(syn. Caligulus Heegaard, 1962;Cresseyella Bezdek & Cressey, 2004; Midias Wilson C.B., 1911; Pargulus Shen, 1940; Pseudocaligus Scott A., 1901; Risculus Leach, 1819; Sciaenophilus Beneden, 1852; Scienophilus Beneden, 1852 (misspelling);Sinocaligus Shen, 1957.

"The genus Caligus, established by O.F. Müller in 1785, is the most speciose genus within the family of sea lice, the Caligidae. It currently comprises more than 250 species reported throughout the oceans and seas of the world and these species utilize a very broad range of fishes as hosts, although the great majority occur on teleosts (Margolis et al. 1975). In recent years several species have emerged as serious pests of finfish in commercial aquaculture facilities (Johnson et al. 2004). The complex of Caligus species referred to as the productus-group by Boxshall & Gurney (1980) is characterised by the loss of two and the reduction or loss of the third of the three plumose setae normally carried on the posterior margin of the distal exopodal segment of the first leg" From: Boxshall & El-Rshidi, 2004 .