Zelentia nepunicea, Korshunovа & Fletcher & Lundin & Picton & Mаrtynov, 2018

Korshunovа, Tаtiаnа, Fletcher, Kаrin, Lundin, Kennet, Picton, Bernаrd & Mаrtynov, Аlexаnder, 2018, The genus Zelentia is an amphi-boreal taxon expanded to include three new species from the North Pacific and Atlantic oceans (Gastropoda: Nudibranchia: Trinchesiidae), Zootaxa 4482 (2), pp. 297-321 : 305-308

Zelentia nepunicea sp. nov.

( Figures 1–2 , 4 , 7B )

http://zoobank.org/B01C7А9E-А949-4F54-89F9-34D64C6ECDF9

Cuthona pustulata sensu Gosliner & Millen 1984: 183 –187, figs 1–4; Behrens 1991: 94; Behrens, Hermosillo 2005: 129; Cella

et al. 2016: 10, 19, 26, supplementary fig. s002, Tenellia pustulata: Cella et al. 2016: 7 , 9, fig. 2, 16 non Eolis pustulata Alder & Hancock, 1854 Cuthona punicea sensu Cella et al. 2016: 10 , 19, 26, supplementary fig. s002 non Cuthona punicea Millen, 1986

Type Material. Holotype, ZMMU Op- 626, 12 mm in length (live), NE Pacific, Canada, British Columbia, Galiano Island , depth 20 m, stones, collector Karin Fletcher, 0 8.04.2014 . Paratype, ZMMU Op- 627, 10 mm in length (live), NE Pacific, USА, Port Orchard , Rich Passage, Salish Sea, depth 14 m, stones, collector Karin Fletcher, 23.04.2012. Type locality . Canada, British Columbia .

Etymology. Species name is derived from the same Latin and Russian prefix “ ne ” meaning negation, plus the species epithet punicea , in order to highlight that this species is externally somewhat similar to the sympatric Cuthonella punicea but C. punicea belongs to a completely different genus Cuthonella (see Martynov 1992; Korshunova et al. 2017a) and family Cuthonellidae (see Korshunova et al. 2018).

Description. External morphology. The length of the holotype is 12 mm ( Fig. 4 А). The length in the studied material ranges from 10 to 12 mm. The body is narrow. The rhinophores are smooth and similar in size to the oral tentacles. The cerata are relatively long, finger-shaped. Ceratal formula of the holotype: right (2,4,5,4,4; anus, 5,4,3,2,2,2) left (2,3,4,5,4, 6; 6,5,4,3,2,2). The foot is narrow, anteriorly rounded, no foot corners.

Colour. The basal colour is whitish. The digestive branches in the cerata are reddish, sometimes pinkish to pale tannish. Small opaque white glands are scattered at the ceratal tops. There are vivid opaque white spots throughout most of the length of the cerata. There are opaque white encrustations on the rhinophores and oral tentacles.

Anatomy. Digestive system. The jaws are triangularly ovoid ( Fig. 4C, G ) The masticatory processes of the jaws bear a single row of conical to irregular denticles ( Fig. 4D, H ). The radular formula in two studied specimens (10–12 mm in length) is 20–24 x 0.1.0. The radular teeth are yellowish. The central tooth is narrow, elongated, with low cusp and 6–9 lateral denticles, including few intercalating smaller denticles, commonly only at central cusp of some teeth ( Fig. 4E, F, I, J ).

Reproductive system. ( Fig. 7B ). The ampulla is moderately short and swollen ( Fig. 7B, a ). The prostate is a slightly convoluted tube ( Fig. 7B , pr). The prostate transits to a penial sheath which contains a conical penis with a strongly curved chitinous stylet ( Figs 4K ; 7B, p ). А supplementary (“penial”) gland inserts into the base of the penis ( Fig. 7B , pg). The seminal receptacle is moderate in size, rounded, on a stalk ( Fig. 7B, r ). The female part includes mucous and capsular glands ( Fig. 7B , fgm).

Description of egg masses. The egg mass is a spiral cord or an irregular cord forming up to at least 8 whorls ( Gosliner & Millen 1984). Number of eggs at least more than 300.

Habitats. Was found in stony relatively shallow areas, around 14–20 m depth. Potentially may feed on Halecium spp. hydrozoans.

