Corresponding author: Alexander Martynov (
Academic editor: Nathalie Yonow
Morphological and molecular data are presented for the first time in an integrative way for the genus
Martynov A, Mehrotra R, Chavanich S, Nakano R, Kashio S, Lundin K, Picton B, Korshunova T (2019) The extraordinary genus
The genus
Three specimens of two new Japanese species were collected by SCUBA diving in the Pacific coast of Japan (Honshu, Osezaki) by Tatiana Korshunova, Alexander Martynov, and Hiroshi Takashige. Three specimens of
All specimens were examined with a stereomicroscope (MBS-9) and photographed using Nikon D-90 and D-810 digital cameras with a set of extension rings. The pharynxes were removed and processed with a weak solution of domestic bleach (NaClO). The jaws were examined using a stereomicroscope and digital cameras. The jaws and radulae were examined under a scanning electron microscope (JSM and CamScan Series II) (Figs
Specimens of
List of samples, localities, and voucher references. The species in bold font are those sequenced in this study.
Species | Voucher, Locality |
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16S |
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ZSM 20020700 Chile |
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MNCN:15.05/74477 France |
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MNCN:15.05/74483 Oregon, USA |
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ZMMU:Op-559 Russia |
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ZMMU Op-560 Norway |
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CASIZ174212 Line Islands |
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MNCN/ADN51933 France |
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ZMMU:Op-484 Russia |
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GNM9094 Scotland |
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ZMMU:Op-600 Sweden |
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ZMMU:Op-510 Russia |
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CASIZ184527 Japan |
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CASIZ176146 South Africa |
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ZMMU:Op-603 Norway |
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ZMMU:Op-545 Norway |
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MNCN/ADN51957 Spain |
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ZMMU:Op-521 Russia |
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ZSM:Mol:20110345 Brazil |
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– |
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ZSM Mol 20110338a Brazil |
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– |
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ZSM Mol 20110338b Brazil |
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– |
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ZSM Mol 20020957 France |
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– |
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ZSM Mol 20100125 Croatia |
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– |
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MNCN15.05/53691 Senegal |
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ZMMU:Op-522 Russia |
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ZMMU:Op-524 Russia |
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ZMMU:Op-537 Russia |
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ZMMU:Op-295 Russia |
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ZMMU:Op-286 Russia |
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ZMMU:Op-391 Russia |
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LACM2003-41.5 |
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ZMMU:Op-525 Norway |
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– |
CAS184184 New Hampshire |
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GNM |
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– | |
CASIZ186258 Philippines |
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MNCN15.05/53695 Spain |
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CASIZ178875 Costa Rica |
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CASIZ 186044 Philippines |
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CASIZ 088586 USA |
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ZMMU:Op-508 Norway |
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CASIZ176320 South Africa |
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NM:W7469 Indian |
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UMMZ302975 North Atlantic |
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CASIZ176985 Indian |
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CASIZ176985 Indian |
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CASIZ176385 South Africa |
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ZMMU:Op-408 Norway |
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CPIC01115 Canada |
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CPIC00565 USA, California |
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ZMMU:Op-532 Russia |
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ZSM Mol-20070592 Chile |
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MNCN15.05/53698 Spain |
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ZMMU:Op-503 Norway |
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ZMMU:Op-399 Russia |
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– |
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ZMMU:Op-498 Russia |
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CAS179466 California |
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CASIZ 177520 Philippines |
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CASIZ 177576 Philippines |
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MABIK MO0015762 Korea |
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CASIZ178876 USA, California |
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ZMMU:Op-530 Japan |
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CAS184191 New Hampshire |
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WS3463 Barents Sea |
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ZMMU:Op-622 Norway |
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CASIZ176219 South Africa |
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ZMMU:Op-572 Norway |
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ZMMU:Op-509 Russia |
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ZMMU:Op-557 Russia |
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The molecular analysis revealed and confirmed the position of the genus
Molecular phylogenetic analyses among other important results also revealed phylogenetic positions of the type taxon
One pair of anterior rows of cerata, posterior cerata in rows, few (1–3) peculiar club-shaped cerata per row, anus acleioproctic, rhinophores smooth, oral tentacles present, no anterior foot corners, cnidosacs present, pharynx moderately broad, jaws with wing-shaped anterior expansion, smooth masticatory edges, radula very small, uniserial, radular teeth very narrow, triangular with strong cusp, lateral denticles small, penis unarmed, supplementary glands absent.
All
1 specimen, ZMMU Op-667, 6 mm long (fixed), Thailand, Koh Samaesan, 21 June 2018, depth 8 –16 m, soft sediment habitats, hydroids, collectors Rahul Mehrotra, Suchana Chavanich. 2 specimens, ZMMU Op-668, ca. 3 and 2 mm (fixed) same locality and collectors.
Thailand, Chonburi, Koh Samaesan.
