Myja karin
- Dataset
- The extraordinary genus Myja is not a tergipedid, but related to the Facelinidae s. str. with the addition of two new species from Japan (Mollusca, Nudibranchia)
- Rank
- SPECIES
- Published in
- Martynov, Alexander, Mehrotra, Rahul, Chavanich, Suchana, Nakano, Rie, Kashio, Sho, Lundin, Kennet, Picton, Bernard, Korshunova, Tatiana (2019): The extraordinary genus Myja is not a tergipedid, but related to the Facelinidae s. str. with the addition of two new species from Japan (Mollusca, Nudibranchia). ZooKeys 818: 89-116, DOI: http://dx.doi.org/10.3897/zookeys.818.30477, URL: http://dx.doi.org/10.3897/zookeys.818.30477
Classification
- kingdom
- Animalia
- phylum
- Mollusca
- class
- Gastropoda
- order
- Nudibranchia
- family
- Tergipedidae
- genus
- Myja
- species
- Myja karin
biology_ecology
Biology. Subtidal, on stony and rocky area with the hydroids Pennaria sp. (Fig. 2 F). Egg mass is a long, convoluted ribbon (Fig. 2 D). Veligers are planktonic, with turbospiral shell (Fig. 2 G, H).
description
Description. Body very elongate, holotype ca. 12 mm alive (Fig. 2 A-D). Rhinophores ca. 1.5 times longer than oral tentacles, smooth. Dorsal papillae cylindrical to spindle-shaped, forming nine or ten ceratal rows along dorsal edges. Apices of papillae form moderate oval swellings, without cupola-shaped appendage (Fig. 2 E). Notal edge absent. Anal opening acleioproctic on right side before first posterior ceratal rows. Reproductive openings lateral, below first anterior and second posterior rows of cerata. Ground colour translucent greyish. Oral tentacles and rhinophores with scattered opaque white dots. On head after oral tentacles shines a small pinkish area, lateral sides of head with thin streaks of brown-orange pigment. Opaque white spots in anterior part of the body behind rhinophores absent. Between rhinophores shines a large brownish area. Digestive gland in the cerata (ceratal cores) whitish to light creamy and light greyish (basal parts can be very pale greenish), digestive gland in upper part of cerata with dull pinkish-brownish internal spot, apices mostly translucent with small white band at very tip. Anterior cerata with prominent brownish basal spot. A spot similar in colour, but duller brownish and smaller in size, may occur at basal part of other cerata. Central branches of digestive gland shine through dorsal part of body and are brownish with few greyish parts. Numerous, moderately dense, small, white gonads appeared as white spherules that shine through dorsal surface. Jaws broadly triangular with prominent anterior wings, masticatory borders smooth (Fig. 2 I, J). Radula uniserial, very small compared to the pharynx internal volume (Fig. 2 K). Radular formula 17 x 0.1.0. Central tooth narrowly triangular with very sharp top and up to ca. 20 - 30 (and probably more) small denticles, irregular in size (Fig. 2 L-N), often hard to delineate with very distinct dorsal denticle furrows and fine rib-like structures (Fig. 2 M, N). Reproductive system diaulic (Fig. 4 B). Ampulla moderate in size, slightly widened in the middle (Fig. 4 B, am). Vas deferens short, without distinct prostatic portion (Fig. 4 B, vd), penial sheath widened (Fig. 4 B, psh), penis unarmed, with at least two unequal elevations (Fig. 4 B, p). Single proximal receptaculum seminis very large, elongated (Fig. 4 B, rsp).
diagnosis
Diagnosis. Up to ten ceratal rows, ground colour translucent greyish, ceratal cores light to dark greyish, ceratal tops dull reddish, apices with white spot, anterior cerata with brownish basal spot, no sparse white spots in the first half of the dorsal part, white gonad spherules moderately dense, cerata moderately widened at top without smaller separate cupola-shaped tip, central tooth narrowly triangular with very sharp non-pitted top and numerous lateral denticles, up to 20 - 30 small irregular in size denticles, very distinct ridges and furrows on the teeth surface, no accessory penial gland, penis unarmed.
distribution
Distribution. Central parts of the Pacific coast of the main Japanese island of Honshu; potentially can occur at least at the southern parts of Honshu and Kyushu.
etymology
Etymology. In honour of Karin Fletcher (Port Orchard, Washington), who has made considerable recent efforts in uncovering hidden diversity and understanding of the nudibranch fauna of the NE Pacific.
Name
- Homonyms
- Myja karin