Borealia sanamyanae, Korshunova, Tatiana, Martynov, Alexander, Bakken, Torkild, Evertsen, Jussi, Fletcher, Karin, Mudianta, I Wayan, Saito, Hiroshi, Lundin, Kennet, Michael Schroedl, & Picton, Bernard, 2017

Korshunova, Tatiana, Martynov, Alexander, Bakken, Torkild, Evertsen, Jussi, Fletcher, Karin, Mudianta, I Wayan, Saito, Hiroshi, Lundin, Kennet, Michael Schroedl, & Picton, Bernard, 2017, 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, pp. 1-139 : 23

Borealia sanamyanae sp. n. Fig. 17

Type material.

Holotype, ZMMU Op-518, 5 mm long (fixed), Middle Kurile Islands, Matua Island, Cape Klyuv, 25.08.2016, depth 17 m, coll. N.P. Sanamyan.

Type locality.

North West Pacific, Middle Kurile Islands.

Etymology.

In honour of Nadezhda Sanamyan, marine biologist from Kamchatka. She has made a considerable contribution in collecting North West Pacific nudibranchs.

Diagnosis.

Continuous notal edge, background colour translucent white, digestive gland diverticula dark-red to pinkish, apical parts of cerata with white pigment, radula consists of more than 24 teeth, rachidian tooth with up to seven distinct denticles adpressed to central cusp, lateral teeth with few denticles on teeth edge.

Description.

External morphology (Fig. 17 A–C). Body relatively wide. Foot and tail moderate, anterior foot corners relatively short. Rhinophores similar in size to oral tentacles, slightly wrinkled, robust. Dorsal cerata fusiform, long, continuously attached to rudimentary but uninterrupted notal edge without forming clusters. Apices of cerata pointed. Notum narrow but distinct throughout both lateral sides of body. Digestive gland diverticulum fills significant volume of cerata. Anal opening on right side below notal edge in first half of body but closer to middle. Reproductive openings lateral, below notal edge around middle part of body.

Colour (Fig. 17A). Background colour translucent white. Digestive gland diverticula dark-red to pinkish. Apical parts of cerata with opaque cap of white pigment.

Jaws (Fig. 17 D–F). Masticatory process more than one-third as long as jaw body. Edge of masticatory processes bears ca. 20 denticles that continue to form several reduced rows of denticles on body of masticatory processes.

Radula (Fig. 17G). Radula formula: 24 × 1.1.1. Rachidian tooth elongate-triangular with small narrow cusp. Rachidian tooth bears 5-7 well-defined separated lateral denticles. Cusp is adpressed by adjacent first lateral denticles. Lateral teeth broadly triangular with obtuse and distinctly attenuated posteriorly outer process and between six and nine sharp long denticles on internal edge.

Reproductive system (Fig. 17H). The available material contains only a non-mature reproductive system, which do not allow recognition of characters in detail.

Ecology.

Shallow waters, stony and rocky habitats.

Distribution.

Northwest Pacific.

Remarks.

According to the molecular phylogenetic analysis Borealia sanamyanae sp. n. forms a separate sister clade to B. nobilis (Fig. 1). The following morphological characters distinguish B. sanamyanae sp. n. from B. nobilis : larger number of radular rows (max up to 22 in 40-50 mm length B. nobilis ( Kuzirian 1979); our specimens from the White and Barents Seas are about 20-30 mm in length and have max 20 rows, whereas a ten times smaller 5-mm specimen of B. sanamyanae sp. n. has 24 rows), and the cusp of the central tooth in B. nobilis , though relatively low, is almost not adpressed by the adjacent lateral denticles (Fig. 16H), whereas in B. sanamyanae sp. n. it is considerably adpressed (Fig. 17G).