In vitro nematicidal and acaricidal effect of biosurfactants produced by Bacillus against the root-knot nematode Nacobbus aberrans and the dust mite Tyrophagus putrescentiae.

In the present study, the nematicidal and acaricidal activity of three biosurfactants (BS) produced by strains of the Bacillus genus was evaluated. The BS produced by the Bacillus ROSS2 strain presented a mortality of 39.29% in juveniles (J2) of Nacobbus aberrans at a concentration of 30 mg/mL, this same strain is the one that presented the highest mortality in Tyrophagus putrescentiae, which was 57.97% at a concentration of 39 mg/mL. The BS were qualitatively identified by thin layer chromatography and are lipid in nature based on the retention factor (Rf). While the GC-MS analysis identified two main compounds that are 4,7-Methano-1H-indene-2,6-dicarboxylic acid, 3a,4,7,7a-tetrahydro-1, and Methyl 4-(pyrrol-1-yl)-1,2,5-oxadiazole-3-carboxylate1, which is the polar part indicated by the presence of dicarboxylic acid and carboxylate groups; while the non-polar portion can be interpreted as a hydrocarbon chain of variable length. Based on the present results, BS can be an alternative for the biocontrol of the root-knot nematode N. aberrans and the mite T. putrescentiae.

Data from monogenean and endohelminth communities in twospot livebearer Pseudoxiphophorus bimaculatus (Teleostei: Poeciliidae) populations in a neotropical river.

The data presented in this article are related to the research article entitled "Competition from sea to mountain: interactions and aggregation in low diversity monogenean and endohelminth communities in twospot livebearer Pseudoxiphophorus bimaculatus (Teleostei: Poeciliidae) populations in a neotropical river." accepted for publication in Ecology and Evolution. The data describes the communities of helminth parasites in 11 populations of a small poeciliid freshwater fish Pseudoxiphophorus bimaculatus (Heckel, 1848) sampled along the La Antigua river basin in Veracruz, Mexico. We examined 19 P bimaculatus from one locality, 21 from another locality, and 20 from each of the other nine locations sampled in June 2016. A total of 220 individual fish were examined, and in this paper we provide the data for 18 helminth parasite taxa recorded from them. The material in this Data paper comprised the raw data on the abundance, i.e. the number of helminth individuals of each of 18 taxa found in each one individual of P. bimaculatus from each of 11 localities. The data set is contained in a single text-table including one matrix containing each of the 220 host P. bimaculatus examined from 11 localities (lines). Measures for each host P. bimaculatus include total length, standard length, maximum deep and sex, documented for everyone fish examined, plus data of the number of individual helminth of each taxa collected by each examined fish are placed in the columns. These data might be used to examine spatial distribution of helminth parasite taxa. These data might be reused to examine the spatial variation in community structure of helminth parasites of freshwater fish. This kind of data could be used to provide an assessment of human environmental impacts, or for public awareness of conservation objectives.

Dataset on the diversity of helminth parasites of freshwater fish in the headwaters of the Coatzacoalcos river, in Oaxaca, Mexico.

The data presented in this article are related to the research article entitled " Diversity of helminth parasites of freshwater fish in the headwaters of the Coatzacoalcos river, in Oaxaca, Mexico " published in International Journal for Parasitolology: Parasites and Wildlife. This dataset document the diversity of helminth parasites found in 25 fish species from 8 families from rivers in the headwaters of the Coatzacoalcos river basin at the border between Oaxaca and Veracruz states, Isthmus of Tehuantepec zone, southeastern Mexico, in the northernmost end of Central America. We record here 48 species, 44 genera and 29 helminth families. Most of the helminth species recorded in this area has also been collected from Central American bodies of freshwater south of Mexico. The material in this Data in Brief paper comprised the raw data on the abundance distribution of each helminth taxa recorded in each of the host and location; i. e. the number of helminth individuals of each helminth taxa found in each one individual fish from each species from each of the localities sampled. The data set is contained in one text-table matrix per fish-host, date of collection and locality of helminth taxa (lines) per fish host species (columns).

