• Aartsenia arctica (Dall & Bartsch, 1909): ectoparasitic
• Aartsenia candida (Møller, 1842): ectoparasitic
• Aartsenia japonica (A. Adams, 1860): ectoparasitic
• Aartsenia martensi (Dall & Bartsch, 1906): ectoparasitic
• Aartsenia pupiformis (P. P. Carpenter, 1865): ectoparasitic
• Aartsenia sagamiensis Kuroda & T. Habe, 1971: ectoparasitic
• Aartsenia sasagensis (Nomura, 1939) †: ectoparasitic
• Aartsenia sikisimana (Nomura, 1939) †: ectoparasitic
• Abasia inflata Cressey & Cressey, 1979: ectoparasitic
• Abasia pillaii Cressey & Cressey, 1979: ectoparasitic
• Abasia platyrostris Pillai, 1963: ectoparasitic
• Abasia pseudorostris Wilson C.B., 1908: ectoparasitic
• Abasia pusilla Cressey & Cressey, 1979: ectoparasitic
• Abasia tripartita (Shiino, 1955): ectoparasitic
• Abergasilus amplexus Hewitt, 1978: ectoparasitic
• Abortipedia indica Unnithan, 1962: ectoparasitic
• Abscondicola humesi Fiers, 1990: ectoparasitic
• Absonifibula bychowskyi Lawler & Overstreet, 1976: ectoparasitic
• Absonifibula estuarina Santos & Timi, 2009: ectoparasitic
• Abyssoaclis alagoensis J. Barros, Mello, F. Barros, S. Lima, Santos, Cabral & Padovan, 2003: ectoparasitic
• Abyssopontius altus Stock, 1985: ectoparasitic
• Acaenomolgus gottoi Stock, 1995: ectoparasitic
• Acaenomolgus protulae (Stock, 1959): ectoparasitic
• Acaenomolgus serpulae (Stock, 1960): ectoparasitic
• Acanthobdella livanowi (Epshtein, 1966): ectoparasitic
• Acanthobdella peledina Grube, 1851: ectoparasitic
• Acanthocanthopsis chilomycteri (Thomson, 1889): ectoparasitic
• Acanthocanthopsis quadrata Heegaard, 1945: ectoparasitic
• Acanthocercodes bullardi Kritsky & Diggles, 2015: ectoparasitic
• Acanthocercodes polynemus (Tripathi, 1957) Kritsky & Diggles, 2015: ectoparasitic
• Acanthocercodes spinosus (Maillard & Vala, 1980) Kritsky & Diggles, 2015: ectoparasitic
• Acanthochondria alatalongicollis Heegaard, 1940: ectoparasitic
• Acanthochondria alleni Tang, Kalman & Ho, 2010: ectoparasitic
• Acanthochondria bicornis Shiino, 1955: ectoparasitic
• Acanthochondria brevicorpa Yü, 1935: ectoparasitic
• Acanthochondria clavata (Bassett-Smith, 1896): ectoparasitic
• Acanthochondria constricta Shiino, 1955: ectoparasitic
• Acanthochondria cornuta (Müller O.F., 1776): ectoparasitic
• Acanthochondria cyclopsetta Pearse, 1952: ectoparasitic
• Acanthochondria diastema Kabata, 1965: ectoparasitic
• Acanthochondria dilatata Shiino, 1955: ectoparasitic
• Acanthochondria dojirii Kabata, 1984: ectoparasitic
• Acanthochondria elongata (Bassett-Smith, 1898): ectoparasitic
• Acanthochondria epachthes (Wilson C.B., 1908): ectoparasitic
• Acanthochondria eptratreti Cheng, Luo, Dai & Shih, 2014: ectoparasitic
• Acanthochondria exilipes Wilson C.B., 1932: ectoparasitic
• Acanthochondria fissicauda Shiino, 1955: ectoparasitic
• Acanthochondria fraseri Ho, 1972: ectoparasitic
• Acanthochondria galerita (Rathbun, 1886): ectoparasitic
• Acanthochondria glandiceps Shiino, 1955: ectoparasitic
• Acanthochondria helicoleni Cantatore & Timi, 2010: ectoparasitic
