Search

The helminth community of Lithobates spectabilis (n =77) was studied from Las Pilas (low altitude) and Metznoxtla (high altitude), Biosphere Reserve Barranca de Metztitlán, Hidalgo, Mexico. Species diversity was compared at the infracommunity and the component community level using Hill numbers, and the beta diversity was calculated. Five species of Digenea, 5 of Nematoda, and 2 of Acanthocephala were found in the frogs from the 2 localities. The species richness of parasites in Las Pilas (9 species) was higher than that of Metznoxtla (7 species). The helminth community in Las Pilas was dominated by nematodes and, in Metznoxtla, it was dominated by digeneans. The most prevalent species in Las Pilas was Foleyellides cf. flexicauda (65% of frogs were infected) and, in Metznoxtla, it was Megalodiscus americanus (76% were infected). Glypthelmins quieta was the species with the highest mean abundance in both localities (Las Pilas = 4.5; Metznoxtla = 11.0). The difference in species composition between the 2 localities was significant (Anosim; R = 0.54, p < 0.05). The differences in the composition of species of helminths between the 2 localities suggest that local environmental conditions are different, which may reflect differences in local host diet.

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations. Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods.

As a part of an ongoing project to inventory the helminth parasites of rodents in Mexico, 30 individuals of Aspiculuris americana were collected inhabiting the intestine from three specimens of the rock mouse Peromyscus difficilis, collected from Cerro Xihuingo, Municipality of Tepeapulco, Hidalgo State, Mexico. This species of nematode parasite different species of the genus Peromyscus (P. gossypinus, P. leucopus, P. maniculatus, and P. floridanus) distributed from Yukon Territory in Canada to Florida in the United States of America. This is the first report of Aspiculuris americana in a Mexican endemic rodent, widening the known distribution of the species to the southern portion of the country.

To determine levels of metal bioaccumulation (Cd, Cr, Pb and Al) in weaves and corporal fluids of the inhabitants of Xochitlán, Hidalgo, has been the objective of this study. With a view to realising valuations of risk and probable damages to the health of its settlers, the study with a sociodemographic characterization began, with settlers between 6 and 90 years of age. As exclusion criterion were considered, congenital malformations, immunosuppressive sufferings and less than five years of residence in the locality. An inverted population pyramid appeared; of a total of 1947 inhabitants, the population between 10 and 19 years occupies the center of the pyramid, that thins in the ends of the life (5> X> 60 years). A methodology, combined with the established by the ATSDR and the EPA has seted out and adding an instrument of survey (clinical anamnesis) for the characterization of individuals and populations with ample clinical approach. Of the interrelation of flowed and woven metal concentrations in, with aspects of environmental risks it will be possible to be poured off a present, retrospective situational diagnosis and a vision to future, on the behaviour of the contamination and its impact in health factors. The evaluated metal bioaccumulation was present in all the fluids and weaves of the settlers selected between 6 and 90 years of age. One has been a probable relation between these results and those of previous studies of metal accumulation in waters, grounds and cultures.

Species of Acanthobothrium have been documented as parasites of the spiral intestine of elasmobranchs. Results of a metadata analysis indicate that 114 species of elasmobranchs have been reported as hosts of 200 species of Acanthobothrium. The metadata analysis revealed that 3.7% of species of sharks and 14.9% of species of rays that have been reported as hosts to date; some species are parasitized by more than one species of Acanthobothrium. This work provides a Category designation, as proposed by Ghoshroy and Caira (2001), for each species of Acanthobothrium. These Category designations are a tool to facilitate comparisons among members of Acanthobothrium for descriptions of new species in the future.

