Halgerda punctata Farran, 1902

Description

A medium-sized Halgerda about 30 mm long. Body whitish with a pinkish tinge on the tips of some tubercles. The mantle is glabrous, lacking the villous covering of Halgerda formosa, and bears numerous large blunt tubercles arranged in diagonal lines connected by ridges that form an irregular triangular network across the dorsum. The mantle is sprinkled with rounded black spots (0.5-1.5 mm in diameter) of a tougher consistency than the surrounding integument; similar but often more numerous black spots occur on the ventral surface. Rhinophores are stout with black lamellate tips and thick white bases. Four tri-pinnate gills are white with black-shaded rachides; the anus is tubular and white with a black crenulate margin.

Distribution

Type locality: West of Donnan's Paar, Gulf of Manaar (off Sri Lanka), at 29 fathoms. Recorded from the Indian Ocean.

Etymology

The specific epithet punctata is the Latin for "dotted", from punctum meaning "point", in reference to the diagnostic black spots scattered across the dorsum and ventrum.

Remarks

Distinguished from congeners such as Halgerda formosa by the connected tubercular ridges and the symmetrical pattern of large rounded black spots.

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References

• Halgerda punctata, Farran G.P. (1905). Report on the Opisthobranchiate Mollusca collected by Professor Herdman, at Ceylon, in 1902. In: Herdman W.A. (ed.) Report to the Government of Ceylon on the pearl oyster fisheries of the Gulf of Manaar, with supplementary reports upon the marine biology of Ceylon. Royal Society, London. Part III, Suppl. 21: 329-364, pls. I-VI.
• Halgerda punctata, Terrence Gosliner, Ángel Valdés and David Behrens. (2018). Nudibranch and Sea Slug Identification Indo-Pacific 2nd Edition. New World Pubns Inc.