Onychodiaptomus is a genus of copepods in the family Diaptomidae, containing the following species: \n* Onychodiaptomus birgei (Marsh, 1894) \n* Onychodiaptomus hesperus M. S. Wilson & Light, 1951 \n* Onychodiaptomus louisianensis M. S. Wilson & W. G. Moore, 1953 \n* Onychodiaptomus sanguineus (S. A. Forbes, 1876) \n* Onychodiaptomus virginiensis (Marsh, 1915) Onychodiaptomus louisianensis, a species endemic to the United States, is listed as Data Deficient on the IUCN Red List.