Competition from sea to mountain: Interactions and aggregation in low-diversity monogenean and endohelminth communities in twospot livebearer Pseudoxiphophorus bimaculatus (Teleostei: Poeciliidae) populations in a neotropical river.

The role of interspecific interactions in structuring low-diversity helminth communities is a controversial topic in parasite ecology research. Most parasitic communities of fish are species-poor; thus, interspecific interactions are believed to be unimportant in structuring these communities.We explored the factors that might contribute to the richness and coexistence of helminth parasites of a poeciliid fish in a neotropical river.Repeatability of community structure was examined in parasitic communities among 11 populations of twospot livebearer Pseudoxiphophorus bimaculatus in the La Antigua River basin, Veracruz, Mexico. We examined the species saturation of parasitic communities and explored the patterns of species co-occurrence. We also quantified the associations between parasitic species pairs and analyzed the correlations between helminth species abundance to look for repeated patterns among the study populations.Our results suggest that interspecific competition could occur in species-poor communities, aggregation plays a role in determining local richness, and intraspecific aggregation allows the coexistence of species by reducing the overall intensity of interspecific competition.

Oscheius myriophila (Nematoda: Rhabditida) isolated in sugar cane soils in Mexico with potential to be used as entomopathogenic nematode.

A survey of entomopathogenic nematodes was conducted in sugar cane crops in a total of 14 soils, and positive results were obtained for strain MC5-2014 in the municipality of Tepalcingo, Morelos, in soil with a sandy loam texture and a pH of 6.4. Species determination was performed via morphological and morphometric techniques by searching for a tubular stoma with a swollen cylindrical pharyngeal body and a metacorpus in the basal part. The range of body length (L) was 750 to 1200 µm in females and 720 to 910 µm in males, while the corresponding maximum widths (W) of the body were 30 to 60 µm and 20 to 30 µm, respectively. Males exhibited bursa with a 1 + 1 + 3 + 3 distribution of papillae, and females exhibited a vulva located at the mid-body. For molecular identification, the ITS region of ribosomal DNA was used. Virulence tests (LC50) were conducted with Galleria mellonella, and a value of 4.732 was obtained for infective juveniles (IJs). Taking taxonomic and molecular characteristics into account, the isolate was determined to be Oscheius myriophila. The isolation of this strain represents the first geographic report of O. myriophila in Mexico, and it should be noted that the cultivation of sugar cane occurs with constant application of insecticides, herbicides, fungicides, and fertilizers as well as harvesting activities such as burning of the crop for harvest. The O. myriophila isolate has the potential to be used in the future as a method of biological control in our country.A survey of entomopathogenic nematodes was conducted in sugar cane crops in a total of 14 soils, and positive results were obtained for strain MC5-2014 in the municipality of Tepalcingo, Morelos, in soil with a sandy loam texture and a pH of 6.4. Species determination was performed via morphological and morphometric techniques by searching for a tubular stoma with a swollen cylindrical pharyngeal body and a metacorpus in the basal part. The range of body length (L) was 750 to 1200 µm in females and 720 to 910 µm in males, while the corresponding maximum widths (W) of the body were 30 to 60 µm and 20 to 30 µm, respectively. Males exhibited bursa with a 1 + 1 + 3 + 3 distribution of papillae, and females exhibited a vulva located at the mid-body. For molecular identification, the ITS region of ribosomal DNA was used. Virulence tests (LC50) were conducted with Galleria mellonella, and a value of 4.732 was obtained for infective juveniles (IJs). Taking taxonomic and molecular characteristics into account, the isolate was determined to be Oscheius myriophila. The isolation of this strain represents the first geographic report of O. myriophila in Mexico, and it should be noted that the cultivation of sugar cane occurs with constant application of insecticides, herbicides, fungicides, and fertilizers as well as harvesting activities such as burning of the crop for harvest. The O. myriophila isolate has the potential to be used in the future as a method of biological control in our country.

Diversity of helminth parasites of freshwater fish in the headwaters of the Coatzacoalcos River, in Oaxaca, Mexico.