Three new species of Acanthobothrium Blanchard, 1848 (Onchoproteocephalidea: Onchobothriidae) are described from Pacific coastal waters of Mexico. Based on four criteria for categorization of species of Acanthobothrium, the three new species belong to Category 2 species, characterized by their total length (< 15 mm), number of proglottids (< 50) and testes (

The present study was carried out to determine the effect of tilapia Oreochromis niloticus on the physical and chemical sediment parameters on an earthen pond in monoculture (shrimp Penaeus vannamei) and co-culture (tilapia-shrimp) during the dry and wet seasons in a commercial farm during the period from mid-September to end-December 2017 and February to mid-May 2018. Chemical and physical analyses were realized on sediment samples from brackish water ponds representing shrimp farms in San Blas Nayarit, Mexico. Concentrations of organic carbon, nitrogen, potassium, magnesium and calcium were higher in co-culture ponds, and there was a tendency to a higher concentration of phosphorus and sodium in the sediment of monoculture ponds. The texture of the ponds showed a tendency in the dry season to increase the percentage of clay in co-culture due to the effect of bioturbation caused by tilapia. There was no evidence of poor development of sediment quality in any treatment. It was found that tilapia was a factor that affected sediment quality, differences in growth between shrimp monoculture and tilapia-shrimp co-culture can be explained, at least in part, by differences in their sediment.

En el presente trabajo se determinó la presencia y concentraciones de los pesticidas organoclorados (PO), en agua y sedimentos de Laguna de Metztitlán, Hidalgo; con el objetivo de identificar el uso de estos compuestos como un factor de presión sobre la biodiversidad y un potencial de riesgo asociado a la salud, problemática que se acentúa debido a que inmerso en la reserva hay asentamientos humanos y que la principal actividad económica de la región es la agricultura. Para su evaluación se tomaron cinco muestras compuestas de agua en la Laguna de Metztitlán en el 2016 y una en la desembocadura del Río Metztitlán, tanto en época de sequía como de lluvia, bajo los lineamientos de la NMX-AA-003-1980. Se analizaron de manera individual por triplicado por cromatografía de gases y espectrofotometría de masas. Los resultados corroboran lo reportado bibliográficamente, además de que a las concentraciones observadas hay un potencial de riesgo para la salud y la biodiversidad, lo cual implica la necesidad de monitorear la zona permanentemente para evaluar la presencia y concentración de estos compuestos, así como su potencial impacto en el ambiente y en la población.

Biotic or abiotic factors responsible for temporal or spatial variation in metazoan parasite communities of the green jack Caranx caballus were studied over a nine-year period using samples collected at locations along the south-central Pacific coast of Mexico. A total of 708 fish were collected from six locations between December 2009 and October 2017. Thirty-two parasite species were identified: three Monogenea, nine Digenea, two Cestoda, five Nematoda, eight Copepoda, and three Isopoda. At the component community level, parasite species richness varied significantly from seven (Zihuatanejo 2016) to 18 (Acapulco Bay 2011). The component communities and infracommunities of C. caballus exhibited a similar pattern: low species numbers, low diversity, and dominance by a single species (mainly the monogenean Pseudomazocraes selene or the digenean Bucephalus varicus). Parasite community structure and species composition varied between locations and/or sampling years. The main factors responsible for t...

Violante-González, Juan, Santos-Bustos, Nataly G., Monks, Scott, Pulido-Flores, Griselda, García-Ibáñez, Sergio, Rojas-Herrera, Agustín A. (2018): Parasite community of the golden cownose ray Rhinoptera steindachneri Evermann and Jenkins 1891 (Chondrichthyes: Myliobatidae), in Acapulco Bay, Guerrero, Mexico. Journal of Natural History 52 (17-20): 1115-1131, DOI: 10.1080/00222933.2018.1452305, URL: http://dx.doi.org/10.1080/00222933.2018.1452305

