Thuridilla multimarginata Gosliner, 1995

Description

Body length about 9 mm. Background colour light to dark green. The parapodia bear a sequence of several undulating bands or interrupted series of bands. The margin contains interrupted spots of opaque white, below which is a series of interrupted patches of bright orange. Ventral to this is a series of thin undulating bands of black, reflective blue, and black. The head and most of the rhinophores have opaque white pigment with a black tip.

Distribution

South Africa, windward and leeward Hawaiian Islands.

Etymology

The specific epithet multimarginata refers to the multiple bands of pigment along and below the parapodial margins.

Remarks

This species retains some of the least derived anatomical features in the genus. The buccal mass is highly muscularized with a proportionately small pharyngeal pouch. The radular teeth are broad with a prominent dorsal notch and bear striations that extend from the denticles onto the surface. The lateral pericardial vessels have been lost, and the posterior vessels share a common insertion with the pericardium. The duct of the receptaculum seminis is elongate.
Externally, Thuridilla multimarginata resembles Thuridilla indopacifica and Thuridilla livida; all three share orange, black and blue parapodial lines. Thuridilla multimarginata differs in having additional white pigment and an additional black-orange line absent in the others; both Thuridilla indopacifica and Thuridilla livida lack the plesiomorphic features described above.

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References

• Thuridilla multimarginata sp. nov., Gosliner T.M. (1995). The genus Thuridilla (Opisthobranchia: Elysiidae) from the tropical Indo-Pacific, with a revision of the phylogeny and systematics of the Elysiidae. Proceedings of the California Academy of Sciences. 49(1): 1-54.
• Thuridilla multimarginata, Terrence Gosliner, Ángel Valdés and David Behrens. (2018). Nudibranch and Sea Slug Identification Indo-Pacific 2nd Edition. New World Pubns Inc.