Gulenia orjani, 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 : 31-34

Gulenia orjani sp. n. Fig. 27

Flabellina lineata sensu Malmberg and Lundin 2015 (pars.): 88.

Non Aeolis lineata Lovén, 1846: 8.

Type material.

Holotype, NTNU-VM-72482, 22 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 19.03.2015, depth 20-30 m, coll. T.A. Kor shunova, A.V. Martynov. 1 paratype, ZMMU Op-407, 30 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 18.03.2015, depth 20 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-409, 27 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 18.03.2015, depth 20-30 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-410, 22 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 18.03.2015, depth 20-30 m depth, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-467, 35 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 02.04.2016, depth 10-15 m, coll. T.A. Korshunova, K. Malmberg, A.V. Martynov. 1 specimen, ZMMU Op-468, 19 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, depth 20-25 m depth, 03.04.2016, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-469, 33 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 02.04.2016, depth 20-25 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-470, 21 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 03.04.2016, depth 25-30 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-471, 19.5 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 05.04.2016, depth 20-30 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-472, 22.5 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 07.04.2016, depth 20-30 m, coll. T.A. Korshunova, B. Picton. 1 paratype, ZMMU Op-473, 32 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, depth 20-25 m, 03.04.2016, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-474, 32 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, depth 20-25 m, 03.04.2016, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-538, 19 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 19.03.2015, depth 20 m depth, coll. T.A. Korshunova, A.V. Martynov.

Type locality.

Gulen Dive Resort.

Etymology.

After Ørjan Sandnes, proprietor of the Gulen Dive Resort where the majority of the material for this study has been collected, who has been immensely supportive of this work.

Diagnosis.

Continuous notal edge, background colour translucent white, digestive gland in cerata orange-brown to reddish-brown, sometimes almost blackish, apical parts of cerata without white pigment, usually small white spots scattered on dorsal face of cerata, thick opaque white lines on dorsal and lateral sides, rachidian tooth with up to nine distinct denticles, not delineated from rachidian cusp, lateral teeth with up to 18 denticles on teeth edge, penis is a broad lobe.

Description.

External morphology (Fig. 27 A–E). Body relatively wide. Foot and tail moderate, anterior foot corners long. Oral tentacles long and robust. Rhinophores ca. 1.5 times shorter than 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. Tail short and pointed, extending only short distance beyond last cerata.

Colour (Fig. 27A). Background colour translucent white. Digestive gland diverticula orange-brown to reddish-brown, sometimes dark brown to blackish. Thick opaque white line runs down middle of whole dorsum from head to tail, varying in width and often spreading as lateral lobes amongst ceratal bases. Similar single thick median line runs on both lateral sides of the body. Rhinophores similar in colour to body; apical parts covered with opaque white pigment. Dorsal sides of oral tentacles covered with thick opaque white line. No line along dorsal face of cerata, instead small white dots and speckles scattered over the surfaces of cerata (Fig. 27F). Apical parts of cerata without opaque cap of white pigment.

Jaws (Fig. 27H, I). 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 body of the masticatory processes.

Radula (Fig. 27G). Radula formula: 16-19 × 1.1.1. Rachidian tooth elongate-triangular with very strong cusp of around 1/3 of the tooth length. Rachidian tooth bears eight or nine well-defined separated (but adpressed towards the cusp) long lateral denticles. Cusp strongly delineated from adjacent first lateral denticles. Lateral teeth narrowly triangular with obtuse and distinctly attenuated posteriorly outer process and between 13 and 18 sharp long denticles on internal edge.

Reproductive system (Fig. 27 J–L). Diaulic. Hermaphroditic duct leads to convoluted ampulla of about two whorls. Vas deferens very short, not attached to dorsal side of penial sheath, no distinct prostate. Penial sheath large, wide. Penis is a broad lobe (Fig. 27K). Oviduct connects through insemination duct into female gland complex. Vagina short and indistinct. Proximal and distal receptaculum seminis placed close to each other and similar in size (Fig. 27L).

Ecology.

Associates with the Tubularia colonies usually at depth 20-30 m. Feeds on small athecate hydroids growing on the Tubularia stems and the adjacent rock as well as on Eudendrium species. Egg mass is a narrow cord. Reproduction period from February to April; the larva is a planktotrophic veliger with oval shell.

Distribution.

In the Northeast Atlantic has been found only in Norway (present study) and possibly in Sweden.

Remarks.

Gulenia orjani sp. n. is readily distinguished morphologically from other superficially similar taxa of the family Coryphellidae (e.g., Fjordia lineata , F. chriskaugei ) as well as from the majority of the North Atlantic flabellinids by a combination of continuous notal edge with cerata not in clusters, a broad dorsal medial white line, and strong cusp of the rachidian radular tooth. Another distinctive feature of G. orjani sp. n. is absence of the white line on the dorsal surface of the cerata, which is substituted often by scattered white dots. The continuous notal edge resembles that in the genus Chlamylla ; the latter, however, is very different in having a distinct granulose prostate and complicated external penial collar. Two North Atlantic genera and species of the family Coryphellidae also possess a continuous notal edge, namely Gulenia borealis and Borealia nobilis . However, unlike G. orjani both these taxa do not possess dorsal and lateral continuous white lines and differ considerably in radular and reproductive morphology. Molecular analysis corroborates the morphological data (see Discussion). Colour may vary significantly. The reddish colour of the digestive diverticulum in the cerata is most common; however, specimens with light brown and even almost black diverticulum may occur. The medial white line also may vary to a considerable degree - including specimens with broad and narrow lines. White pigment spots on the cerata may be dense or almost absent. For differences from G. monicae sp. n. see above.