• Acanthochondria hippoglossi Kabata, 1987: ectoparasitic
• Acanthochondria hoi Kalman, 2003: ectoparasitic
• Acanthochondria incisa Shiino, 1955: ectoparasitic
• Acanthochondria inimici Yamaguti, 1939: ectoparasitic
• Acanthochondria kajika Ho & Kim I.H., 1996: ectoparasitic
• Acanthochondria krishnai Aneesh, Helna & Kumar, 2020: ectoparasitic
• Acanthochondria laemonemae Capart, 1959: ectoparasitic
• Acanthochondria lepidionis Barnard, 1955: ectoparasitic
• Acanthochondria lilianae Cantatore, Lanfranchi & Timi, 2011: ectoparasitic
• Acanthochondria limandae (Krøyer, 1863): ectoparasitic
• Acanthochondria longifrons Shiino, 1955: ectoparasitic
• Acanthochondria macrocephala Gusev, 1951: ectoparasitic
• Acanthochondria margolisi Kabata, 1984: ectoparasitic
• Acanthochondria ophidii (Krøyer, 1863): ectoparasitic
• Acanthochondria oralis Yamaguti, 1939: ectoparasitic
• Acanthochondria phycidis (Rathbun, 1886): ectoparasitic
• Acanthochondria pingi (Yü & Wu, 1932): ectoparasitic
• Acanthochondria platycephali Heegaard, 1940: ectoparasitic
• Acanthochondria priacanthi Shiino, 1964: ectoparasitic
• Acanthochondria rectangularis (Fraser, 1920): ectoparasitic
• Acanthochondria sagitta Alarcos & Timi, 2011: ectoparasitic
• Acanthochondria serrani Braicovich & Timi, 2009: ectoparasitic
• Acanthochondria shawi Yü, 1935: ectoparasitic
• Acanthochondria sicyasis (Krøyer, 1863): ectoparasitic
• Acanthochondria sixteni (Wilson C.B., 1922): ectoparasitic
• Acanthochondria soleae (Krøyer, 1838): ectoparasitic
• Acanthochondria spirigera Shiino, 1955: ectoparasitic
• Acanthochondria tasmaniae Heegaard, 1962: ectoparasitic
• Acanthochondria tchangi Yü, 1935: ectoparasitic
• Acanthochondria triangularis Alves, Luque & Paraguassu, 2003: ectoparasitic
• Acanthochondria triglae Herrera-Cubilla & Raibaut, 1990: ectoparasitic
• Acanthochondria uranoscopi Ho & Kim I.H., 1995: ectoparasitic
• Acanthochondria vancouverensis Kabata, 1984: ectoparasitic
• Acanthochondria yui Shiino, 1964: ectoparasitic
• Acanthochondrites annulatus (Olsson, 1869): ectoparasitic
• Acanthocolax exilipes (Wilson C.B., 1911): ectoparasitic
• Acanthocolax hystricosus Cressey, 1983: ectoparasitic
• Acanthocolax peruensis (Luque & Bruno, 1990): ectoparasitic
• Acanthocolax similis Vervoort, 1969: ectoparasitic
• Acanthocotyle atacamensis Ñacari, Sepúlveda, Escribano & Oliva, 2019: ectoparasitic
• Acanthocotyle elegans Monticelli, 1890: ectoparasitic
• Acanthocotyle greeni Macdonald & Llewellyn, 1980: ectoparasitic
• Acanthocotyle gurgesiella Ñacari, Sepulveda, Escribano & Oliva, 2017: ectoparasitic
• Acanthocotyle imo Ñacari, Sepúlveda, Escribano & Oliva, 2019: ectoparasitic
• Acanthocotyle lobianchi Monticelli, 1888: ectoparasitic
• Acanthocotyle pacifica Bonham & Guberlet, 1938: ectoparasitic
• Acanthocotyle patagonica Kuznetsova, 1975: ectoparasitic
• Acanthocotyle pugetensis Bonham & Guberlet, 1938: ectoparasitic
• Acanthocotyle urolophi Kearn, Whittington, Chisholm & Evans-Gowing, 2016: ectoparasitic