Gulenia monicae, 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

Gulenia monicae sp. n. Fig. 26

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

Non Aeolis lineata Lovén, 1846: 8.

Type material.

Holotype, ZMMU Op-466, 34 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 17.03.2015, depth 29-30 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-408, 23.5 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 17.03.2015, depth 20 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-411, 24.5 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 17.03.2015, depth 10-20 m, coll. T.A. Korshunova, A.V. Martynov. 1 paratype, ZMMU Op-475, 25 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-475, 31 mm long (live), Norway, entrance of the Sognefjord, Gulen Dive Resort, 02.04.2016, 25-30 m depth, coll. T.A. Korshunova, A.V. Martynov.

Type locality.

Gulen Dive Resort, Norway.

Etymology.

After Monica Bakkeli, proprietor of the Gulen Dive Resort, who significantly helped in organizing the scientific meetings and collecting activities in Gulen.

Diagnosis.

Continuous notal edge, background colour translucent white, digestive gland in cerata orange-brown to reddish-brown, 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 central cusp, lateral teeth with up to 18 denticles on teeth edge, penis is broad lobe.

Description.

External morphology (Fig. 26 A–E). Body relatively narrow. 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, short, 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 the cerata. Anal opening on right side below notal edge in first half of body but closer to middle. Reproductive openings lateral, below notal edges around middle part of body. Tail short and pointed, extending only short distance beyond last cerata.

Colour (Fig. 26A). Background colour translucent white. Digestive gland diverticula orange-brown to reddish-brown. Thick opaque white line runs along 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 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 ceratal surfaces. Apical parts of cerata without opaque cap of white pigment.

Jaws (Fig. 26F, G). Masticatory process more than one-third as long as jaw body. Edge of masticatory processes bears about 60-80 denticles that continue to form several reduced rows of denticles on the body of the masticatory processes.

Radula (Fig. 26H). Radula formula: 16-17 × 1.1.1. Rachidian tooth elongate-triangular with very strong cusp of nearly 1/3 of the tooth length (Fig. 26H). Rachidian tooth bears eight or nine well-defined separated (but adpressed towards the cusp) long lateral denticles. Cusp delineated from the adjacent first lateral denticles. Lateral teeth (Fig. 26H) narrowly triangular with obtuse and distinctly attenuated posteriorly outer process and between 13 and 18 sharp long denticles on internal edge.

Reproductive system (Fig. 26I, J). Diaulic. Hermaphroditic duct leads to convoluted ampulla of about two whorls. Vas deferens very short, not attached to dorsal side of the penial sheath, no distinct prostate. Penial sheath large, wide. Penis is broad lobe. Oviduct connects through insemination duct into female gland complex. Vagina short and indistinct. Proximal and distal receptaculum seminis placed relatively close to each other (Fig. 26J).

Ecology.

Associates with the Tubularia colonies usually at depth 20-30 m. Feeds on small athecate hydroids and Eudendrium spp. which grow on the stalks of the Tubularia and the adjacent rock surfaces. This species is locally abundant. Egg mass is a narrow spiral cord. Reproduction period from February to May; 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.

According to the present molecular phylogenetic analysis Gulenia monicae sp. n. forms a separate clade within the genus Gulenia , sister to G. orjani sp. n. The genetic distance of the mitochondrial barcode marker (COI) separates sympatric G. monicae sp. n. with high genetic divergence (11.3%). The mean COI p-distance value within the G. monicae sp. n. clade (5 specimens) is 0.45% and within the G. orjani sp. n. clade (14 specimens) is 0.41%. While this species shows a considerable minimal COI p-distance (10.97 ± 1.2%) compared to G. orjani sp. n., morphologically it is difficult to distinguish. G. monicae sp. n. can be tentatively distinguished externally from G. orjani sp. n. by a narrower body and shorter cerata.