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Spiral valves from specimens of the giant electric ray Narcine entemedor Jordan & Starks, 1895 were examined in search of tapeworms at 2 localities of the Mexican tropical Pacific Ocean. Acanthobothrium oceguerai n. sp. is described herein based on material from Ventanilla, Oaxaca and from Acapulco Bay, Guerrero. The new species is a category 6 species, distinguished by being apolytic, retaining proglottids on the strobila until they are gravid, having strobila of 166-322 proglottids, having a small scolex and very long bothridia relative to the scolex, and having abaxial prongs that are short and thin in comparison to the axial prongs, which are longer and more robust. Acanthobothrium oceguerai n. sp. can be differentiated from other members of category 6 by the hooks, which are shorter, more robust, and smaller than those of the other members of this category. The phylogenetic analysis based on the 28S rRNA locus placed Acanthobothrium oceguerai n. sp. as sister to an unidentified species of larval Acanthobothrium from Philadelphia, Pennsylvania. In addition, sequences of the mitochondrial cytochrome oxidase subunit I gene and nuclear 18S rDNA were generated to provide support for future taxon sampling. Acanthobothrium oceguerai n. sp. is the fifth species of cestode reported from N. entemedor in the tropical eastern Pacific., (© American Society of Parasitologists 2024.)

In the Reserva Ecológica del Pedregal of San Ángel, located in the south of Mexico City, Mexico, free-roaming dogs and cats coexist with 148 bird, 33 of mammal, 23 of reptile and seven amphibian species, that represent a remnant of the original fauna of the Mexican Plateau. The negative impact that dogs and cats have on local fauna is unobjectionable, however, the role that these introduced vertebrates play as potential transmitters of infectious diseases for native fauna and humans, is much less understood. Information about parasitic infections in native and introduced animals in this location is scarce. In order to ameliorate this lack of information, the objective of this study is to characterize the helminth fauna of the free-ranging dogs and cats of the ecological reserve. Between 2018 and 2023, 36 Felis silvestris catus and 7 Canis lupus familiaris were studied from the helminthological perspective. Endoparasites were obtained from the digestive tract and were identified to the species level using morphological and molecular evidence. Hosts were parasitized by eight species of helminths: in cats the cestodes Hydatigera taeniaeformis, Mesocestoides sp., Taenia rileyi and the nematode Toxocara cati were recorded, while in dogs, the cestode Taenia pisiformis and the nematodes Ancylostoma caninum, and Uncinaria stenocephala were found. The only species shared between cats and dogs was the cestode Dipylidium caninum. These free-ranging animals act as definitive hosts of 5 species known to have zoonotic potential; their presence in the area may generate a public and animal health problem if programs of dog and cat population control are not continued., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Camacho-Giles et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Species of Haemogregarina are blood parasites known to parasitise vertebrate hosts, including fishes (Haemogregarina sensu lato) and freshwater turtles (Haemogregarina sensu stricto). Their vectors, include gnathiid isopods and leeches, respectively. In turtles, Haemogregarina balli has the best-characterized life cycle in the genus. However, no studies in Brazil have suggested a possible vector for any species of Haemogregarina from freshwater turtles. Therefore, in the present study, we provide insights into a leech vector based on specimens found feeding on two species of freshwater turtles, Podocnemis unifilis and Podocnemis expansa, using morphological and molecular data. In 2017 and 2019, freshwater turtles were collected in Goiás State, Brazil. Hosts were inspected for ectoparasites and leeches were collected from two specimens of P. expansa and nine specimens of P. unifilis. Leeches were subsequently identified as members of the genus Unoculubranchiobdella. Leech histological slides revealed haemogregarine-like structures, similar to post-sporogonic merogony, found near the gills and within the posterior sucker. Molecular analysis of the haemeogregarines resulted in the identification of three species of Haemogregarina: Haemogregarina embaubali, Haemogregarina goianensis, and Haemogregarina brasiliana. Therefore, our findings, based on morphology and DNA data suggest leeches of the genus Unoculubranchiondella as vectors for at least three species of Haemogregarina from Brazilian turtles., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The genus Myzobdella groups five species of leeches parasites of fishes mainly of freshwater but with tolerance to brackish waters. Native distribution of these species includes the New World from North to South America. Myzobdella lugubris Leidy, 1851, the type species of the genus, was briefly described based on specimens from the USA, but subsequently their morphology, known distribution and host range were expanded; however, less is known about the other four species of the genus. As part of a survey focusing on characterizing the diversity of leeches from Mexico, specimens of Myzobdella patzcuarensis (Caballero, 1940), from the type locality of the species were included for the first time in a phylogenetic study. In addition, specimens assigned to Myzobdella from the southeast of Mexico as well as from Nicaragua, were also included. In the resulting phylogenetic tree, our newly generated sequences were found nested in the same clade that M. lugubris; with unresolved relationships and relatively low genetic divergence, suggesting conspecificity. In addition, the internal morphology of the specimens of Myzobdella from Mexico is consistent with the description of M. lugubris. Our morphological examination reveals high degrees of variability in the external pigmentation of the specimens. Based on our results we formally synonymize M. patzcuarensis under M. lugubris., (© 2024. The Author(s).)

