Rosario Mata-López

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. sp. are reported inhabiting the urinary bladders of Rana vaillanti and R. cf. forreri from northwestern Costa Rica. Gorgoderina megacetabularis n. sp. differs from all other species of the genus by the combination of the following characters: small body size (2.78–3.17, mean 2.92 mm), sucker ratio (1:3.1– 3.7), and by the presence of 2 compact, oval, unlobed vitelline masses. Redescription of G. diaster including previously undescribed details on the reproductive apparatus and morphometric data is provided. This is the first record of the 3 species of Gorgoderina in Costa Rica and is the first record of G. diaster in R. vaillanti and R. cf. forreri.

Comparative Study of the Tegumental Surface of Several Species of Gorgoderina Looss, 1902 (Digenea: Gorgoderidae), as Revealed by Scanning Electron Microscopy

Abstract Seven species representing Gorgoderidae Looss, 1899, previously have been examined by scanning electron microscopy. This study describes the papillary pattern on the body surface of 6 additional species—Gorgoderina attenuata, Gorgoderina bilobata, Gorgoderina diaster, Gorgoderina megalorchis, Gorgoderina parvicava, and Gorgoderina megacetabularis—from localities in the United States, Mexico, and Costa Rica. Four types of papillae (button, ciliated, rosette, and domed) were distinguished on the body surfaces of these trematodes and both the type and position of papillae varied among species. A consistent papillary pattern on the ventral forebody region and oral and ventral suckers is described. Three constant pairs of button papillae are around the stylet cavity. The pattern on the oral sucker consists of 10 papillae around the oral aperture. One of these pairs was doubled in G. bilobata and G. diaster; in addition, a variable number of papillae arranged in groups were usually present. Five pairs of button papillae were always present in a lateral position on the ventral surface of the forebody between both suckers. Six rosette papillae were observed on the ring of the ventral sucker, except in G. megacetabularis; 4 additional pairs of rosette papillae and 2 pairs of domed papillae were observed on the internal surface of this sucker. These papillae were not observed in G. bilobata and G. parvicava. Differences in the papillary pattern among species lie in the position of the different types of papillae.

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

Abstract:  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. parasitizing hylid frogs. In addition to the egg characteristics, we propose that length of the lateral alae is also a taxonomically relevant feature to differentiate species of the genus. A bibliographic review of all species historically assigned to Parapharyngodon is given, including those that have been declared species inquirenda, or transferred to other genera and those that are considered valid.

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. melanonotus and Bufo marinus from localities at low altitude in the states of Veracruz, Oaxaca, Guerrero and Colima, Mexico. This species differs from most other species of the genus by a combination of the following characters: lobed vitelline masses, body size 3.45–4.26 (mean 3.75) mm and sucker-ratio 1:1.3–1.52 (mean 1:1.44). The new species shares these three features with G. bilobata Rankin, 1937, G. schistorchis Steelman, 1938, G. tenua Rankin, 1937, G. vitelliloba (Olsson, 1876) and G. cryptorchis Travassos, 1924, but it differs from the first four in having gonads with entire margins. G. festoni most closely resembles G. cryptorchis, but differs from this species in body width at the level of the ventral sucker and in the absence of oesophageal glands. The autapomorphy that distinguishes G. festoni from all other members of the genus is the presence of a tegumental extension (festoon) on the external margin of the ventral sucker.

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

Abstract 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. Females of both species have a prebulbar uterus and eggs shell punctuate with pores, characteristics shared with few other species of Parapharyngodon. Both new species differ from other congeneric species in the papillar arrangement, the anterior cloacal lip morphology, the lateral alae extension and total length/spicule ratio. A taxonomic key for the species of Parapharyngodon distributed in Mexico is provided.

Helminth Infracommunity Structure of Leptodactylus melanonotus (Anura) in Tres Palos, Guerrero, and Other Records for This Host Species in Mexico

Abstract: 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. These data represent 105 new locality records, and 11 taxa are recorded in L. melanonotus for the first time. Infracommunity analyses of the sabinal frogs from Tres Palos indicated that these hosts are depauperate. The helminth community is dominated by specialist species, with Cosmocerca podicipinus the most common in almost 50% of the infracommunities. Percutaneous infection and predator-prey interactions were the 2 most common infection routes by helminths in frogs from Tres Palos, with 79% of the parasites recruited via skin penetration. Finally, our results show that the helminth fauna parasitizing L. melanonotus throughout Mexico has low similarity with the helminth fauna of leptodactylids studied comprehensively in South America, with only 2 digeneans and 3 nematodes being shared by hosts from both regions. As a result of our survey, the number of helminth species parasitizing L. melanonotus increased to 34. Considering its native distribution range, this number is now 36 with the inclusion of the nematodes Oswaldocruzia costaricensis and Cruzia empera in Costa Rica.

