Dendronotus pseudodalli Ekimova, Mikhlina, Stanovova, Krupitskaya, Chichvarkhina et Schepetov, 2023

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, Ruthenica, Russian Malacological Journal 34 (2), pp. 69-91 : 81-82

Dendronotus pseudodalli Ekimova, Mikhlina, Stanovova, Krupitskaya, Chichvarkhina et Schepetov, 2023

( Fig. 7C)

Material studied: MIMB44619 , 1 specimen, Sea of Okhotsk, Sakhalin Is., 52°12’4”N, 144°26’8”E, depth 192–218 m, 30 July 2019, coll. A. Mayorova. MIMB44620 , 1 specimen, Sea of Okhotsk , Sakhalin Is., 54°27’9”N, 142°14’3”E, depth 38 m, 31 July 2019, coll. A. Mayorova. MIMB44621 , 1 specimen, same locality and collection date .

Diagnosis: Body elongated, up to 27 mm in length, uniform milky-white to pale pink. Large oral veil with up to six simple secondary branched appendages, rhinophoral sheath with up to five branched appendages, lateral papilla present, five pairs of dorsolateral appendages with secondary and tertiary branching, tips with opaque white pigment. Jaws elongate with slightly curved masticatory border bearing single row of small blunt denticles. Radular formula 46 × 8–10.1.8–10. Triangular rachidian tooth with up to 11 large denticles on both sides. Lateral teeth with sharp elongated cusp and 2–5 small denticles. Ampulla S-shaped. Prostate with 18 alveolar glands, arranged in double ring. Penis curved.

Distribution: Known only from Sakhalin Island, from two localities: off northeastern Sakhalin coast (192–218 m depth) and from Severny Bay (38 m depth) [ Ekimova et al., 2023a].

Remarks: This species performs identical external morphology with sympatrically living D. dalli but is considerably different from this species in both internal morphology and on the molecular level [see Ekimova et al., 2023a for details].