Cadlina umiushi Korshunova, Picton, Sanamyan et Martynov 2015
Creators: name: Ekimova, Irina A.
name: Grishina, Darya Yu.
name: Nikitenko, Ekaterina D.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Nudibranchia
Cadlinidae
Cadlina
Cadlina umiushi

description: Cadlina umiushi Korshunova, Picton, Sanamyan et Martynov, 2015
(Figs 1C–E, H, I, L, M, P; 2A)
Material studied: MIMB48043, 1 specimen, dissected, the Sea of Okhotsk, Aniva Bay, Moguchi River, Hirano ridge, 46°05.372’N, 142°13.612’E, 20 m in depth, 20.08.2013, coll. A. Plaksin,A. Semenov. MIMB48042, 1 specimen, dissected, same locality, date and collectors as MIMB48043.
Type locality: Sea of Japan, Peter the Great Bay, Bolshoy Pelis Is., 5–7 m depth.
Diagnosis: Length 13–24 mm (preserved specimens). Notum semitransparent white, rounded anteriorly, posteriorly, covered with numerous yellow rounded spots on dorsal side. Large yellow subepidermal glands on dorsolateral sides of notum. Well-defined yellow line around notal edge. Buccal bulb with labial cuticle, formed by bifid to trifid or rarely unicuspidal rodlets. Radular formula: 73 × 21–27.1.21–27. Rachidian tooth trapezoid, elongate, slightly narrowed apically, with 5–7 denticles, sometimes with bifurcations, inner denticles larger than outer denticles. Lateral teeth hook-shaped with up to 12 denticles. Reproductive system triaulic (Fig. 2A). Ampulla massive, convoluted, muscular. Penis armed with small, densely arranged hamate spines. Vas deferens long and winding, with long expanded prostatic part, narrowing near penis. Receptaculum seminis small, oval; bursa copulatrix large, rounded, muscular.
Molecular data: A BLAST-n search of COI sequence resulted 99.53% identical to 2 sequences of Cadlina umiushi (type specimens, MN224067 and MN224068) thus confirming the species identity of our samples.
Distribution: This species was originally described from the Sea of Japan, Peter the Great Bay and adjacent areas, e.g. Spokoinaya Bay, Rudnaya Bay [Martynov et al., 2015a,b; Korshunova et al., 2020a; Chichvarkhin, 2016]. It was discovered further south, in the Sea of Japan waters of South Korea [Do et al., 2020]. Our results extend the geographical range of this species to southern parts of the Sea of Okhotsk (Aniva Bay).
Remarks: Specimens from Aniva Bay show slight morphological differences from the type specimens of C. umiushi: the latter have mostly bifid and rarely trifid rodlets of the labial cuticle, and their rachidian teeth are trapezoid, bearing 5–6 denticles almost equal in size or slightly larger [Korshunova et al., 2020a]. In specimens from Aniva Bay the rodlets are commonly bifid and trifid, with rare unicuspid elements (Fig. 1H), the rachidian tooth is elongated trapezoid, commonly with 5–6 large denticles among which central denticles are the largest.
description: Published as part of Ekimova, Irina A., Grishina, Darya Yu. & Nikitenko, Ekaterina D., 2024, Nudibranch molluscs of Sakhalin Island, Northwestern Pacific: new records and descriptions of two new species, pp. 69-91 in Ruthenica, Russian Malacological Journal 34 (2) on pages 72-74, DOI: 10.35885/ruthenica.2024.34(2).3, http://zenodo.org/record/11042878