Protomicrocotylidae

thumb|250 px|left|Clamps in various genera of Protomicrocotylidae: accessory sclerites (black) are present in Bilaterocotyloides and Protomicrocotyle, and absent in Neomicrocotyle. Clamps are absent in Lethacotyle. thumb|250 px|left|Ratio between clamp surface and body surface in eight families of gastrocotylinean monogeneans: the lowest ratio is in the protomicrocotylids thumb|250 px|left|Posterior part of a protomicrocotylid, showing bilateral asymmetry

Lethacotyle is a genus of polyopisthocotylean monogeneans, included in the family Protomicrocotylidae. The genus includes only two species: Lethacotyle fijiensis Manter & Price, 1953 , the type-species of the genus, and Lethacotyle vera Justine, Rahmouni, Gey, Schoelinck, & Hoberg, 2013 . Both species are parasitic on the gills of jacks in the Pacific Ocean. They are known only from three localities: off Fiji, Andaman Islands, and New Caledonia. The genus Lethacotyle is special in that its members have no clamps on their posterior attachment organ or haptor, in contrast to most polyopisthoco