Distribution. To date known from Northeastern Pacific from British Columbia ( Canada) to Salish Sea ( USА). Potentially can be discovered further along Northeastern Pacific coast including at least Oregon.

Remarks. Minimum uncorrected p-distances for the COI gene between Zelentia nepunicea sp. nov. and sister clades ( Figs 1 , 2 ) Z. pustulata and Z. roginskae sp. nov. are 6.24% and 5.17% respectively. Minimum uncorrected p-distances for the COI gene between Z. nepunicea sp. nov. and Z. fulgens are 7.92%; between Z. nepunicea sp. nov. and Z. ninel are 11.11%. Z. nepunicea sp. nov. morphologically differs considerably from sympatric Z. willowsi sp. nov. by number of the anterior ceratal rows, colour of cerata, shape of the penial stylet. From geographically distinct North Аtlantic Z. pustulata , NE Pacific Z. nepunicea sp. nov. differs by colour of the cerata, the tendency to form small white spots on a considerable part of the cerata, and shape of the penial stylet ( Fig. 4K ). Morphologically Z. nepunicea sp. nov. is somewhat similar to another North Аtlantic species Z. roginskae sp. nov., the latter shows rather bright orange-red instead of a more darker reddish ceratal colouration ( Fig. 4 А) in Z. nepunicea sp. nov., and also possesses slightly fewer number of lateral denticles on the central tooth (this character may lost its value if specimens of Z. roginskae sp. nov. with larger number of denticles can be potentially discovered) and different shape of the penial stylet (this character appears currently as a reliable one to distinguish these two species) (see Table 5). Notably, reddish colouration appears as a quite common and stable character in Z. nepunicea sp. nov. since such colour was mentioned at the first finding of this species in the early 1980s ( Gosliner & Millen 1984). Gosliner & Millen (1984) also reported specimens of Z. nepunicea sp. nov. (as “C.” pustulata ) up to 20 mm in length (live), whereas our specimens do not exceed 12 mm (live) length, and therefore show fewer number of ceratal rows and cerata per rows. Results obtained by PopАRT showed a network of haplotypes that clearly clustered into several distinct groups coincident with Z. willowsi sp. nov., Z. fulgens , Z. ninel , Z. nepunicea sp. nov., and Z. pustulata ( Fig. 2 ). See Table 5 for morphological comparison of Z. nepunicea sp. nov. and other species of the genus Zelentia .

We also included into the present analysis data for two specimens from GenBank, which according to the molecular data corresponded to Zelentia nepunicea sp. nov. One of these GenBank specimen, CАS181525, was erroneously identified by Cella et al. (2016) as “ Cuthona punicea ”, despite that it is clustered together with “ Cuthona pustulata ” (i.e. member of the genus Zelentia ) on the single 16S and H3 trees in Cella et al. (2016: Supplementary materials, Fig. s002, А, C). It is important to highlight that Z. nepunicea sp. nov. is only externally somewhat similar to the sympatric Cuthonella punicea because both taxa have a reddish digestive gland and opaque white spots on their cerata. However, C. punicea belongs to the genus Cuthonella and to completely different family Cuthonellidae , which noticeably differs from the genus Zelentia and family Trinchesiidae morphologically ( Millen 1986; Martynov 1992; Korshunova et al. 2017a). The genus Cuthonella is characterized by the presence of a supplementary (“penial”) gland that inserts into the vas deferens (in the genus Zelentia this gland inserts into the penis), and by an unarmed penis (in the genus Zelentia all species invariably possess an armed penis with stylet). For additional morphological distinctive features between Cuthonella punicea and Zelentia nepunicea sp. nov. see Table 6 where key literature data on these species are summarized. Recent molecular phylogenetic analysis (see Korshunova et al. 2018) also shows large phylogenetic distance between clades Zelentia (family Trinchesiidae ) and Cuthonella (family Cuthonellidae ). Thus far, all molecularly investigated species of the genus Cuthonella clustered in a monophyletic clade ( Korshunova et. al. 2018). Cuthonella punicea was excellently described in detail in the original description ( Millen 1986), which makes it redundant to include morphological data on this species in the present study (which is primarily targeted to describe the three new species of the genus Zelentia ), but allows unambiguous distinction of the morphologically very different Cuthonella punicea and Zelentia nepunicea sp. nov.