Parasite communities in Caranx sexfasciatus were characterized and analyzed to determine any interannual variations in structure and/or species composition. In total, 422 C. sexfasciatus were collected from Acapulco Bay, Mexico, between May 2016 and March 2019. Thirty-two taxa of metazoan parasites were identified: five Monogenea, thirteen Digenea, one Acanthocephala, one Cestoda, three Nematoda, seven Copepoda, and two Isopoda. Monogeneans were the most frequent and abundant parasite species in all sampling years. Parasite species richness at the component community level varied significantly from 8 (May 2016) to 25 (March 2019) and was similar to previous reports for other species of Carangidae. The component communities and infracommunities in C. sexfasciatus were characterized by low parasite species numbers, low diversity, and dominance of a single species (the monogenean Neomicrocotyle pacifica). Parasite community structure and species composition varied between sampling years and climatic seasons. Seasonal or local fluctuations in some biotic and abiotic environmental factors probably explain these variations.Variation interannuelle des communautés de parasites métazoaires de la carangue à gros yeux Caranx sexfasciatus (Pisces, Carangidae).Les communautés de parasites de Caranx sexfasciatus ont été caractérisées et analysées afin de déterminer si elles connaissent des variations interannuelles dans la structure et/ou la composition des espèces. Au total, 422 C. sexfasciatus ont été collectés dans la baie d’Acapulco, au Mexique, entre mai 2016 et mars 2019. Trente-deux taxons de parasites métazoaires ont été identifiés : cinq Monogenea, treize Digenea, un Acanthocephala, un Cestoda, trois Nematoda, sept Copepoda et deux Isopoda. Les monogènes étaient les espèces de parasites les plus fréquentes et les plus abondantes au cours de toutes les années d’échantillonnage. La richesse en espèces de parasites au niveau de la communauté des composants variait considérablement de 8 (mai 2016) à 25 (mars 2019) et était similaire aux rapports précédents pour d’autres espèces de Carangidae. Les communautés et infracommunautés de C. sexfasciatus étaient caractérisées par un faible nombre d’espèces de parasites, une faible diversité et la dominance d’une seule espèce (le monogène Neomicrocotyle pacifica). La structure des communautés de parasites et la composition des espèces variaient entre les années d’échantillonnage et les saisons climatiques. Les fluctuations saisonnières ou locales de certains facteurs environnementaux biotiques et abiotiques expliquent probablement ces variations.

Aim of study: To determine the effects of white shrimp (Litopenaeus vannamei) and tilapia nilotica (Oreochromis niloticus var. Spring) in monoculture and co-culture on water quality variables and production in earthen ponds during dry and rainy seasons.Area of study: A shrimp farm (total area 20 ha) at Chiripa, San Blas Nayarit, Northwest coast of Mexico (21° 37' 34.53 " N; 105° 18' 16.31" W).Material and methods: Two production cycles were performed in a completely randomized design consisting of two treatments and three replications each during rainy season (September-December) and dry season (February-May). Shrimp was the main crop and tilapia the secondary species.Main results: White shrimp (10 org/m2) can be co-cultured with Nile tilapia at a stocking high density (4 org/m2), leading to improved water quality and better utilization of nutrients in dry season than in rainy season. However, the shrimp’ highest weight was recorded in the tilapia-shrimp co-culture ponds during rainy season due to higher water temperature and better quality of live food. The mean individual weight, biomass and survival of the shrimp, in co-culture ponds were greater than those of the shrimp monoculture, in the two seasons studied.Research highlights: There was a trend towards greater concentration of nutrients in the water of the monoculture ponds and, lower dissolved oxygen and higher BOD5 in co-culture ponds in the dry season than in the rainy season.

In recent years, Mexico uses 76.3% of the available water for food production. Aquaculture is an important animal protein production activity with an annual growth of 6.6%. Hidalgo is the second landlocked state in fish production. The national aquaculture official reports 967 production units, which are divided in intensive, semi-intensive, and extensive production levels. The main aquaculture resources produced in Hidalgo include Carpa (4606 tons), Mojarra (4015 tons), Trucha (173 tons), and Bagre (24 tons). The objective of this chapter is to present a broad vision of the water management sustainability of aquatic resources and its impact from various economic, social, and environmental points of view, in a short-term perspective.

Specimens of Xiphophorus birchmanni (Teleostei: Poeciliidae) (55 individuals) (Sheepshead swordtail) were collected from 2 localities in the Panuco River drainage from Hidalgo and Veracruz [at Atlatipa (n = 26) and Benito Juarez (n = 29), respectively], Mexico. The structure of the parasite communities of fish from the 2 localities was examined and compared. Helminths from 10 taxa were recovered: 6 species of larval digeneans ( Posthodiplostomum sp., Uvulifer sp., Centrocestus formosanus, Ascocotyle sp., Haplorchis pumilio , and Echinostomatidae gen. sp.); 2 adult monogeneans ( Urocleidoides vaginoclastrum and Gyrodactylus sp.); 1 larval cestode (metacestode stage; Glossocercus auritus ); and 1 larval nematode, Eustrongylides sp. Urocleidoides vaginoclastrum and C. formosanus were the most frequent and abundant species. The remaining taxa were rare and found at low mean abundance. Component community and infracommunity differences observed in this study could be attributed to abiotic and biotic environmental factors resulting from the geographic separation of these localities during the orogeny of the Sierra Madre Oriental that restricted fish to isolated localities.

