Phyllidiella zeylanica (Kelaart, 1858)

Description

An elongate-oval phyllidiid reaching up to 60 mm. Body covered by a tuberculate salmon-coloured mantle traversed by three continuous black lines that converge at the anterior and posterior tips of the dorsum: a broader inner line that encloses the rhinophore openings and the anal aperture, flanked by two narrower parallel lines (the outermost the narrowest). The dorsum carries pink compound tubercles aligned along the longitudinal ridges; tubercles also surround the anal opening, which sits on a black tubular projection. Rhinophores large, conical, pointed, the upper half black and circularly laminate; oral tentacles small and black. Foot whitish, anteriorly notched, with the dark viscera showing through; the rhinophore-sheath lamellae number 20–23 in animals over 30 mm.

Distribution

Tropical Indian Ocean from East Africa to Java, including the Red Sea, with records extending into the western Pacific. The type locality is Trincomalee, Ceylon (Sri Lanka).

Etymology

The specific epithet zeylanica derives from "Zeylon" / "Ceylon", the historical name for Sri Lanka — the type locality.

Remarks

Originally described as Phyllidia zeylanicus Kelaart (Journal of the Ceylon Branch of the Royal Asiatic Society 3(9): 108-109, 1858), where the author noted the species as "very rare". Subsequently transferred to Phyllidiella Bergh, 1869 (Brunckhorst 1993). Distinguished from the related Phyllidiella pustulosa by the distinct longitudinal arrangement of the pink tubercles along the dorsal ridges.

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References

• Phyllidia zeylanicus, Kelaart E.F. (1858). Description of new and little-known species of Ceylon nudibranchiate molluscs and zoophytes. Journal of the Ceylon Branch of the Royal Asiatic Society. 3(9): 84-139.
• Phyllidiella zeylanica, Brunckhorst D.J. (1993). The systematics and phylogeny of phyllidiid nudibranchs (Doridoidea). Records of the Australian Museum, Supplement 16: 1-107.
• Phyllidiella zeylanica, Terrence Gosliner, Ángel Valdés and David Behrens. (2015). Nudibranch and Sea Slug Identification Indo-Pacific. New World Pubns Inc.