We documented the diversity of helminth parasites of 25 fish species from 8 families occurring in the headwaters of the Coatzacoalcos river basin. This river flows along the border between the states of Oaxaca and Veracruz, in the region of the Isthmus of Tehuantepec, in south-eastern Mexico, and in northern Central America. We recorded 48 species, representing 44 genera and 29 helminth families. Six of the 25 fish species were examined for helminths for the first time; 60 new host records were reported. Nematodes and trematodes were the most abundant taxonomic groups. The helminth fauna from our study area consists of primarily central American species. Most species recorded from this area have also been captured from freshwater bodies between the Isthmus of Tehuantepec and the Isthmus of Panama. However, three species, including an acanthocephalan and two nematodes, are likely endemic to this area. We argue that, in contrast to the presence of larval helminths, which mostly depends on the geographical location of water bodies, adult helminths are an integral and consistent component of the regional community. Data on taxonomic composition and distribution of helminth fauna reported in this paper, contribute to a better understanding of this faunal component in northern Central America (CA). Furthermore, knowledge of helminth parasites of freshwater fish from Neotropical Mexico and CA facilitates prediction of which parasite species is likely to infect fish in a specific geographical area.

Morphological and Molecular Evidence for a New Rhabdochonid Species (Nematoda: Rhabdochonidae) Parasitizing Profundulus oaxacae (Profundulidae) in the State of Oaxaca, Mexico.

The genus Rhabdochona Railliet, 1916 is one of the most speciose group of nematodes, parasites of freshwater fishes, with approximately 103 species described worldwide. Twenty-two species have been recorded in the Americas, 14 of them in Mexico. In this paper we describe a new species of Rhabdochona on the basis of light and scanning electron microscopy and molecular tools. Rhabdochona adentata n. sp. was recovered from the gallbladder of the freshwater Oaxaca killifish, Profundulus oaxacae (Meek, 1902) (Profundulidae) captured in the Río Grande, State of Oaxaca, Mexico. Rhabdochona adentata n. sp. differs markedly from its congeners by possessing an unusual prostom lacking anterior teeth, small simple deirids, and the location of the excretory pore at the level of the union of the muscular and glandular esophagus. Sequences of cytochrome c oxidase subunit I (COI) from mitochondrial deoxyribonucleic acid and the D2 + D3 domains of the large ribosomal subunit (28S) were obtained from 3 specimens and were analyzed using maximum likelihood and Bayesian inference analyses. Phylogenetic analyses using COI and 28S genes recovered 1 new lineage of Rhabdochona. The new species is described on the basis of a detailed morphological study. This parasite represents the first species of Rhabdochona without prostomal teeth and with a different site of infection, the gallbladder.

A new genus and species of pinworm (Nematoda, Oxyuridae) from the gray mouse opossum, Tlacuatzin canescens.

Tlacuatzoxyuris simpsoni n. gen. n. sp. is described from the cecum of the gray opossum, Tlacuatzin canescens, a species endemic to the deciduous dry forest of Mexico. The digestive tracts of four specimens were examined for parasites; three of these were archived in the American Museum of Natural History and one was a live capture. Relative to the other four monotypic genera of pinworms known to infect opossums, the new genus is diagnosed on the basis of a round cephalic plate with a semicircular stoma surrounded by a rim. In addition, males feature a prominent cephalic vesicle not fully developed in females, accounting for sexual dimorphism. The new species includes small worms that feature a conspicuous, not reticulated cephalic vesicle and semicircular stoma and lateral alae with two crests. In addition, the postcloacal cuticle of males features a small area with ornamentation between cloaca and submedial papillae. Finally, both spicule and gubernaculum are relatively short. Although the eggs of Tlacuatzoxyuris n. gen. are unknown, the conspicuous differences in traits used in the diagnosis of genera prompted us to propose a new genus for the new species. This is the first species of Oxyuridae reported in mouse opossums outside South America, and the fifth species of the family occurring in didelphimorph marsupials. This is an example of the usefulness of documenting the diversity of parasites associated with this unique clade of mammals through the examination of preserved tissues.

Data on monogenean (Platyhelminth) parasites in 11 populations of Astyanax aeneus (Pisces: Teleostei) in a neotropical river in Chiapas, south Mexico.