Population dynamics is a branch of ecology that studies temporal changes in the abundance of a population of organisms over time. This paper presents a study of the factors influencing population abundance of the acanthocephalan Neoechinorhynchus brentnickoli in Dormitator latifrons, the Pacific fat sleeper, from Tres Palos Lagoon. Fish were sampled from February 2012 to February 2013. A total of 688 adult fish were examined. The mean total length of fish varied significantly from 16.10 ± 1.93 cm (September 2012) to 20.78 ± 3.82 cm (August 2012). ‘Prevalence of acanthocephalans exceeded 90% in all months, and mature individuals were present year round, indicating that recruitment of helminths occurred throughout the year. Mean abundance ranged from 32.3 (July 2012) to 89.3 helminths per fish (March 2012) and was significantly lower in the rainy season. The body size of fish was the best predictor of acanthocephalan abundance in every month; larger fish harbored more acanthocephalans than smaller o...

Two species of Acanthobothrium (Onchoproteocephalidea: Onchobothriidae) are described from the spiral intestine of Narcineentemedor Jordan & Starks, 1895, in Bahía de Acapulco, Acapulco, Guerrero, Mexico. Based on the four criteria used for the identification of species of Acanthobothrium, A.soniaesp. nov. is a Category 2 species (less than 15 mm in total length with less than 50 proglottids, less than 80 testes, and with the ovary asymmetrical in shape). Acanthobothriumvidalisp. nov. is a Category 6 species (more than 15 mm in total length with more than 50 proglottids, fewer than 80 testes, and the ovary is asymmetrical). The new species differ from similar species from the Pacific Ocean by total length, the number of proglottids, diameter of the accessory sucker, the length of the cirrus sac, the number of testes per proglottid and the measurements of hooks. With the recognition of A.soniaesp. nov. and A.vidalisp. nov., 42 species of Acanthobothrium have been reported from the Pacific coast of the Americas. This is the first report of species of Acanthobothrium from a member of Narcine from Mexico and it brings the number of species reported from elasmobranchs from the Pacific Coast of Mexico to 13.

Neonchocotyle violantei n. sp. (Monogenea: Hexabothriidae) infects the gill of the Atlantic guitarfish, Pseudobatos lentiginosus (Rhinopristiformes, Rhinobatidae) from littoral waters of Celestún, Yucatán, Mexico. It is assigned to Neonchocotyle because it has, among other features, an asymmetrical haptor, a seminal receptacle, a smooth oötype, and an egg with two elongate filaments. It differs from Neonchocotyle pastinacae, the only congener, by having a small body (821 long by 315 wide, length to width = 2.6:1), two pairs of microhooks between the haptoral appendix suckers, extracaecal (submarginal) vaginal pores, and 5-9 testes. This is the first record of a species of Neonchocotyle in the Gulf of Mexico, the first monogenean reported from P. lentiginosus in Mexico and the second species of Hexabothriidae reported from Mexico. Resumo Neonchocotyle violantei n. sp. (Monogenea: Hexabothriidae) infecta brânquia de Pseudobatos lentiginosus, (Rhinopristiformes, Rhinobatidae) de águas litorâneas ao largo da costa de Celestún, Yucatán, México. É atribuído a Neonchocotyle porque tem, entre outras características, um haptor assimétrico, um receptáculo seminal, um tipo oótipo liso e um ovo com dois filamentos alongados. Difere de Neonchocotyle pastinacae, o único congênere, por ter um corpo pequeno (821 de comprimento por 315 de largura, comprimento a largura = 2,6: 1), dois pares de microganchos entre as ventosas do apêndice haptoral, poros vaginais extracaecais (submarginal) e 5-9 testículos. Este é o primeiro registro de uma espécie de Neonchocotyle no Golfo do México, o primeiro monogenético registrado em P. lentiginosus no México e a segunda espécie de Hexabothriidae relatada no México.

