Ekimova I.A.1,2, Schepetov D.M.3,4,5, Chichvarkhina O.V.6, Chichvarkhin A.Yu.2,6 2016. Nudibranch molluscs of the genus Dendronotus Alder et Hancock, 1845 (Heterobranchia: Dendronotina) from Northwestern Sea of Japan with description of a new species // Invertebrate Zoology. Vol.13. No.1: 15–42 [in English].
1 Biological Faculty, Moscow State University, Leninskiye Gory 1-12, 119234 Moscow, Russia. E-mail: firstname.lastname@example.org
2 Far Eastern Federal University, Sukhanova Str. 8, 690950 Vladivostok, Russia.
3 Koltzov Institute of Developmental Biology RAS, Vavilov Str. 26, 119334 Moscow, Russia.
4 Russian Federal Research Institute of Fisheries and Oceanography, Verkh. Krasnoselskaya Str. 17, 107140 Moscow, Russia.
5 National Research University Higher School of Economics, Myasnitskaya Str. 20, 101000 Moscow, Russia.
6 A.V. Zhirmunsky Institute of Marine Biology, Russian Academy of Sciences, Palchevskogo Str. 17, 690041 Vladivostok, Russia.
ABSTRACT: Species of the genus Dendronotus are among the most common nudibranchs in the northern Hemisphere. However, their distribution and composition in the North-west Pacific remain poorly explored. In the present study, we observed Dendronotus composition in northwestern part of the Sea of Japan, using an integrative approach, included morphological and molecular phylogenetic analyses and molecular species delimitation methods. These multiple methods revealed high cryptic diversity within the genus. Two specimens of Dendronotus frondosus were found in Amursky Bay and therefore its amphiboreal status was confirmed. In three locations of the Sea of Japan we found specimens, which are very close externally to D. frondosus, but show significant distance according to molecular analysis. We show that these specimens belong to a new species Dendronotus dudkai sp.n. This species is sister to D. frondosus according to morphological and molecular data, therefore the question of sympatric coexistence is discussed. For the first time Dendronotus kamchaticus was registered in the Sea of Japan and updated information of some intraspecific variation of this species is provided.
KEY WORDS: Nudibranchia, northwestern Pacific, species delimitation, molecular phylogeny, integrative taxonomy, Mollusca.