The data presented in this article are related to the research article entitled "Aggregation and negative interactions in low-diversity and unsaturated monogenean (Platyhelminthes) communities in Astyanax aeneus (Teleostei) populations in a neotropical river of Mexico" publicated in Int. J. Parasitol. Parasites Wildl. 8 (2019) 203-215. https://doi.org/10.1016/j.ijppaw.2019.02.005. This article describes the communities of monogenean parasites in 11 populations of a small characid freshwater fish Astyanax aeneus (Günther) separated by small geographical distances along 60 km of the Lacantún river in Chiapas, Mexico. We examined 15 A. aeneus from each of 11 locations (one sample in February, a second sample in August 2012), situated at the mouth of the streams opening into the main body of the Lacantún river, at the Montes Azules Biosphere Reserve in the Lacandon forest, Chiapas in southern Mexico. The area of study is located ∼800 km from the mouth of the Usumacinta river in the Gulf of Mexico. In this paper we provide the data for 12 monogenean taxa. The material in this Data in Brief paper comprised the raw data on the abundance distribution of each monogenean taxa recorded in each of the locations; i. e. the number of helminth individuals of each of 12 taxa found in each one individual of A. aeneus from each of 11 localities. The data set is contained in a single table text document including one matrix per date of collection and locality of monogenean species (lines) per host A. aeneus (columns).

Aggregation and negative interactions in low-diversity and unsaturated monogenean (Platyhelminthes) communities in Astyanax aeneus (Teleostei) populations in a neotropical river of Mexico.

We studied monogenean communities of 11 populations of Astyanax aeneus (Günther) separated by small geographical distances along 60 km of the Lacantún river in Chiapas, Mexico, in February and August 2012. We found 12 monogenean taxa. Amongst these, five species specialist for Astyanax were widely distributed regionally, constituting 90% of the total collected monogeneans, with one of these species dominating most component communities. The high similarities in terms of composition between the component communities (SJaccard > 60%) as well as in terms of the abundance and composition between infracommunities (SBray Curtis > 40%), provide empirical evidence that transmission, both between hosts at the same location and between component communities, is high and effective. No resemblance pattern was detected between locations in terms of their spatial distribution. The composition of these communities was spatially and temporally consistent over the two very different weather periods sampled. These communities were not saturated. Our analysis suggests that the potential richness of the infracommunities is proportional to the number of monogenean species available in the component community. We found aggregation in the populations and between monogenean species. Intraspecific aggregation is density dependent, suggesting that intraspecific competition for space is not a limiting factor for the development of the population. We evaluated the associations for each species pair and detected 77% negative interactions (134/177 associations), suggesting that interspecific competition plays an important role in shaping these communities. The negative correlations of abundance between pairs of species contributes to confirmation of competition. Intraspecific aggregation increased relative to interspecific aggregation with richness in the component community, facilitating coexistence of the species. Our results suggest that these are interactive communities, where monogeneans disperse efficiently from a common source, colonize patches (hosts) together, and compete with other species even at low population densities. Finally, the coexistence of these species is favored by the unpredictable recruitment and aggregated use of fragmented resources.

Ecto- and endo-parasitic monogeneans (Platyhelminthes) on cultured freshwater exotic fish species in the state of Morelos, South-Central Mexico.