Denarycotyle gardneri n. gen., n. sp. (Monogenea: Monocotylidae) is described from the gills of the stingray, Rhinoptera steindachneri (Myliobatidae), collected in marine waters off Acapulco, Guerrero, Mexico. The genus is assigned to Euzetiinae because it has a haptor with one central loculus, one additional loculus on either side of the central loculus and 10 peripheral loculi. However, the genus described herein can be distinguished from Euzetia, the only genus currently assigned to Euzetiinae, by the presence of two accessory structures on the dorsal surface of the haptor and hamuli with a sclerotized accessory piece on each hamulus. Specimens of D. gardneri n. gen., n. sp. were found on the gills of 4 of 18 individuals of R. steindachneri (22%) but were not present on Rhinobatos glaucostigma Jordan and Gilbert (1 individual), Urotrygon rogersi (Jordan and Starks) (2), Narcine entemador Jordan and Starks (3), Aetobatus narinari (Euphrasen) (1) or Dasyatis longa (Garman) (3). This is the third genus and the fourth species of a monogenean recorded from Rhinoptera and the second member of Euzetiinae from Mexico and from the neotropics. Keys to the subfamilies of Monocotylidae and to the species of Euzetiinae, as well as a hypothesis of phylogenetic relationships between Heterocotylinae, Decacotylinae, and Euzetiinae are provided.

A species of Serendip Brooks and Barriga, 1995, Serendip danbrooksi n. sp., is described from Mexico as a parasite of Rhinoptera steindachneri Evermann and Jenkins, 1891. The new species differs from Serendip deborahae, the type and only other known member of the genus, by having bothridia subdivided by 2 septa, 1 simple and 1 bifurcating, rather than 3 septa, 2 simple and 1 bifurcating, and by having 37–61 testes versus 64–116 testes, respectively. In general, S. danbrooksi n. sp. is smaller than S. deborahae in the number of proglottids (average 77 vs. 150, respectively) and length (maximum length 15.3 mm vs. 60.0 mm, respectively). Clarification of the details of some previously described structures is discussed.

The species composition and infection levels were determined for helminth parasites in the mole crab, Emerita rathbunae, collected from seven sandy beaches from Guerrero and Michoacan, Mexico. A total of 494 crabs were collected between August and December of 2009. The number of crabs that were examined from each beach varied from 40 in Lazaro Cardenas to 114 in El Revolcadero. The cephalothorax length varied significantly between the sampled beaches, from 32.9 ± 5.5 mm (Ixtapa) to 40.5 ±1.7 mm(Las Trancas). Four species of larval parasites were identified: 1 metacercaria (Microphallus nicolli), 1 cystacanth (Profilicollis sp.), 1 cestode (Trypanorhyncha) and 1 nematode (Proleptus sp.). Infection levels (prevalence and mean abundance) varied significantly between beaches, due to possible differences in the availability of final or intermediate hosts in beaches visited by tourist and those beaches not visited by tourists, as well as the size of individual hosts. Helminth communities, at levels of component and infracommunity, were characterized by a low number of species (3 to 4) and a high dominance by the metacercaria of M. nicolli. The body size of the hosts was positively correlated with the number of parasites and species richness of helminths, indicating that larger crabs accumulate a higher number of parasites during the lifetime, and that they harbor a higher number of species of helminth than smaller crabs.

