Dendronotus primorjensis Martynov, Sanamyan & Korshunova, 2015

Description

A medium-sized dendronotid with strong colour variation: from non-uniform reddish brown with opaque white stripes, to nearly uniform olive, to specimens almost lacking pigment. The dorsum and appendages bear scattered small whitish and yellowish dots. The dorsolateral cerata, oral veil appendages and rhinophoral sheath appendages are all branched and tree-like. There are 5-9 pairs of branched dorsolateral cerata, 5-12 oral veil appendages, 4-5 appendages on each rhinophoral stalk, and 8-12 lamellae on the rhinophore club. Living animals are usually 21-35 mm long. Radula formula in the holotype 37 × 8-9.1.9-8; the central tooth is robust with well-developed denticles on the cutting edge.

Distribution

Type locality: Spokoinaya Bay, north-western Sea of Japan (Primorye, Russian Far East), on stones, 6.5 m depth, 25 September 2014, T. A. Korshunova & A. V. Martynov leg. (holotype ZMMU Op-419). Distributed across the north-western Sea of Japan, with confirmed records on the Japanese side from Hokkaido. In their Распространение section Martynov et al. 2015 note that the species "is reliably known from the northern part of the Sea of Japan; possibly the range of this species is much wider and may cover all far-eastern seas of Russia, including the Commander Islands."

Etymology

The original Этимология paragraph (Martynov et al. 2015) is a single short line, translated verbatim from the Russian:

After the name of the type locality - Primorsky Krai

(the Maritime Province of the Russian Far East).

Remarks

Separated from the broadly defined North Atlantic / North Pacific Dendronotus frondosus complex on the basis of integrative morphological and molecular evidence. Northern-Japan animals reported by the 1957 study from off Muroran and Onagawa as "Dendronotus frondosus" most likely correspond to this species rather than to true D. frondosus. Dendronotus dudkai Ekimova et al., 2015 is treated as a junior synonym of Dendronotus primorjensis (Korshunova et al., 2016). In the Замечания, Martynov et al. 2015 state that "molecular-genetic analysis of the COI gene placed D. primorjensis at the base of the clade that includes the Atlantic species D. frondosus (Ascanius, 1774) and the Pacific species D. venustus MacFarland, 1966".

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References

• Dendronotus frondosus (Ascanius) Suginoha-umiushi, Baba, K. 1957. A revised list of the species of Opisthobranchia from the northern part of Japan, with some additional descriptions. J. Fac. Sci., Hokkaido Univ.,ser. 6, Zool. 13(1-4):8-14.
• 高岡生物研究会. (2002). 日本海のウミウシ. 第2版.
• スギノハウミウシ, 中野理枝. (2004). 本州のウミウシ. ラトルズ.
• Dendronotus primorjensis n.sp., Martynov A.V., Sanamyan N.P., Korshunova T. A. (2015). [in Russian] New data on the opisthobranch molluscs (Gastropoda: Opisthobranchia) of waters of Commander Islands and Far-Eastern seas of Russia. In: Conservation of biodiversity of Kamchatka and coastal waters. Proceedings of XV international scientific conference Petropavlovsk-Kamchatsky. Kamchat Press: Petropavlovsk-Kamchatsky, Russia. pp. 55-69, pl. 2-6.
• Dendronotus primorjensis Martynov, Sanamyan & Korshunova, 2015, 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. Zoological Journal of the Linnean Society. 173(4): 841-886.
• Korshunova T.A., Sanamyan N.P. & Martynov A.V. (2016). Morphological and molecular evidence indicate Dendronotus primorjensis is a valid species that has priority over D. dudkai (Nudibranchia). ZooKeys. 634: 15-28.
• オナガスギノハウミウシ（新称）, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.