An extensive parasitological study of 365 freshwater exotic fish specimens belonging to 13 species of seven families (Cichlidae, Cyprinidae, Osphronemidae, Pangasidae, Poeciliidae, Characidae, and Loricariidae) collected from 31 Aquaculture Production Units (APU) from Central Mexico revealed the occurrence of 29 ecto- and endo-parasitic monogeneans found on gills and stomachs: Cichlidogyrussclerosus, C.thurstonae, C.tilapiae, Cichlidogyrus sp. 1, Cichlidogyrus sp. 2, Enterogyruscoronatus, E.malmbergi, Gusseviaspiralocirra, Sciadicleithrumiphthimum, Sciadicleithrum sp., Scutogyruslongicornis (all Dactylogyridae), Gyrodactyluscichlidarum, and G.yacatli (Gyrodactylidae) on Oreochromisniloticus, Pterophyllumscalare and Hemichromis sp. (Cichlidae); Dactylogyrusbaueri, D.formosus, D.intermedius, D.vastator, D.extensus, Dactylogyrus sp. (all Dactylogyridae), and G.kobayashii on Carassiusauratus, Cyprinuscarpio and Ctenopharyngodonidella (Cyprinidae); Trianchoratusacleithrium and T.trichogasterium (Dactylogyridae) on Trichogastertrichopterus (Osphronemidae); Thaparocleiduscaecus, T.siamensis (Dactylogyridae), and Dactylogyridae sp. on Pangasianodonhypophthalmus (Pangasidae); G.poeciliae on Poeciliareticulata (Poeciliidae); Diaphorocleidusarmillatus (Dactylogyridae) on Gymnocorymbusternetzy (Characidae); Unilatusunilatus (Dactylogyridae) and Gyrodactylidae sp. on Hypostomus sp. (Loricariidae). The paramount importance of the establishment of these monogeneans due to the importation/exportation of non-native ornamental and other exotic host fish species cultured for food in Mexico is briefly discussed. Quarantine is recommended for all transferred host species.

Host specificity and the structure of helminth parasite communities of fishes in a Neotropical river in Mexico.

In a tropical locality of Río La Antigua, Veracruz, Mexico, 11 fish species, represented by 244 individual fish from six freshwater fish families living sympatrically and synchronically, were examined for helminth parasites. A total of 36 taxa of helminths were recorded, 24 autogenic and 12 allogenic forms, including 6 monogeneans, 14 trematodes, 1 cestode, and 15 nematodes. Most helminth taxa were recovered for 10/11 of the component communities we analyzed. The results contribute empirical evidence that host specificity is an important force in the development of helminth communities of freshwater fishes. Each fish family has their own set of parasites, host species belonging to the same taxon share parasite species. High component community similarity among related host species was recorded, demonstrated by high prevalence and abundance, as well as dominance, of autogenic specialist species in each component community. Most autogenic helminth species are numerically and reproductively successful in relatively few host species. Autogenic helminths common in one host species are not common in others. Our findings give empirical support to the idea that low levels of sharing of parasites favor animal coexistence and high species richness, because large phylogenetic differences allow potentially competing animals to consume the same resources without being sensitive of another's parasites.

Two new species of Aristocleidus (Monogenea) from the gills of the Mexican mojarra Eugerres mexicanus (Perciformes, Gerreidae) from southwestern Mexico.

Aristocleidus mexicanus n. sp. and Aristocleidus lacantuni n. sp. are described from the gills of the Mexican mojarra Eugerres mexicanus (Gerreidae, Perciformes) from the Rio Lacantún basin, Chiapas State, Mexico. These new species differ from previously described congeneric species in the characteristics of several structures, including: (a) ventral anchors, with differences in length (i.e. 46-50 µm in A. mexicanus vs. 38-43 µm, 34-37 µm, and 26-33 µm in Aristocleidus hastatus Mueller, 1936, Aristocleidus sp. of Mendoza-Franco, Violante-González & Roche 2009, and Aristocleidus lamothei Kritsky & Mendoza-Franco, 2008, respectively) and shape (i.e. slightly angular union of elongate arcing shaft and point in A. mexicanus vs. point and shaft united at a conspicuous angular bend in A. hastatus and Aristocleidus sp., and evenly curved shaft and point in A. lamothei); (b) male copulatory organ, i.e. a coiled tube with less than one ring in A. mexicanus and A. lacantuni (vs. a coiled tube of about 1½ in Aristocleidus sp.); (c) distal end of the accessory piece (ornate in A. mexicanus vs. distally flattened and trifid in A. hastatus and A. lamothei, respectively); (d) vaginal tube (moderately long in A. mexicanus vs. short in A. lamothei and looping in Aristocleidus sp.); and (e) ventral bar (anteromedial process with terminal horn-like ornamentation in A. lacantuni vs. ornamentation absent in the other species). This study reports for the first time species of Aristocleidus from freshwater environments in Mexico.

