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Scholz, T., Aguirre-Macedo, M. L. & Salgado-Maldonado, G., 2001, Trematodes of the family Heterophyidae (Digenea) in Mexico: a review of species and new host and geographical records, Journal of Natural History 35 (12), pp. 1733-1772 : 1753

Site of infection.? Gill arches (see Comments).

Distribution. YucataÂn (Chaamac).

References from Mexico. Scholz et al. (1997a).

Adult

Morphology. Scholz et al. (1997a: 175 ±176; ®gure 6A±F) redescribed this species on the basis of experimentally recovered adults. It is characterized mainly by the following features: a spindle-shaped body; a feebly developed anterior lobe; long, conical posterior appendage overlapping the pharynx; 18 massive, large (length 24±33) circumoral spines arranged in one complete row; the intestinal caeca reaching to the ovarian level.

De W nitive host. Chick (experimental).

Site of infection. Intestine.

Distribution. Not known (? YucataÂn).

References from Mexico. Scholz et al. (1997a).

Specimens deposited. IPCAS D-350.

Comments. Stein (1968) fed chicks upon viscera (liver and spleen) of the poeciliid Mollienisia latipinna (5 Poecilia latipinna ) from Florida and found adults of A. ( P.) macrostoma . However, no description or illustrations were provided and the morphology of metacercariae is still unknown. Observations of Stein (1968) cast doubts upon the site of infection of metacercariae A. ( P.) macrostoma from YucataÂn, supposed to be encysted in the gills ( Scholz et al., 1997a). It seems that they may have been encysted in the internal organs rather than directly in the gill ®laments.

Dronen (1985) reported adults of A. ( P.) macrostoma from the intestine of the roseate spoonbill ( Platalea ajaja ) from Texas that may be the principal de®nitive host. Trematodes found in the same host from Florida and identi®ed by SepuÂlveda et al. (1994) as Phagicola longa (USNPC 83030) may also be conspeci®c with A. ( P.) macrostoma (unpublished data) but they lack circumoral spines to con®rm species identi®cation.

Published data on the occurrence of A. ( P.) macrostoma suggest its distribution being limited to southeastern USA and Mexico ( Robinson, 1956; Stein, 1968; Dronen, 1985; Scholz et al., 1997a).