Up to eight ceratal rows, ground colour translucent greyish, ceratal cores light to dark greyish, ceratal tops dull reddish, apices with white spot, anterior cerata with prominent reddish basal spot (distributed over the whole surface in some cerata), white gonad spherules moderately dense, sparse white spots in the first half of the dorsal part, cerata moderately widened at top without smaller separate cupola-shaped tip, central tooth with sharp to pitted top and numerous lateral denticles, up to 23 small denticles, irregular in size, no distinct furrows and ridges on the teeth surfaces, no accessory penial gland, penis unarmed.
Body very elongate, up to 6 mm in preserved length (up to 10 mm alive) (Fig.
Reproductive system diaulic (Fig.
Comparison of
Subtidal, highly cryptic on
Presently found only at Koh Samaesan, Thailand, but expected to be found in neighbouring regions of the Indo-West Pacific.
Thai specimens show closeness to the type species of the genus
Holotype, ZMMU Op-610, ca. 12 mm long (alive), Japan, Osezaki, 10 Sept 2016, depth 7–15 m, stones, rocks, hydroids, collector Tatiana Korshunova, Alexander Martynov. Paratype, ZMMU Op-611, Japan, Uchiura, 09 Sept 2016 depth 20 m, collector Hiroshi Takashige.
Japan.
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.
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.
Body very elongate, holotype ca. 12 mm alive (Fig.
Reproductive system diaulic (Fig.
Subtidal, on stony and rocky area with the hydroids
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.
The type species of the genus
Reproductive systems of new species of the genus
Phylogenetic tree of aeolidacean nudibranchs based on concatenated molecular data (
Morphological comparison of the species belonging to the genus
Maximum length alive | Colour of central branches of digestive gland | Colour of digestive branches in cerata | Colour of internal spot of digestive gland in upper part of cerata | Colour of large spot of digestive glad at the base of right anterior cerata | Radula teeth | |
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10 mm | Greyish | Greyish | Reddish | Reddish | With sharp to pitted central cusp and numerous indistinct, irregularly placed lateral denticles (up to at least 23), no furrows and ribs |
12 mm | Brownish, few pieces greyish | Greyish to whitish | Pinkish-brownish | Brownish | With very sharp central cusp and up to ca. 20–30 of small irregular in size denticles, often hard to delineate, with deep furrows and fine rib-like structures | |
20 mm | Dark brownish | Whitish to light cream | Dark brownish | Dark brownish | With sharp, largely non-pitted cusp and up to ca. 10 (often no more than 5 denticles) relatively distinct small denticles in anterior part of radula to completely smooth or with very indistinct denticles in posterior part of radula | |
15 mm | Green | Green | Brown | “Brown-chocolate” | With sharp pointed central cusp and 6–10 distinct regularly placed lateral denticles |
Holotype, ZMMU Op-612, ca. 20 mm long alive, Japan, Osezaki, 10 Sept 2016, depth 7–15 m, stones, rocks, hydroids, collector Tatiana Korshunova, Alexander Martynov.
Japan, Osezaki.
After the Japanese name hyōtan (瓢箪, ヒョウタン) for the calabash
Up to eight ceratal rows, ground colour translucent greyish, ceratal cores white to dark greyish, ceratal tops dull reddish, no apical white spot, anterior cerata with prominent dark brownish basal spot, sparse white spots in the first half of the dorsal part, white gonad spherules very dense, cerata considerably widened at top with smaller separate cupola-shaped tip, central tooth narrowly triangular with largely non-pitted top and only few denticles, up to ten small denticles, irregular in size; no accessory penial gland, penis unarmed.
Body very elongate, holotype ca. 20 mm (alive, Fig.
Reproductive system diaulic (Fig.
Subtidal, on stony and rocky area with hydroids
Central parts of the Pacific coast of main Japanese island Honshu; potentially can occur at the southern parts of Honshu and Kyushu.
The type species of the genus
The phylogeny and taxonomy of the
Our present molecular data and morphological analysis of the genus
The long taxonomic problem of the classification of the aeolidacean nudibranch family
Originally, the type species of the genus
The photograph of
While
The family
The present study confirms that
For the taxonomy of the traditional family
Hiroshi Saito (National Museum of Nature and Science, Tsukuba) and Hiroshi Takashige (Tokyo) are warmly thanked for the help during our collecting trip in Japan in September 2016. We also give special thanks to the team of Gulen Dive Resort (Christian Skauge, Ørjan Sandnes, Monica Bakkeli, and Guido Schmitz) for their generous help during fieldwork in Norway, as these specimens were used for comparative purposes in this study. Electron Microscopy Laboratory MSU is thanked for support with electron microscopy. This study was supported by research project of MSU Zoological Museum (AAAA-A16-116021660077-3) and in frame of Moscow University Project “Noah’s Ark”. The authors also thank the Plant Genetic Conservation Project under the Royal Initiative of Her Royal Highness Princess Maha Chakri Sirindhorn and the Naval Special Warfare Command, Royal Thai Navy, and TASCMAR EU Horizon 2020 for their assistance during the sample collections in Thailand.