b). : 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 118-120, DOI: 10.1163/18759866-BJA10014, http://zenodo.org/record/4623915 : {"references": ["Ascanius, P. (1774) Beskrivelse over en Norske sneppe og et sodyr. Det Kongelige Norske Videnskabelige Selskabs Skrifter Trondhejm, 5, 153 - 158.", "Ekimova, I., Korshunova, T., Schepetov, D., Neretina, T., Sanamyan, N. & Martynov, A. (2015) Integrative systematics of northern and Arctic nudibranchs of the genus Dendronotus (Mollusca, Gastropoda), with descriptions of three new species. Zool. J. Linn. Soc., 173, 841 - 886.", "Odhner, N. (1936) NudibranchiaDendronotacea - A revision of the system. Mem. Mus. R. Hist. Nat. Belg. (Ser. 2), 3, 1057 - 1128.", "Robilliard, G. (1970) The systematics and some aspects of the ecology of the genus Dendronotus. Veliger, 12, 433 - 479.", "Muller, O. F. (1776) Zoologiae Danicae. Prodromus seu animalium Daniae et Norvegiae ingenarum characteres, nomina, et synonyma imprimis popularium. Hallageriis, Havniae.", "Gmelin, J. (1791) In: Linnaeus (Ed.) Systema Naturae, per regna tria naturae. 13, 1, 6, 3103 - 3107, 3147 - 3148.", "Couthouy, J. (1838) Descriptions of new species of Mollusca and shells, and remarks on several Polypi found in Massachusetts Bay. Boston J. Nat. Hist., 2, 53 - 111.", "Alder, J. & Hancock, A. (1842) Descriptions of several new species of nudibranchous mollusca found on the coast of Northumberland. Ann. Mag. Nat. Hist., 9, 31 - 36.", "MOller, H. P. C. (1842) Index Molluscorum Groenlandiae. C. A. Reitzelii, Hafniae.", "Kroyer, H. N. (1847) Zoologisches. I. Aus Koniglichen Musaen. Amtlicher Bericht uber die Versammlung Deutscher Naturforscher und Arzte in Kiel, 24, 109 - 115.", "Bergh, R. (1863) Campaspe pusilla, en ny Slaegstform af Dendronotidernes Gruppe, samt Bemaerkninger om Dotidernes Familie. Naturhist. Tidsskr. Stiftet af Henrik Kroyer, 1, 471 - 483.", "Bergh, R. (1886) Die Nudibranchien. Gesammelt warhrend der fahrten des \" Willem-Barents \" in das Nordliche Eismeer. Bijdr. Dierk., 13, 1 - 37, pls. 1 - 3.", "Lafont, A. (1871) Note pour servir a la faune de la Gironde contenant la liste des animaux marins dont la presence a ete constatee a Arcachon pendant les annees 1869 - 70. Act. Soc. Linn. Bordeaux, 28, 237 - 280.", "Morch, O. (1875) Prodromus Faunae Molluscorum Groenlandiae,. In: Rupert Jones, T. (Ed.) Manual of the Natural History, Geology, and Physics of Greenland and the Neighbouring Regions, 2014 Edition, pp. 124 - 135. Cambride University Press, Cambridge.", "Friele, H. (1879) Catalog der auf der norwegischen Nordmeerexpedition bei Sptizbergen gefundenen Mollusken. Jahrb. Deutsch. Malakozool. Gesellsch., 6, 264 - 286.", "Korshunova, T., Martynov, A., Bakken, T. & Picton, B. (2017 b) External diversity is restrained by internal conservatism: New nudibranch mollusc contributes to the cryptic species problem. Zool. Scr., 46, 683 - 692.", "Odhner, N. (1939) Opisthobranchiate Mollusca from the western and northern coasts of Norway. Det Kongelige Norske Videnskabernes Selskabs Skrifter, 1, 1 - 93.", "Swennen, C. (1961) Data on distribution, reproduction and ecology of the nudibranchiate molluscs occurring in the Netherlands. Neth. J. Sea Res., 1, 191 - 240.", "Thompson, T. & Brown, G. (1984) Biology of Opisthobranch Molluscs (vol. 2). The Ray Society Publishing, London.", "Ekimova, I., Schepetov, D., Chichvarkhina, O. & Chichvarkhin, A. (2016) Nudibranch molluscs of the genus Dendronotus Alder et Hancock, 1845 (Heterobranchia: Dendronotina) from Northwestern Sea of Japan with description of a new species. Invertebr. Zool., 13, 15 - 42.", "Korshunova, T., Sanamyan, N., Zimina, O., Fletcher, K. & Martynov, A. (2016 a) Two new species and a remarkable record of the genus Dendronotus from the North Pacific and Arctic oceans (Nudibranchia). ZooKeys, 630, 19 - 42.", "Agarwal, M. (2017) First record of Dendronotus orientalis (Baba, 1932) (Nudibranchia: Dendronotidae) in the temperate Eastern Pacific. BioInvasions Rec., 6, 135 - 138.", "Martynov, A., Ishida, Y., Irimura, S., Tajiri, R., O'Hara, T. & Fujita, T. (2015 b) When ontogeny matters: a new Japanese species of brittle star illustrates the importance of considering both adult and juvenile characters in taxonomic practice. PLOS ONE, 10, e 0139463.", "Stout, C., Pola, M. & Valdes, A. (2010) Phylogenetic analysis of Dendronotus nudibranchs with emphasis on northeastern Pacific species. J. Mollus. Stud., 76, 367 - 375."]}