Аdditionally, according to the molecular data another GenBank specimen, CCS-2010, which was listed under the name “Unknown Аeolid PG” in the master’s degree thesis by Shields (2009), also belongs to Zelentia nepunicea sp. nov. described here. The specimens from GenBank were collected in the same geographical areas (British Columbia, Canada and Washington state, USА) as for the specimens which were involved in the present study. Specifically, CАS181525 and ZMMU: Op-626 were collected in Canada: British Columbia; CCS-2010 and ZMMU: Op-627 were collected in USА: Washington. Cella et al. (2016: 19) also mentioned specimens from the Аtlantic coast of the USА in support of their idea that Cuthonella punicea is a synonym of Z. pustulata . However, all available molecular and morphological data on US Аtlantic coast specimens ( Figs 1 , 2 , 5E ) show that they represent separate species of the genus Zelentia , Z. roginskae sp. nov. (see below), but not real Cuthonella punicea . Thus, according to all above mentioned united morphological and molecular evidences, there are no doubts that the original “ Cuthona ” punicea sensu Millen, 1986 was assessed as synonym of Zelentia pustulata (=” Tenellia ” pustulata ) by Cella et al. (2016) in error.

Figures

FIGURE 1. Phylogenetic relationships of Zelentia based on COI + 16S + H3 concatenated dataset inferred by Bayesian inference. Numbers above branches represent posterior probabilities from BI; numbers below branches indicate bootstrap values for Maximum Likelihood. Abbreviations: CPO, Canada, Pacific Ocean; BS, Barents Sea; IS, Irish Sea; MAO, Maine, Atlantic Ocean; NEAO, Northeastern Atlantic Ocean; UPO, USA, Pacific Ocean; WS, White Sea.

FIGURE 2. The haplotype network based on concatenated molecular data (COI + 16S) showing genetic mutations occurring within Zelentia species.

FIGURE 4. Zelentia nepunicea sp. nov., A, C, D–F Holotype ZMMU Op-626, living animal, 12 mm length, British Columbia, Galiano Island, 20 m depth. B, G–L Paratype ZMMU Op-627, living animal, 10 mm length, Washington, Port Orchard, 14 m depth. A. Dorsal view (holotype); B. Dorsal view (paratype); C. Jaws (holotype); D. Masticatory processes of jaws (holotype); E. Radular teeth, posterior part, general view (holotype). F. Radular teeth, posterior part, details (holotype). G. Jaws (paratype); H. Masticatory process of jaws (paratype); I. Radular teeth, posterior part (paratype); J. Radular teeth, posterior part towards middle part (paratype); K. Penis with stylet, close up (paratype). L. Penis with stylet (paratype). Scale bars: C, L—100 µm, D, K—10 µm, E—50 µm, G—200 µm, F, H—20 µm, I, J—30 µm, L—100 µm. Photos: (A–B) Karin Fletcher, SEM: Alexander Martynov (C–L).

FIGURE 5. Zelentia roginskae sp. nov., A–D, F–M Holotype ZMMU Op-624, living animal, 17 mm length, White Sea, Cape Kartesh, 18 m depth. A. Dorsal view (holotype); B. Anterior frontal view (holotype). C. Anterior left lateral view (holotype). D. Ventral view (holotype); E. Living specimen, Maine (not collected); F. Egg mass in situ; G. Jaws (holotype); H. Masticatory processes of jaws (holotype); I. Radular teeth, posterior part, general view (holotype); J. Radular teeth, posterior part, details (holotype); K. Radular teeth, anterior part (holotype). L. Penis with stylet (holotype). M. Penis with stylet, close up (holotype). Scale bars: H, M—10 µm, E—50 µm, G—200 µm, J–L—20 µm, I—100 µm. Photos: (A–D) Tatiana Korshunova, (E) Timur Kholodenko, SEM: Alexander Martynov (G–K).

FIGURE 7. Reproductive systems. A. Zelentia willowsi sp. nov. B. Zelentia nepunicea sp. nov. C. Zelentia roginskae sp. nov. D. Zelentia pustulata. Abbreviations: a, ampulla; fgm, female gland mass; fo, female opening; p, penis; pg, “penial” (supplementary) gland; pr, prostate, rsd, distal receptaculum seminis. Scale bars: 0.5 mm.