The helminthological examination of nine individuals of Aetobatus cf. narinari (spotted eagle ray; raya pinta; arraia pintada) revealed the presence of an undescribed species of cestode of the genus Acanthobothrium. The stingrays were collected from four locations in México: Laguna Términos, south of Isla del Carmen and the marine waters north of Isla del Carmen and Champotón, in the State of Campeche, and Isla Holbox, State of Quintana Roo. The new species, nominated Acanthobothrium marquesi, is a category 3 species (i.e, the strobila is long, has more than 50 proglottids, the numerous testicles greater than 80, and has asymmetrically-lobed ovaries); at the present, the only category 3 species that has been reported in the Western Atlantic Ocean is Acanthobothrium tortum. Acanthobothrium marquesi n. sp. can be distinguished from A. tortum by length (26.1 cm vs. 10.6 cm), greater number of proglottids (1,549 vs. 656), a larger scolex (707 µm long by 872 µm wide vs. 699 µm long by 665 µm wide), larger bothridia (626 µm long by 274 µm wide vs. 563 µm long by 238 µm wide). This is the first report of a species of Acanthobothrium from the Mexican coast of the Gulf México. Resumo O exame helmintológico do trato digestivo de nove espécimes de Aetobatus cf. narinari (arraia pintada) revelou a presença de uma nova espécie de cestódeo do gênero Acanthobothrium. As arraias foram coletadas de quatro locais no México: Laguna Términos, ao sul de Isla del Carmen e nas águas marinhas ao norte de Isla del Carmen e Champotón, no estado de Campeche, e Isla Holbox, estado de Quintana Roo. A nova espécie foi denominada Acanthobothrium marquesi, pertencente a uma espécie da categoria 3 (estrobilo longo, tendo mais de 50 proglotes, numerosos testículos, superiores a 80, e ovários assimetricamente lobados). Apenas outra espécie deste gênero, Acanthobothrium tortum pertence a categoria 3, no Oceano Atlântico Ocidental. Acanthobothrium marquesi n. sp. se distingue de A. tortum por ser mais longo (26,1 cm vs. 10,6 cm), possuir maior número de proglotes (1.549 vs. 656), ter um escolex maior (707 µm de comprimento por 872 µm de largura vs. 699 µm de comprimento por 666 µm de largura), e botridias maiores (626 µm de comprimento por 274 µm de largura vs. 563 µm de comprimento por 238 µm de largura). Este é o primeiro relato de uma espécie de Acanthobothrium do Golfo do México.

A total of 141 highland swordtails, Xiphophorus malinche, were collected from 2 localities in the Pánuco river drainage (Chicayotla and Malila) from Hidalgo, México. The parasite community structure of the 2 localities was examined and compared. Five taxa of helminths were recovered: 2 digeneans, adults of Paracreptotrema sp. and metacercariae of Uvulifer sp.; an adult monogenean, Urocleidoides vaginoclastrum; an adult cestode, Bothriocephalus acheilognathi, and an adult nematode, Rhabdochona xiphophori. Among them, Ur. vaginoclastrum was the most frequent and abundant species. The remaining species were rare and found at low mean abundance. Only 2 species of helminth were found at both localities. The observed species richness, individual abundance, and diversity were low at component community and infracommunity levels. Abundance of helminths and fish standard length were correlated. Uvulifer sp. was more abundant in small fish, but Ur. vaginoclastrum showed the opposite pattern, high abundance in larger fish. Differences observed in this study can be attributed to abiotic and biotic environmental factors resulting from the geographic separation of these localities during to the orogeny of the Sierra Madre Oriental that restricted fish to isolated headwaters.

El deterioro de la calidad ambiental de las lagunas y la perdida de biodiversidad ictiológica es consecuencia de numerosas actividades antrópicas como la pesca comercial, deportes náuticos, etc. Las lagunas están formadas por una boca, una barra de arena y un cuerpo de agua (Violante-González, 2007); Laguna de Tres Palos es el complejo lagunar más grande del estado de Guerrero, localizado a 25 km. del puerto de Acapulco. La laguna posee una amplia diversidad de peces y una producción pesquera de más de 900 ton/año (Violante-González, 2007). El objetivo fue registrar la concentración de Pb y Cd en Ariopsis guatemalensis. Se realizaron 4 muestreos: en abril, junio y octubre de 2011 y en abril de 2012. Se colectaron 30 peces de A. guatemalensis en cada muestreo, se congelaron y transportaron al laboratorio, en donde se disectaron (branquias, músculo, piel, hígado y vísceras). Posteriormente, cada tipo de tejido se deshidrató en estufa hasta obtener peso seco. En el laboratorio de Química analítica de la UAEH, las muestras fueron procesadas de acuerdo al método EPA-3052. Se registró Pb y Cd en los diferentes órganos (branquias, hígado, vísceras, piel y músculo) de A. guatemalensis; las concentraciones de Pb (1.0 mg/kg) y Cd (0.5 mg/kg) sobrepasan los limites permisibles de la NOM-027-SSA1-1993. El Pb y Cd pueden biomagnificarse en el ámbito de la acuacultura (Golovanova, 2008). Por lo cual, es importante monitorear estos elementos para garantizar la calidad del pescado que proviene de ésta localidad, dado que es de importancia comercial para consumo humano.

