Trematodes of the family Heterophyidae (Digenea) in Mexico: a review of species and new host and geographical records Author Scholz, T. Author Aguirre-Macedo, M. L. Author Salgado-Maldonado, G. text Journal of Natural History 2001 2001-12-31 35 12 1733 1772 http://www.tandfonline.com/doi/abs/10.1080/00222930152667087 journal article 10.1080/00222930152667087 1464-5262 5275922 Ascocotyle ( Ascocotyle ) leighi Burton, 1956 Metacercaria Morphology . Sogandares-Bernal and Lumsden (1964) did not describe metacercariae found in Mexico . Second intermediate hosts . Belonesox belizanus Kner , Poecilia sphenops Valenciennes in Cuvier and Valenciennes ( Poeciliidae ). Site of infection . Heart. Distribution . YucataÂn (Progreso). References from Mexico . Sogandares-Bernal and Lumsden (1964) . Specimens deposited . None. Comments . Sogandares-Bernal and Lumsden (1964) found metacercariae of A. ( A. ) leighi in two poeciliid ®sh from Progreso, YucataÂn, most probably from CheleÂm lagoon. However, the authors did not provide any data on the morphology of metacercariae. Metacercariae of A. ( A. ) leighi are encysted exclusively in the heart and they have been found in poeciliid and cyprinodonti d ®sh in the USA and Mexico ( Burton, 1956 ; Sogandares-Bernal and Bridgman, 1960 ; Sogandares-Bernal and Lumsden, 1964 ). They diOEer from those of A. ( A. ) tenuicollis encysted in the heart as well mainly in the number of circumoral spines ( 48±52 in total, i.e. 24±26 in each row, in the former taxon versus 32, i.e. 161 16 in A. ( A. ) tenuicollis ) ( Burton, 1956 , 1958 ; Scholz et al ., 1997a ). Salgado-Maldonad o and Kennedy (1997) , and Salgado-Maldonad o et al . (1997) reported metacercariae of A. ( A. ) leighi from the gills, mesenteries, heart and kidney of several species of cichlids from southeastern Mexico . Although few reference specimens were preserved and available to the present authors, it is possible to assume that most, if not all, metacercariae previously reported as A. leighi were misidenti®ed and belonged to other species of the Ascocotyle- complex. Metacercariae from internal organs of cichlid, characid and poeciliid ®sh were conspeci®c with A . ( P ). nana and those encysted in the gills of cichlids with A. ( A. ) nunezae . Metacercariae encysted in the heart of ®sh of diOEerent families might belong to A. ( A. ) leighi but all voucher specimens examined were conspeci®c with A. ( A .) tenuicollis . Adult trematodes of A. ( A. ) leighi are not known from Mexico because specimens found in the intestine of Casmerodius albus from PaÂtzcuaro Lake (MichoacaÂn), identi®ed by G. PeÂrez Ponce de LeoÂn as A . leighi ( Lamothe-Argumedo et al. , 1997 ; CNHE 1532), belonged in fact to A . ( A .) tenuicollis (®gure 2).