The genus Halgerda was classified within the family Halgerdidae by Odhner (1934).[2]
Halgerdidae Odhner, 1926, is treated as a synonym of Discodorididae in the taxonomy of Bouchet & Rocroi (2005).[3] See also Valdés (2002).[4]
Seven species of Halgerda were described in the years 1880-1905, two species in 1932-1949, four species from 1975-1982, then 22 species in the years 1993-2001. In 2018 another six new species were described from Mozambique, highlighting the number of undescribed species on the African coast of the Indian Ocean.[5] A number of undescribed species are known and many species show considerable variation across their ranges, which may indicate that more cryptic species exist.[6]
Distribution
Species of Halgerda are confined to the Indo-West Pacific Tropical region apart from two species which are found in warm temperate waters of South Africa and Southern Australia and one species from warm temperate Japanese waters.
^Bergh, L.S.R. 1880. Beiträge zur Kenntniss der japanischen Nudibranchien. I. Verhandlungen der königlich-kaiserlich Zoologisch-botanischen Gesellschaft in Wien (Abhandlungen) 30:155-200, pls. 1-5, pages 191-5.
^Odhner N. H. (1934). "The Nudibranchiata, British Antarctic ("Terra Nova") Expedition, 1910". Natural History Report, Zoology7(5): 229-310.
^Tibiriçá, Y.; Pola, M.; Cervera, J. L. (2018). Systematics of the genus Halgerda Bergh, 1880 (Heterobranchia : Nudibranchia) of Mozambique with descriptions of six new species. Invertebrate Systematics.
^Gosliner, T.M., Behrens,D.W. & Valdes,A., 2008. Indo-Pacific Nudibranchs and Sea Slugs. A field guide to the World's most diverse fauna. Sea Challengers Natural History Books & The California Academy of Sciences. ISBN978-0-9700574-3-3
^MolluscaBase eds. (2023). MolluscaBase. Halgerda Bergh, 1880. Accessed through: World Register of Marine Species on 2023-06-18.