Morphological and molecular characterization of three new species of Gyrodactylus (Monogenea: Gyrodactylidae) infecting Sicydium salvini (Teleostei: Gobiidae) in Mexican rivers draining into the Pacific Ocean.

The genus Gyrodactylus von Nordmann, 1832 is one of the most diverse within the class Monogenea; it contains mainly parasites of freshwater and marine teleost fishes. Around 40 species of Gyrodactylus have been described from gobiid fishes; mainly in Europe, as only two species are known from the Americas. In this study, we describe three new gyrodactylids from the body surface and fins of the goby Sicydium salvini (Gobiidae, Sycydiinae), which has a wide distribution on the Pacific coast, from Mexico to Panama. We describe Gyrodactylus oaxacae n. sp., G. atoyacensis n. sp. and G. salvini n. sp. collected from rivers draining to the eastern Pacific in the state of Oaxaca, Mexico. Morphologically, G. atoyacensis n. sp. and G. salvini n. sp. are very similar, and both are easily differentiated from G. oaxacae n. sp. Phylogenetic hypotheses based on sequences of the Internal Transcribed Spacers (ITS1-5.8S-ITS2 rDNA) and the D2 + D3 domains of the large ribosomal subunit (28S rDNA) support the erection of the three new taxa; and suggest that G. atoyacensis n. sp. and G. salvini n. sp. are sister species. These gyrodactylids are the first monogeneans described from gobies of the genus Sicydium in Mexico.

Morpho-molecular characterization of Gyrodactylus parasites of farmed tilapia and their spillover to native fishes in Mexico.

Translocation of fishes for aquaculture has resulted in the co-introduction of some of their parasites. African cichlid fishes, generically called "tilapias" have been introduced worldwide, along with their monogenean parasites. In a nation-wide survey, we characterised monogeneans of the genus Gyrodactylus infecting farmed "tilapia" throughout Mexico. We also collected native fishes around farms, to look for potential parasite spillover from cultured fishes. Monogeneans were identified taxonomically using morphological and molecular characters. Originally African, pathogenic Gyrodactylus cichlidarum was recorded in every farm surveyed, infecting different "tilapia" varieties, as well as three native cichlid fish species. Previously, we had shown that G. cichlidarum also infects native, non-cichlid fishes in Mexico. We also recorded that Gyrodactylus yacatli is widely distributed in Mexico, infecting cultured "tilapia" and native fishes; and present data indicating that this is a further translocated African parasite. A third, unidentified gyrodactylid infected farmed and native fishes in Chiapas, southern Mexico; we describe the new species as Gyrodactylus shinni n. sp., and provide evidence that this is a third monogenean translocated with African fish. The wide distribution of exotic parasites co-introduced with "tilapia" and their spillover to native fishes may have an important impact on the ichthyofauna in Mexico, one the world's megadiverse countries.

Species delimitation of Gyrodactylus (Monogenea: Gyrodactylidae) infecting the southernmost cyprinids (Actinopterygii: Cyprinidae) in the New World.

The genus Gyrodactylus von Nordmann, 1832 represents one of the most diverse and widespread taxa within Monogenea, with approximately 500 species described worldwide. Thirty-three species of Gyrodactylus have been recorded in Mexico, and in the last two decades, at least 26 new species have been described mainly from freshwater fish families such as poeciliids, goodeids, profundulids, characids, and cichlids. In this study, we describe two new species of Gyrodactylus infecting freshwater cyprinids based on morphological and molecular characteristics. Gyrodactylus ticuchi n. sp. and Gyrodactylus tobala n. sp. were recovered from Notropis moralesi de Buen and N. imeldae Cortés, respectively, captured in five localities from the State of Oaxaca, Mexico. The new species differ slightly from their congeners in the morphology of the haptoral hard parts and the male copulatory organ. Sequences of the Internal Transcribed Spacers rDNA (ITS1-5.8S-ITS2), cytochrome oxidase subunit I (cox1), and the D2 + D3 domains of the large subunit (28S rDNA) were obtained from multiple specimens and analyzed using Maximum Likelihood (ML) and Bayesian Inference (BI). Phylogenetic hypotheses using ITS rDNA, cox1, and 28S rDNA genes recovered two new species of Gyrodactylus from N. moralesi and N. imeldae; we briefly discuss their phylogenetic relationship with other congeners. These gyrodactylids represent the first species described in species of Notropis from southern Mexico, the cyprinids exhibiting the southernmost distribution in the New World.

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.

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.

New Species of Gyrodactylus von Nordmann, 1832 from Native Fish from Chiapas, Mexico, Studied by Morphology and Molecular Analyses.

