Morphological and Molecular Data Reveal Two New Species of Viannaia (Nematoda: Viannaiidae), Parasitizing Opossums (Mammalia: Didelphidae) in Mexico.

Two new species of Viannaia from the intestine of the North American opossums, Didelphis virginiana (Virginia opossum), and Philander opossum (gray four-eyed opossum), are described based on morphological and molecular data, through an integrative taxonomic approach. Maximum likelihood and Bayesian inference analyses for each dataset and the concatenated dataset were performed using a mitochondrial cytochrome c oxidase subunit 1 (COI) gene, and the nuclear ribosomal internal transcribed spacer region (ITS1-5.8S-ITS2).

Morphological and molecular data reveal a new species of Lueheia (Acanthocephala: Plagiorhynchidae) from Turdus migratorius (Turdidae) in central Mexico and its phylogenetic implications within the family.

Members of the genus Lueheia Travassos, 1919, are endoparasites of birds, particularly passerines, throughout the Americas. Adults of Lueheia sp., (Plagiorhynchidae Golvan, 1960; Porrorchinae Golvan, 1956) were recovered from the intestine of the American robin (Turdus migratorius phillipsi Bangs) in Mexico City, and two other species of acanthocephalans identified as Porrorchis nickoli, (Plagiorhynchidae: Porrorchinae) Salgado-Maldonado and Cruz-Reyes, 2002 and Centrorhynchus microcephalus (Bravo-Hollis, 1947) Golvan, 1956 (Centrorhynchidae Van Cleave, 1916), were recovered from the Virginia opossum (Didelphis virginiana Allen) and groove-billed ani (Crotophaga sulcirostris Swainson), respectively in southeastern Mexico.

A New Species of (Nematoda: Coronostomatoidea) Parasite of (Coleoptera: Passalidae) from Mexico, and the Position of the Family in the Oxyuridomorpha.

A new species of the nematode Kloss, 1962 (Oxyuridomorpha), is described from the wood beetle Truqui from the mountain mesophilic forest in Hidalgo State, Mexico. n. sp.

Helminth Community Structure of the Gray Four-Eyed Opossum (Mammalia: Didelphidae) in the Neotropical Portion of Mexico.

Studies on helminth communities associated with didelphids are scarce; the majority of works have focused at taxonomic level. To increase the ecological knowledge of these host-parasite associations, during March (dry season) of 3 consecutive years (2013-2015) a total of 49 adults of the gray four-eyed opossum () was collected in the Neotropical portion of Mexico (Agua Fría, Chiapas State) and examined for helminths. The main objectives of this study were to describe the infra- and component communities of helminths associated with and to compare the helminth fauna of the Mexican population of this host species with those studied in French Guiana and in other Mexican terrestrial didelphids.

Molecular data reveal a new species of Stiles & Hassall, 1898 (Digenea, Echinostomatidae) in the Common opossum, L. (Mammalia, Didelphidae) in the Yucatán Peninsula, Mexico.

A new species of Stiles & Hassall, 1898 is described from the small intestine of the Common opossum, Linnaeus from the Yucatán Peninsula, Mexico. is morphologically very similar to the type species of the genus, (Rudolphi, 1819) Stiles & Hassall 1898, a species widely distributed in opossums across Mexico. A molecular phylogenetic analysis using a mitochondrial gene (cox1), and the nuclear ribosomal internal transcribed spacer region (ITS1-5.

New records of helminths of Cope (Squamata, Phrynosomatidae) from Guerrero and Michoacán, Mexico, with the description of a new species of Seurat, 1914 (Nematoda, Physalopteridae).

A total of 61 specimens of the Red-headed Spiny Lizard Cope (Phrynosomatidae) collected during the breeding season (June/July 2003, 2004 and 2005) from Western Mexico were examined for helminths. The morphological characterization of the helminths found was made through light microscopy and scanning electron microscopy. Nine taxa of helminths were identified, two cestodes: sp.

Two new species of Parapharyngodon parasites of Sceloporus pyrocephalus, with a key to the species found in Mexico (Nematoda, Pharyngodonidae).

Two new species of Parapharyngodon collected from the intestine of the Mexican boulder spiny lizard Sceloporus pyrocephalus are described. This study increases to 49 the number of valid species assigned to Parapharyngodon worldwide, 11 of them distributed in Mexico. Males of the two new species share the presence of four pairs of caudal papillae, an anterior echinate cloacal lip and the presence of lateral alae; however, both differ from each other in lateral alae extension and echinate cloacal anterior lip morphology.

Helminths of three species of opossums (Mammalia, Didelphidae) from Mexico.

From August 2011 to November 2013, 68 opossums (8 Didelphis sp., 40 Didelphisvirginiana, 15 Didelphismarsupialis, and 5 Philanderopossum) were collected in 18 localities from 12 Mexican states. A total of 12,188 helminths representing 21 taxa were identified (6 trematodes, 2 cestodes, 3 acanthocephalans and 10 nematodes).

Parapharyngodon n. spp. (Nematoda: Pharyngodonidae) parasites of hylid frogs from Mexico and review of species included in the genus.

Two new species of Parapharyngodon Chatterji, 1933 , parasitizing 3 species of hylid frogs (Diaglena spatulata, Triprion petasatus, and Trachycephalus typhonius) from Mexico are described. The 2 new species share the presence of a gubernaculum with Parapharyngodon lamothei and belong to the group of those species with short spicule; both differ from the remaining species of the genus in the papillar pattern on ventrolateral and dorsal lips and in the thickness of cuticular annulations and cuticular ornamentation in the female specimens. These are the third and fourth reports of Parapharyngodon spp.

Helminth infracommunity structure of Leptodactylus melanonotus (Anura) in Tres Palos, Guerrero, and other records for this host species in Mexico.

The amphibian genus Leptodactylus includes around 50 species, of which only 2 are distributed in Mexico; the helminth fauna of these 2 species is poorly known. As part of a research program on amphibian parasites in Mexico from 1997 to 2005, 281 sabinal frogs Leptodactylus melanonotus from 42 localities in 11 Mexican states were examined from a helminthological perspective. A total of 20 taxa of helminths-7 digeneans (5 adults, 2 larvae) and 13 nematodes (8 adults, 5 larvae)-was found to infect this amphibian host species.

Gorgoderina festoni n. sp. (Digenea: Gorgoderidae) in Anurans (Amphibia) from Mexico.

Gorgoderina festoni n. sp. is described from the urinary bladder of Gastrophryne usta, Leptodactylus labialis, L.

Species of Gorgoderina (Digenea: Gorgoderidae) in Rana vaillanti and Rana cf. forreri (Anura: Ranidae) from Guanacaste, Costa Rica, including a description of a new species.

Gorgoderina parvicava, G. diaster, and G. megacetabularis n.

[Infracommunity of parasite helminths of Ambystoma lernaensis (Caudata: Ambystomatidae) in Lerma, Mexico].

The helminth infracommunity structure was analyzed in 48 salamanders (Ambystoma lermaensis) from San Pedro Tlaltizapán, Lerma, Estado de Mexico (June 1997 to March 1999). Richness (2.46 +/- 1.