Two new species of Urocleidoides Mizelle et Price, 1964 (Monogenoidea) from the gill lamellae of profundulids and poeciliids from Central America and southern Mexico.

During investigations of gill ectoparasites (Platyhelminthes) parasitising freshwater fish from Central America (Guatemala, Honduras, El Salvador and Panama) and southeastern Mexico (Guerrero, Oaxaca and Chiapas), the following dactylogyrid monogenoidean were found: Urocleidoides simonae sp. n. from Profundulus punctatus (Günther) (type host), Profundulus balsanus Ahl, Profundulus guatemalensis (Günther), Profundulus kreiseri Matamoros, Shaefer, Hernández et Chakrabarty, Profundulus labialis (Günther), Profundulus oaxacae (Meek), Profundulus sp. 1 and Profundulus sp. 2 (all Profundulidae); Urocleidoides vaginoclaustroides sp. n. from Pseudoxiphophorus bimaculata (Heckel) (type host) and Poeciliopsis retropinna (Regan) (both Poeciliidae); and Urocleidoides vaginoclaustrum Jogunoori, Kritsky et Venkatanarasaiah, 2004 from P. labialis, Profundulus portillorum Matamoros et Shaefer and Xiphophorus hellerii Heckel (Poeciliidae). Urocleidoides simonae sp. n. differs from all other congeneric species in having anchors with well-differentiated roots, curved elongate shaft and short point. Urocleidoides vaginoclaustroides sp. n. most closely resembles U. vaginoclaustrum, but differs from this species mainly in the shape of its anchors (i.e. evenly curved shaft and short point vs curved shaft and elongate point extending just past the tip of the superficial anchor root). The complexity of potential hosts for species of Urocleidoides and their effect on its distribution on profundulid and poeciliid fishes are briefly discussed.

A new species of Torrestrongylus (Trichostrongylidae, Anoplostrongylinae) from Macrotus waterhousii (Chiroptera: Phyllostomidae) in Central Mexico.

A new species of nematode, Torrestrongylus tetradorsalis n. sp., is described herein, based on specimens recovered from the small intestine of the leaf-nosed bat, Macrotus waterhousii, from the Biosphere Reserve "Sierra de Huautla" in the state of Morelos, Mexico. The new species is included in Torrestrongylus because it features a bursa of the type 3 - 2, a divided cephalic vesicle with an anterior half in the shape of an umbrella, and a posterior widened half. The new species can be distinguished from the only other congener T. torrei Pérez-Vigueras, 1935 by four key features: first, by the absence of cervical alae in both males and females; second, by the relatively longer second half of the cephalic cap; third, by the configuration of the dorsal ray, that does not have a medial terminal ray, and finally, by the structure of the spicules. This is the second species in the genus, previously known from bats of the families Phyllostomidae and Molossidae in Cuba, and now in Mexico.

First record of the invasive Asian fish tapeworm Bothriocephalus acheilognathi in Honduras, Central America.

This paper provides the first report of the invasive Asian fish tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934, in Honduras. The cestode was found in Profundulus portillorum (Cyprinodontiformes: Profundulidae), which represents a new host record, and which is a member of a genus faced with a variety of conservation challenges, now potentially complicated by the presence of this pathogenic cestode. Nearly complete sequence data from the ITS-1 5.8S and ITS-2 regions corroborate the determination based on morphological characteristics. Several species of carp were introduced to Honduras for aquaculture purposes in the early 1980s and the presence of the Asian fish tapeworm in Honduras may be related to these introductions. In addition, this report documents the currently known geographical distribution of this parasite in Central America, first recorded from Panamá and now from Honduras.

The communities of helminth parasites of Heterandria bimaculata (Teleostei: Poeciliidae) from the upper Río La Antigua basin, east-central Mexico show a predictable structure.

