Genera in Plagiorhynchidae are divided into three subfamilies: Plagiorhynchinae, Porrorchinae, and Sphaerechinorhynchinae.[1][a]
P. cylindraceus was found infesting the Austral thrush (Turdus falcklandii) in central Chile.[4] Janice Moore[5] discovered P. cylindraceus to be a parasite that infects an intermediate host, the terrestrial isopod Armadillidium vulgare, which alters its behavior and becomes more susceptible to P. cylindraceus' primary host, the European starling (Sturnus vulgaris).
L. inscripta was found infesting the Austral thrush (Turdus falcklandii) in central Chile.[4] It has also been found in the Puerto Rican lizard Anolis cristatellus.[6]
S. macropisthospinus has been found in the intestine of the tiger (Panthera tigris) and a water monitor (Varanus salvator) in Vietnam.[7]