New morphological and molecular data for (Gorgoderidae, Gorgoderinae) from (Tetraodontiformes, Tetraodontidae) in Mexican waters.

Adults of trematodes in the genus Linton, 1910 (Gorgoderidae, Gorgoderinae) are parasites found exclusively in the urinary bladders of tetraodontiform fishes. However, limited and unclear morphological data were used to describe the type species, Linton, 1910. Here, we present the first detailed morphological information for a member of . Morphological characters were described using light and scanning electron microscopy (SEM) of specimens from (Linnaeus) (Tetraodontiformes, Tetraodontidae), collected at six localities off the northern Yucatan Peninsula coast of the Gulf of Mexico. We also compared sequence fragments of the 28S (region D1-D3) ribosomal DNA and mitochondrial Cytochrome c oxidase subunit 1 (COI) gene with those available for other gorgoderine taxa. We assigned these specimens to , despite the incompleteness of published descriptions. The data provide a foundation for future work to validate the identities of , Linton, 1910 and (Travassos, 1920) with new collections from the type localities and hosts. Comparisons of 28S and COI regions described here also provide an opportunity to evaluate the monophyletic status of .