Halgerda toliara Fahey & Gosliner, 1999

Description

A translucent white nudibranch with a distinctive pattern of reticulate yellow ridges across the dorsum. The rhinophore clubs are black, and the gills are white with black tips. Small yellow pustules line the mantle margin. Body size ranges from 5 to 40 mm. Closely resembles Halgerda formosa but is distinguished by the absence of black spots on the mantle. Known as the Lightning Waffle Dorid.

Distribution

Found in the western Indian Ocean. The type locality is Toliara, southern Madagascar. Recorded from Madagascar (including Nosy Be), Mozambique, South Africa (Natal), and Mayotte. Inhabits coral reef environments at depths of 6 to 28 m.

Etymology

The specific epithet toliara refers to the city of Toliara in southern Madagascar, the type locality of this species.

Remarks

A member of the family Discodorididae. Like other members of the genus Halgerda, this species is presumed to feed on sponges. It was described by a 1999 revision as one of three new Halgerda species from the western Indian Ocean, in a paper that also redescribed H. formosa. The close external resemblance between H. toliara and H. formosa has been noted, and further data on intraspecific variation in both species are needed.

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References

• Halgerda toliara sp. nov., Fahey S.J. & Gosliner T.M. (1999). Description of three new species of Halgerda (Nudibranchia: Halgerdidae) from the western Indian Ocean with a redescription of Halgerda formosa Bergh, 1880. Proceedings of the California Academy of Sciences, (4) 51(8): 365-383.
• Halgerda toliara, Gosliner, T. et al. (2023). Southern African Sea Slugs. Southern Underwater Research Group Press, 7 Blackwood Drive, Hout Bay 7806, Cape Town, South Africa.