A nivel mundial, las lagunas costeras son consideradas como ambientes de alta productividad y una elevada riqueza en biodiversidad. Están situadas a lo largo del litoral que en la mayoría de los casos tienen una comunidad permanente con el mar como es el caso de la laguna de Tampamachoco, Veracruz. Biológicamente, la zona costera y marina del Golfo de México representa una región de gran valor ecológico y económico para México ya que tiene una gran diversidad de ecosistemas marinos y recursos naturales. Los metales pesados son elementos naturales de la corteza terrestre, rocas, suelos, sedimentos, erupciones volcánicas y del agua. Existen cambios en sus concentraciones debido al uso extensivo en la industria y actividades humanas. Este estudio tuvo como objetivo el determinar si se encuentran presentes los metales pesados Ba, Cu y Hg en organismos de lebrancha (Mugil curema Valenciennes, 1836). Se muestrearon peces para el análisis cuantitativo de los metales pesados. El método que se utilizó se hizo en base a la Norma Oficial Mexicana NOM-117-SSA1-1994 mediante la técnica “Espectrometría de absorción atómica”. Se hicieron 14 muestreos del 2009 al 2010. La concentración promedio en tejidos para el músculo fue de Ba= 9.66 mg/kg, Cu= 3.33 mg/kg; en piel fue de Ba= 14.40 mg/kg, Cu= 6.28 mg/kg; en branquias fue de Ba= 43.26 mg/kg, Cu= 8.13 mg/kg; y finalmente en hígado fue de Ba= 7.57 mg/kg, Cu= 25.99 mg/kg. Las concentraciones que se hallaron en los tejidos de M. curema principalmente en las branquias son el tejido principal de recolección de los metales pesados, ya que la respiración es un factor determinante en la bioacumulación de estos contaminantes.

En México, los peces son un grupo diverso y es el taxón con la mayor cantidad de estudios parasitológicos, sin embargo aún falta conocimiento en especies de peces endémicas. Los peces actúan como hospederos definitivos, intermediarios y paraténicos de los helmintos. La estructura de las comunidades de helmintos depende de factores atribuibles al hospedero, al ambiente y al mismo parásito. El objetivo del trabajo fue describir la estructura de las comunidades de parásitos en Xiphophorus birchmanni, Pseudoxiphophorus bimaculata y Amantitlania nigrofasciata, especies en simpatría en San Pedro (Río Huazalingo) y Huiznopala (Río Atlapexco). En 2008 y 2009 se colectaron peces y se sometieron a un examen helmintológico. Los helmintos recolectados se procesaron e identificaron taxonómicamente. Se calcularon índices de diversidad. Se registraron 7 especies de helmintos: Centrocestus formosanus, Uvulifer sp., Girodactilidae sp., Urocleidoides vaginoclastrum, Rhabdochona sp., R. kidderi y Spinitectus sp. Las especies de monogéneos fueron las más abundantes y dominantes en las comunidades, especialmente en X. birchmanni. Los nemátodos fueron el grupo mejor representado. A nivel componente de comunidad, X. birchmanni presento la mayor riqueza. Las comunidades de helmintos de estos peces son pobres y altamente dominadas por monogéneos. La especificidad hospedatoria y hábitos alimenticios de los hospederos influencian la estructura de comunidad de helmintos.

Como parte de un estudio de la calidad ambiental de Lago de Tecocomulco, Hidalgo, México, fueron colectados los helmintos intestinales de 70 aves de cinco especies: Anas americana, Anas discors, Aythya valisineria, Gallinula chloropus y Fulica americana. Los intestinos de las aves fueron donados por los cazadores locales, transportadas al laboratorio y los helmintos fueron colectados, fijados en AFA y conservados en alcohol etílico (70%) hasta su tinción y montaje. Ocho especies de dos taxa de helmintos fueron encontrados: Digenea-Echinostoma revolutum, Zygocotyle lunata, Echinoparyphium recurvatum, Notocotylus pacifer, Apatemon gracilis, Pseudoapatemon sp.; y Acanthocephala-Polymorphus trochus y Pseudocorynosoma constrictum. Echinostomum revolutum tuvo la mayor prevalencia, abundancia e intensidad promedio en las 36 aves de la Familia Anatidae; una prevalencia de 40% fue encontrada en cada especie de ave de esta familia. Sin embargo, en F. americana (Rallidae), P. trochus tuvo la mayor prevalencia (58.6%), una abundancia de 2.0 y N. pacifer tuvo mayor intensidad promedio (4.3). Echinostomum revolutum y Ps. Constrictum se registran por segunda ocasión en Hidalgo; Z. lunata, N. pacifer, A. gracilis y P. trochus son nuevos registros para las aves en Hidalgo y Pseudoapatemon sp. es un nuevo registro para México. Es importante monitorear los parásitos de las aves acuáticas migratorias en Lago de Tecocomulco ya que sirven como indicadores de la calidad ambiental del lago.