BACKGROUND: Three new species of Gyrodactylus von Nordmann, 1832 are described from Poeciliopsis hnilickai and Tlaloc labialis (syn. Profundulus candalarius and Profundulus labialis) from the state of Chiapas, Mexico. Gyrodactylus chiapaneco n. sp. is described from T. labialis. Gyrodactylus guatopotei n. sp. was found to infect P. hnilickai. Gyrodactylus tlaloci n. sp. is described from T. labialis. The new species were characterised morphologically (haptoral hooks) and molecularly (sequences of the Internal Transcribed Spacer region (ITS1-5.8S-ITS2) of rDNA). PURPOSE: During a survey in March 2017 in the state of Chiapas, individuals of Tlaloc labialis were collected by electrofishing from Arroyo Ojo de Agua and from Río Hondo, Ixtapa, Río Las Lajas and Poeciliopsis hnilickai from Río Hondo, Ixtapa and Río Cacao. Three new species of Gyrodactylus were found and are described herein based on morphological and genetic analysis. METHODS: Attachment hooks were excised and partially digested with a proteolytic solution to remove tissue enclosing the haptoral armature. Measurements and pictures of the haptoral hard structures were taken and were compared with other Gyrodactylus species found on poeciliids and profundulids. The bodies from which haptoral hook were removed were stored individually in 95% ethanol at - 20 °C for molecular analyses. Sequences of the Internal Transcribed Spacer region of rDNA were obtained for each species and were compared with 26 Gyrodactylus spp. The genetic divergence among species of Gyrodactylus was estimated using uncorrected "p" distances with the program MEGA. RESULTS: The haptoral hook of Gyrodactylus chiapaneco n. sp. are similar to G. poeciliae from Venezuela; those from Gyrodactylus guatopotei n. sp. resemble the sclerites of G. turnbulli from Singapore and G. pictae from Trinidad, and the haptoral hooks of Gyrodactylus tlaloci n. sp. are comparable to those of G. pseudobullatarudis and G. zapoteco from Mexico; most of these parasites were described from poeciliid fishes, except G. zapoteco which was recently described from Profundulus oxacae from Oxaca, Mexico. The sequences of the three new species were aligned with sequences of 26 other Gyrodactylus spp. Maximum likelihood and Bayesian inference analyses indicated that the three new taxa are members with well-supported lineages-the new taxa are the first species of Gyrodactylus to be described from Poeciliopsis hnilickai and Tlaloc labialis from Chiapas. CONCLUSION: Gyrodactylus chiapaneco n. sp., Gyrodactylus guatopotei n. sp. and Gyrodactylus tlaloci n. sp. are described based on morphological and molecular analyses. Two of the three new species of Gyrodactylus described here, and both roughly fall morphologically and molecularly into the group of parasites harbouring slender marginal hooks: G. chiapaneco n. sp. and G. tlaloci n. sp. both possess marginal sclerites with slim shafts and group phylogenetically with other gyrodactylids of similar marginal hook morphology. Gyrodactylus guatopotei n. sp. groups with gyrodactylids possessing marginal hooks with quite elongated shafts, most of which have been found infecting poeciliids in the Antilles (e.g. G. pictae and G. turnbulli). Poeciliid, profundulid and goodeid fishes are morphologically and ecologically similar and nowadays live in sympatry or close geographical distance in Mesoamerica.

Three new species of Gyrodactylus von Nordmann, 1832 described from Goodea atripinnis (Pisces: Goodeidae), an endemic freshwater fish from the central highlands of Mexico.

Goodea atripinnis Jordan, 1880 has a broad range of habitats and is the most widespread species of the endemic goodeid fishes, which inhabit the central highlands of Mexico. This species is known to be host to a high diversity of helminth parasites from which only three belong to the genus Gyrodactylus von Nordmann, 1832: G. lamothei Mendoza-Palmero, Sereno-Uribe et Salgado-Maldonado, 2009, G. mexicanus Mendoza-Palmero, Sereno-Uribe et Salgado-Maldonado, 2009, and G. tomahuac Rubio-Godoy, Razo-Mendivil, García-Vásquez, Freeman, Shinn et Paladini, 2016. Here, we describe three new species of Gyrodactylus collected from G. atripinnis, which were characterised morphologically (sclerites of the attachment apparatus) and molecularly (sequences of the internal transcribed spacer region of the rDNA): Gyrodactylus iunuri n. sp., Gyrodactylus katamba n. sp. and Gyrodactylus tepari n. sp. These new species were collected in three different states in the Mexican Highlands: Guanajuato, Jalisco and Querétaro. Both morphological and molecular data support the hypothesis that two distinct groups of gyrodactylids infect goodeid fishes: G. iunuri n. sp., G. tepari n. sp. and G. tomahuac possess robust hamuli and are closely related phylogenetically; while G. katamba n. sp. resembles G. lamothei in having slender hamuli with accessory sclerites adjacent to the hamuli root, and apparently shares a common ancestor with gyrodactylids infecting poeciliid fishes. New locality records of G. tomahuac are presented. The addition of the three new species of Gyrodactylus as parasites of G. atripinnis makes monogeneans the second most abundant parasite group known to infect this host.