Dermatobranchus diagonalis Gosliner & Fahey, 2011

Description

Body elongate, flattened, narrowing posteriorly. The dorsum bears a series of about 30 shallow ridges set diagonal to the mantle edge, giving the dorsum a distinct leaf-like appearance; many ridges bifurcate along their length. The oral veil extends forward with rounded corners. Narrow, widely spaced rhinophores sit behind the oral veil and are almost cylindrical rather than bulbous, with longitudinal lamellae on the rounded club; the stalk does not narrow noticeably.
Ground colour of the dorsum, oral veil and foot is brown, much darker along the medial portion of the notum, with opaque white speckles and spots scattered randomly. A pale yellow band runs along the notum margin. Rhinophore stalks are white basally with brown clubs bearing opaque white lamellae and a touch of orange just below the opaque white apex. The oral veil is opaque white with a pale orange band along the anterior margin, and the dorsal surface of the foot margin is densely covered with reddish-brown speckling.

Distribution

Known only from Papua New Guinea and the Kerama Islands of Japan. Type locality: Rempi Lagoon, 25 km north of Madang, Papua New Guinea, 25 m.

Etymology

Verbatim from the original description (Gosliner & Fahey, 2011, p.302):

The specific name diagonalis refers to the numerous diagonal ridges found on the surface of the notum and is a Latinized noun in apposition.

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References

• カキシブオトメウミウシ（仮称）, 小野篤司. (1999). ウミウシガイドブック. TBSブリタニカ.
• Dermatobranchus sp. 3, Gosliner T.M., Behrens D.W. & Valdés Á. (2008). Indo-Pacific Nudibranchs and Sea Slugs: A field guide to the world's most diverse fauna. Sea Challengers Natural History Books, 426 pp.
• Dermatobranchus diagonalis sp. nov., GOSLINER T.M. & FAHEY S.J. (2011). Previously undocumented diversity and abundance of cryptic species: a phylogenetic analysis of Indo-Pacific Arminidae Rafinesque, 1814 (Mollusca: Nudibranchia) with descriptions of 20 new species of Dermatobranchus. Zoological Journal of the Linnean Society. 161(2): 245-356. https://doi.org/10.1111/j.1096-3642.2010.00649.x