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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 (1994) as Phagicola longa (USNPC 83030) may also be conspeci®c with A. (P.) macrostoma (unpublished data) but they lack circumoral spines to con®rm species identi®cation.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).