Margotrema guillerminae n. sp. (Trematoda: Macroderoididae) from two species of freshwater fishes in Lake Zacapu, Michoacan State, Mexico, and new records of Margotrema bravoae Lamothe, 1970.

Margotrema guillerminae n. sp. is described from the cyprinid Hybopsis calientis and the goodeid Alloophorus robustus from Lake Zacapu, Michoacán State, in the Mesa Central of Mexico. The new species is easily distinguished from the only other species of the genus, M. bravoae, by having short ceca, extending posteriad to reach the region of the anterior testis, vitelline follicles that are mainly lateral to the ceca but with some intercecal (particularly at the ovarian region), and a seminal receptacle that is located immediately posterior to the ovary. Previous records of Urorchiinae gen. sp. and Margotrema sp. from Alloophorus robustus from Lake Pátzcuaro refer to M. bravoae, which appears to be specific to members of the Goodeidae.