Leech specimens of the genus Pontobdella (Hirudinida: Piscicolidae) were found off the coast of the state of Oaxaca (Pacific) as well as in Veracruz and Tabasco (Gulf of Mexico), Mexico. Based on the specimens collected in Oaxaca, a redescription of Pontobdella californiana is provided, with emphasis on the differences in the reproductive organs with the original description of the species. In addition, leech cocoons assigned to P. californiana were found attached to items hauled by gillnets and studied using scanning electron microscopy and molecular approaches. Samples of Pontobdella macrothela were found in both Pacific and Atlantic oceans, representing new geographic records. The phylogenetic position of P. californiana is investigated for the first time, and with the addition of Mexican samples of both species, the phylogenetic relationships within Pontobdella are reinvestigated. Parsimony and maximum-likelihood phylogenetic analysis were based on mitochondrial (cytochrome oxidase subunit I [COI] and 12S rRNA) and nuclear (18S rRNA and 28S rRNA) DNA sequences. Based on our results, we confirm the monophyly of Pontobdella and the pantropical distribution of P. macrothela with a new record in the Tropical Eastern Pacific., (© American Society of Parasitologists 2024.)

Peruanocotyle pelagica n. sp. is described based on specimens collected from the wall of the pharyngeal cavity of the Pacific cownose ray Rhinoptera steindachneri offshore Oaxaca and Guerrero, Mexico. The new species is distinguished from Peruanocotyle chisholmae by its anchors, which include a slender guard that curves towards the tip of the blade and which lack an accessory piece, morphological differences of the seminal vesicle, the lack of a male copulatory organ accessory piece and a greater number of spines, and an unsclerotized vagina. Molecular data of Peruanocotyle pelagica were generated to place the phylogenetic position of the genus within Monocotylidae., (© American Society of Parasitologists 2022.)

A new genus and species of Hexabothriidae Price, 1942 is described from specimens infecting the gill of the numbfish Narcine entemedor Jordan and Starks from the Pacific coast of Mexico. In addition to the new taxon described here, species of 8 genera also display symmetrical haptors and have eggs with two polar filaments. However, they differ in the combination of the following features: distal portion of the male copulatory organ tubular, unarmed and proximally dilated confining an internal coiled duct, as well as dorsal origin of haptoral appendix. Based on molecular data derived from 3 loci, the mitochondrial Cytochrome C oxidase subunit 1 as well as the nuclear ribosomal 18S and 28S, the new species was found nested within Hexabothriidae together with the other 4 genera with representatives in GenBank. This is the first species of Hexabothriidae reported from a species of Narcinidae., (Copyright © 2020 Elsevier B.V. All rights reserved.)