Parallopharynx spp. (Trematoda: Digenea: Plagiorchioidea) in Iguanian Lizards from the Ærea de ConservaciÃ3n Guanacaste, Guanacaste, Costa Rica, including Parallopharynx matternae n. sp. in Basiliscus basiliscus (Squamata: Iguania: Corytophanidae)

We report 3 species of the digenean genus Parallopharynx, 1 previously undescribed, from the Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Parallopharynx gonzalezi, which was originally described in Basiliscus sp. and Ctenosaura similis from central Costa Rica, inhabits C. quinquecarinata; P. jonesi, originally described in Anolis lionotus (syn. Norops oxylophus) from Nicaragua, inhabits N. oxylophus, N. biporcatus, and Basiliscus basiliscus; and the new species, which inhabits B. basiliscus. Parallopharynx matternae n. sp. differs from all other members of the genus by having a metraterm extending posteriad from the genital pore to the posterior margin of the ventral sucker, whereas in P. arctus and P. gonzalezi, the metraterm never surpasses the midlevel of the ventral sucker and in P. jonesi it never passes the anterior margin of the ventral sucker, and by having an oral sucker that does not exceed 150 p.m in diameter with a subsequent greater oral-ventral sucker width ratio ranging from 1:0.88-1.12 (averaging 1:1), whereas values range from 1:0.71-0.83 for P. gonzalezi and P. arctus, and from 1:0.59-0.68 for P. jonesi. Parallopharynx spp. possesses Y-shaped excretory vesicles with a long central stem and short arms bifurcating immediately posterior to the ovary; similar to those found in members of the Telorchiidae. Additional similarities in the relative positions of the gonads and the structure of the cirrus sac and metraterm indicate a close relationship between Parallopharynx and members of the Telorchiidae. Caballero (1946) proposed Parallopharynx for P. arctus Caballero, 1946 on the basis of a single specimen inhabiting the intestine of the corytophanid lizard Basiliscus vittatus Wiegmann, 1828 from Guatemala. Neiland (1961) reported an additional specimen in an unidentified iguanid from Nicaragua, stating "though generally somewhat larger, agrees in all essential features with Caballero's Guatemalan type specimen". Two additional species have been described: Parallopharynx gonzalezi Brenes, Arroyo, and Montero-Gei, 1960 in the corytophanid lizard Basiliscus sp., and the iguanid lizard Ctenosaura s. similis Gray, 1831 from Rio Grande, Atenas, Provincia de Alajuela, Costa Rica, on the basis of "numerous" specimens (Brenes et al., 1960); and Parallopharynx jonesi Ubelaker, 1965 in the cloaca of the polychrotid lizard Anolis lionotus Taylor 1956 (= Norops oxylophus Guyer and Savage, 1986) from Nicaragua, on the basis of 20 specimens (Ubelaker, 1965). Thatcher (1963) redescribed P. arctus from specimens obtained from B. vittatus from Tabasco, Mexico, emending the generic diagnosis to include the presence of oral lappets, a muscular prepharynx, a spinose tegument, and a Y-shaped excretory vesicle. In this contribution from the activities of the inventory of eukaryotic parasites of vertebrates of the Area de Conservaci6n Guanacaste (ACG) in northwestern Costa Rica, we report P. gonzalezi, P. jonesi, and a previously undescribed species of