Aplectana uaehi n. sp., which inhabits the small intestine of Ambystoma velasci, the Plateau Tiger Salamander, collected from Lago de Tecocomulco, Hidalgo, Mexico, is described. This new species is distinguished from all other species of Aplectana in having 3 toothlike projections in the esophagus, each tooth bearing 3 ridges. The new species most closely resembles Aplectana hylambatis. The latter species also has 3 toothlike projections, but they are covered by a thick cuticle and each has a small cuticular spike that projects into the buccal cavity (Baker, 1980), features not present in members of Aplectana uaehi n. sp. In addition, the 2 species differ in the length of the spicules of males (240–350 µm vs. 320–520 µm, respectively) and the number of postcloacal papillae (4–6 pairs vs. 10 pairs, respectively). This record represents the first report of Aplectana in a member of the Order Caudata and is the first member of the genus found as a parasite of a species endemic to Mexico that is itse...

The primary objective was to document the diversity of fishes in Reserva de la Biosfera Barranca de Metztitlan, Hidalgo, Mexico. Samples were collected from 35 localities using electrofishing, nets, and angling, and from local fishermen. A total of 7,290 specimens was collected, representing 16 species (including 4 introduced and 4 translocated). This study adds seven species to the regional fish fauna, five of which are exotic.

Neoechinorhynchus brentnickoli n. sp. is described from specimens of Dormitator latifrons (Pacific fat sleeper) collected from 3 localities along the Pacific Coast of Mexico: Tres Palos Lagoon (Guerrero State), Bahia de Chamela (Jalisco State), and Mazatlan (Sinaloa State), Mexico. Of the 3 members of the genus known from Mexican fish, the new species is more similar to Neoechinorhynchus golvani Salgado-Maldonado, 1978, than to Neoechinorhynchus roseus Salgado-Maldonado, 1978, or Neoechinorhynchus chimalapasensis Salgado-Maldonado, Caspeta-Mandujano, and Martinez-Ramirez, 2010. Neoechinorhynchus brentnickoli n. sp. can be distinguished from N. golvani in being longer and having more dimorphism between trunk length of males and females, a different number of ventral giant nuclei (2 vs. 1), smaller proboscis, shorter hooks in all 3 circles, a longer receptacle, and larger testes and cement gland. The anterior portion of the trunk wall of the new species is more delicate than that of the rest of the...

Centrorhynchus microcephalus (Bravo-Hollis, 1947) Golvan, 1956 (Acanthocephala: Centrorhynchidae) originally was described as Gordiorhynchus microcephalus Bravo-Hollis, 1947 on the basis of 8 worms collected from the small intestine of a single great-tailed grackle (Quiscalus mexicanus) from the state of Puebla, Mexico. Acquisition of 48 specimens collected from the groove-billed ani (Crotophaga sulcirostris) in Tlacotalpan, Veracruz, Mexico permitted a more complete description of the species. Nine of 10 (90%) birds examined were infected with 2–13 individuals of Centrorhynchus microcephalus with a mean intensity of 5.3. Examination of the type material of Centrorhynchus crotophagicola Schmidt and Neiland, 1966 revealed this species, described from groove-billed anis and squirrel cuckoos (Piaya cayana) from Nicaragua, to be conspecific with C. microcephalus; thus, C. crotophagicola is considered a junior synonym of C. microcephalus. Centrorhynchus microcephalus is redescribed on the basis of the...