Hemilamprops Sars, 1883: 11, 55.
Lampropoides.— Harada, 1959: 231, 237
Type species. Vaunthompsonia rosea Norman, 1863, by subsequent designation ( Lomakina 1958a).
Diagnosis. Carapace not dorsoventrally flattened, marginal carina absent, eyelobe present, pseudorostral lobes short, blunt. Antennule flagella variable, accessory flagellum at least 0.5 length of main flagellum. Mandible navicular. Maxillule palp with 2 setae. Pereopod 1 slender, basis shorter than all other articles together. Pereopod 5 longer than pereopod 4 basis. Telson long, at least 2/3 length of uropod peduncles. Uropod endopod of 3 articles. Uropod exopod article 1 at least 0.5 length of article 2. Female with fully developed exopod on pereopod 2, rudimentary exopods on pereopods 3–4, without pleopods. Male with long antenna, extending past pereon, without penial lobes, with 3 pairs of pleopods.
Species. Hemilamprops assimilis Sars, 1900, H. bacescui Petrescu & Wittmann, 2003, H. bicarinatus Ledoyer, 1988, H. bigibbus Gamô, 1975, H. californicus ( Zimmer 1936), H. chilensis ( Gerken & Haye, 2018), H. cristatus ( Sars, 1870), H. diversus Hale, 1946, H. emiensis Gamô, 1999, H. glabrus Day, 1978, H. gracilis Hart, 1930, H. impellucidus n. sp., H. izuanus Harada, 1959, H. japonicas ( Harada, 1959), H. latus Hale,1946, H. merlini Mühlenhardt-Siegel 2005, H. miyakei Gamô, 1967, H. normani Bonnier, 1896, H. pacificus ( Harada, 1959), H. pectinatus Lomakina, 1955, H. pellucidus Zimmer, 1908, H. pterini Shalla & Bishop, 2007, H. roseus ( Norman, 1863), H. serrulatus Ledoyer, 1977, H. tanseianus Gamô, 1967, H. ultimaspei Zimmer, 1921, H. uniplicatus ( Sars, 1872).
Remarks. Members of Hemilamprops can be difficult to impossible to distinguish from Lamprops and Alamprops if males are not present. There are some problematic species that have been placed in Hemilamprops: H. abyssi Gamô, 1989 and H. bicarinatus Ledoyer, 1988. Hemilamprops abyssi does not meet the definition of Hemilamprops given above, as the first article of the uropod exopod is 0.4 the length of article 2, rather than 0.5 or more the length of article 2, and is transferred to Pseudolamprops. The description of H. bicarinatus is based on two incomplete female specimens. The carapace sculpturing, which includes a marginal carina, suggests that Hemilamprops is not the correct genus, as does the reduced pereopod 5. However, without specimens that are more nearly complete, and perhaps the adult male, it is not possible to be definitive about the genus placement, so the species is retained in Hemilamprops for the present.