We investigated a basic generalization in parasite community ecology stating that stochastic processes played a major part in determining the composition of helminth communities of freshwater fish, or on the contrary, if these communities are predictable, diverse and structured species assemblages. We determined the species pool of helminth parasites of a tropical freshwater fish Heterandria bimaculata in its heartland, the upper Río La Antigua basin in east-central Mexico. Approaching our data from the metapopulation standpoint we studied the spatial patterns, and examined the variation in composition and richness of the component communities across different locations. We tested the prediction that helminth species may be recognized as common or rare; and also two hypotheses anticipating depauperate communities and decay of similarity between component communities with increasing distance. We found these communities composed by a highly structured and predictable set of specialist autogenic helminth species that are constant and abundant, dominating all components throughout space. The prediction that it is possible to recognize common and rare species was met. Richer than expected communities were found, as well as highly homogeneous component communities, where neighbouring components were more similar than distant ones. We speculated that the processes shaping the development of these component communities include stable, predictable habitats through time, allowing for a slow gradual dispersion process limited by host and parasite species capabilities. Our study suggests that metapopulation theory can assist in the prediction of community composition and in the understanding of spatial and temporal community variability.

Pterygodermatites (Pterygodermatites) mexicana n. sp. (Nematoda: Rictulariidae), a parasite of Balantiopteryx plicata (Chiroptera) in Mexico.

A new species of nematode, Pterygodermatites (Pterygodermatites) mexicana n. sp., is described based on specimens recovered from the intestine of the gray sac-winged bat, Balantiopteryx plicata (Chiroptera, Emballonuridae), from the Biosphere Reserve "Sierra de Huautla" in the state of Morelos, Mexico. This is the second species in the genus described from bats in the New World, since most of the rictaluriids reported in these hosts belong to the closely related genus Rictularia Froelich, 1802. However, members of Rictularia possess only a single oesophageal tooth at the base of the buccal capsule, whereas in the current nematodes three conspicuous oesophageal teeth are present. They are therefore included in Pterygodermatites Wedl, 1861. The new species is characterized by the presence of 23 small denticles on the periphery of the buccal capsule and by the presence of 40 and 66 pairs of cuticular processes in males and females, respectively. Additionally, males possess 3-4 ventral precloacal fan-like processes, and the cuticular processes of females are divided into 40 pairs of comb-like and 26 pairs of spine-like processes; the vulva opens on the level of approximately pair 40. The dorsally directed stoma and the 40 prevulvar cuticular processes makes it difficult to place the species in any of the subgenera present in the New World, yet characters correspond with the diagnosis of Pterygodermatites (Pterygodermatites) in the Mediterranean region and North Africa.

A new spirurid (Nematoda) parasite from mormoopid bats in Mexico.

A new nematode species, Spirura mexicana n. sp., is described from specimens recovered from the esophageal mucosa of the Parnell's mustached bat Pteronotus parnellii , Davy's naked-backed bat Pteronotus davyi, Wagner's mustached bat Pteronotus personatus, and the ghost-faced bat Mormoops megalophylla in the State of Morelos, Mexico. This nematode is characterized by having a relatively short prostoma, 5-6 pairs of caudal papillae, and a smooth distal end of the tail in females. This is the first species of Spirura described from bats in the New World.

A new allocreadiid (Trematoda) species from freshwater fish Heterandria bimaculata (Teleostei: Poeciliidae) in Southeastern Mexico.

Paracreptotrema heterandriae n. sp. (Trematoda: Allocreadiidae) is described from the intestine of the freshwater fish Heterandria bimaculata (Teleostei: Poeciliidae) from the upper basin of Río La Antigua, in Veracruz, Mexico. The new species is distinguished from the 3 others in the Paracreptotrema Choudhury, Pérez-Ponce de León, Brooks, and Daverdin, 2006 , mainly by having a feeble membranous cirrus sac containing an uncoiled seminal vesicle, instead of a well-developed muscular cirrus sac that encloses coiled seminal vesicle, pars prostatica, and ejaculatory duct as in the previously 3 nominal species. Moreover, eggs of the new species are larger than all others ([measurements in micrometers] eggs of P. heterandriae n. sp. 72.5 [70-75] × 40 [35-41]; P. blancoi 55.4 [52.5-62.5] × 38.5 [32.5-42.5]; P. mendezi 46 × 37; P. profundulusi 57 [52-60] × 27.8 [25-30]).