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

Abstract From August 2011 to November 2013, 68 opossums (8 Didelphis sp., 40 Didelphis virginiana, 15 Didelphis marsupialis, and 5 Philander opossum) 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). Sixty-six new locality records, 9 new host records, and one species, the trematode Brachylaima didelphus, is added to the composition of the helminth fauna of the opossums in Mexico. These data, in conjunction with previous records, bring the number of taxa parasitizing the Mexican terrestrial marsupials to 41. Among these species, we recognized a group of helminths typical of didelphids in other parts of the Americas. This group is constituted by the trematode Rhopalias coronatus, the acanthocephalan Oligacanthorhynchus microcephalus and the nematodes Cruzia tentaculata, Gnathostoma turgidum, and Turgida turgida. In general, the helminth fauna of each didelphid species showed a stable taxonomic composition with respect to previously sampled sites. This situation suggests that the rate of accumulation of helminth species in the inventory of these 3 species of terrestrial marsupials in the Neotropical portion of Mexico is decreasing; however, new samplings in the Nearctic portion of this country will probably increase the richness of the helminthological inventory of this group of mammals.

Helminth Infracommunities of the Montezuma's Frog Lithobates montezumae (Anura: Ranidae) in the Nearctic–Neotropical Transition Zone of Mexico

Abstract Thirty specimens of the Montezumas frog Lithobates montezumae were collected in San Pedro Tlaltizapán, in the Nearctic–Neotropical transition zone of Mexico, in April 2013, in order to establish the helminth infracommunity structure harbored by this amphibian host. A total of 5,493 individual helminths were obtained, representing 6 species (3 trematodes and 3 nematodes). The depauperate structure of the helminth infracommunities established for the studied frogs herein (richness = 2.4; mean abundance = 183.1; Brillouins diversity = 0.42) fits with those described for the 6 Ranidae species studied in the Nearctic. Three of the 6 species of helminths recovered are generalists, 2 of them with the highest values for prevalence (Falcaustra mexicana) and mean abundance (Renifer sp.). The parasite recruitment process (ingestion) determining mean richness in the helminth infracommunities studied here (ingestion) is shared with those reported for the 9 Mexican frog species for which helminthological records exist; however, in this case, mean abundance was determined by directly penetrating species. The use of aquatic habits by this anuran species likely explains why the composition of their helminth infracommunities was mainly constituted of helminths acquired in this environment (5 of 6 species). Finally, the heterogeneity of their taxonomic composition and abundance of helminth species indicate the unpredictable nature of these host–parasite associations.

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

Abstract A total of 61 specimens of the Red-headed Spiny Lizard Sceloporus pyrocephalus 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: Mesocestoides sp. and Oochoristica sp., and seven nematodes: Parapharyngodon ayotzinapaensis Garduño-Montes de Oca, Mata-López & León-Règagnon, 2016, Parapharyngodon tikuinii Garduño-Montes de Oca, Mata-López & León-Règagnon, 2016, Parapharyngodon sp., Physalopterinae gen. sp., Skrjabinoptera scelopori Caballero-Rodríguez, 1971, Strongyluris similis Caballero, 1938 and a new species of Thubunaea Seurat, 1914. Larvae of Mesocestoides sp. and Physalopterinae gen. sp. were found in the body cavity and digestive tract, respectively. Excluding the species of Parapharyngodon Chatterji, 1933, S. pyrocephalus is recorded for the first time as a host of the remaining seven taxa of helminths. Additionally, Thubunaea leonregagnonae sp. n. is described and illustrated as a new nematode species, parasite of S. pyrocephalus from Mexico. This new species can be differentiated from the majority of its congeners by the absence of spicules, the particular pattern of caudal papillae in males and the small ratio of oesophagus length:male total body length (0.1–0.16).

Genetic Divergence of Oligacanthorhynchus microcephalus (Acanthocephala: Archiacanthocephala: Oligacanthorhynchidae), Parasite of Three Species of Opossum (Mammalia: Didelphidae) across Central and Southeastern Mexico

ABSTRACT:  Oligacanthorhynchus (Rudolphi, 1819) Schmidt, 1972 (Oligacanthorhynchidae) is a typical parasite of opossums (Didelphidae). This species of acanthocephalan exhibits a wide distributional range that extends from Brazil to as far north as the United States, but no data on the genetic divergence of this helminth has been provided thus far along its entire geographic range. The facts that O. microcephalus shows a relatively wide geographic range in Mexico and that it has been recorded in 3 species of opossum allowed us to conduct a molecular prospecting study to assess the genetic divergence among individuals and populations as well as to detect potentially exclusive lineages indicative of the presence of a species complex. In total, 81 specimens identified as O. microcephalus were collected from the intestines of 3 species of opossum in 8 localities across central and southeastern Mexico. The DNA sequences of 2 genes were generated; cytochrome c oxidase subunit 1 (cox 1) of the mitochondrial DNA and the domains D2 and D3 from large subunit of the nuclear ribosomal RNA (LSU). Maximum parsimony, maximum likelihood, and Bayesian inference analyses were performed for each dataset alone and for the combined datasets (LSU + cox 1). All the phylogenetic analyses yielded 3 major clades with high bootstrap and posterior probability support values and with relatively high genetic divergence levels for both markers. However, the morphological study of specimens through both light and scanning electron microscopy, as well as the morphometric data, indicate that those specimens allocated into Clade I are smaller than those contained in Clades II and III. Lower genetic divergence values, as well as no clear-cut morphometric differences, indicate that Clades II and III are likely not independent lineages. Our results show at least 2 genetic lineages that may represent independent species, but we refrain at the moment on describing a new species in the lack of evidence gathered from a wider geographic range.