Paracoryphella ignicrystalla, 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 : 14

Paracoryphella ignicrystalla sp. n. Fig. 8

Type material.

Holotype, ZMMU Op-490, 11.5 mm long (fixed), The Sea of Japan, Vostok Bay, intertidal, 17.03.1994, coll. A.V. Martynov. 1 paratype, ZMMU Op-491, 5 mm long (fixed, dissected), The Sea of Japan, Vostok Bay, intertidal, 14.03.1994, coll. A.V. Martynov. 1 paratype, ZMMU Op-492, 12 mm long (fixed, dissected), The Sea of Japan, Vostok Bay, intertidal, 18.02.1990, coll. A.V. Martynov.

Type locality.

The Sea of Japan, Vostok Bay.

Etymology.

From igni (= fire, Latin) and crystallum (= ice, rock crystal, Latin), in reference to the double combination of peculiar morphological and ecological features: short flame-like cerata with icy speckles on dorsum and peculiar environmental characteristics of the type locality which combines icy sea water temperatures (down to -2 °C) in winter and warm subtropical conditions in summer (water temperature up to +26 °C) as an allusion to the George R. R. Martin "A Song of Ice and Fire" novels.

Diagnosis.

Continuous notal edge, colour translucent white with scattered opaque white dots, cerata orange-brown to reddish-brown, rachidian tooth with up to 12 denticles not clearly delineated from relatively low central cusp, lateral teeth with few distinct basal denticles, distal receptaculum seminis, penis not internal, permanently attached externally.

Description.

External morphology. Body wide. Foot and tail wide, anterior foot corners short. Oral tentacles long. Rhinophores ca. 1.5 times shorter than oral tentacles, smooth to slightly wrinkled. Dorsal cerata fusiform, relatively short, continuously attached to well-defined 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 the cerata. Anal opening on right side below notal edge close to middle body part. Reproductive openings lateral and non-retractable penis below second ceratal row. Tail short and pointed, extending only a short distance beyond last cerata.

Colour (Fig. 8A). Background colour translucent white. Digestive gland diverticula orange-brown to reddish-brown. Small opaque white spots cover the entire dorsum, commonly on ceratal bases and less on cerata. Rhinophores and oral tentacles similar in colour to body; apical parts covered with opaque white pigment. Apical parts of cerata without opaque cap of white pigment.

Jaws (Fig. 8E). Masticatory process more than one-third as long as jaw body. Edge of masticatory processes bears ca. 40-50 denticles that continue to form several reduced rows of denticles on the body of the masticatory processes.

Radula (Fig. 8F, H). Radula formula: 10-12 × 1.1.1(2-3). Rachidian tooth elongate-triangular with strong non-compressed cusp of nealy 1/3 of the tooth length (Fig. 8G). Rachidian tooth bears up to 15 well-defined separated (but adpressed towards the cusp) long lateral denticles. Cusp is not clearly delineated from the adjacent first lateral denticles. Lateral teeth (Fig. 8F, H) narrowly triangular with peculiar widened base and few indistinct denticles on internal edge. There are one to three rudimentary additional lateral teeth on the right side only.

Reproductive system (Fig. 8I, J). Diaulic. Hermaphroditic duct leads to strong convoluted ampulla of about two whorls. Vas deferens is relatively long, no distinct prostate. No penial sheath. Penis is attached to the external body wall, vas deferens enters the base of penis from the internal side. Oviduct connects through insemination duct into female gland complex. Vagina short and indistinct. Distal receptaculum seminis.

Ecology.

Stony intertidal to 5-6 m. Feeds on athecate solitary hydroids. This species is locally abundant. Egg mass is white to pinkish narrow cord. Reproduction period from December to April. Development is about one month. The larva is a planktotrophic veliger with spiral shell.

Distribution.

Northwest part of the Sea of Japan.

Remarks.

Paracoryphella ignicrystalla sp. n. clearly differs from the type species of the genus P. islandica (Fig. 9K, H) in having considerably shorter cusps of the rachidian teeth (Fig. 8F, G). We have not yet obtained molecular data for this Sea of Japan Paracoryphella , but regard the morphological differences sufficient to warrant a new species.