Parasites (Monogenea) of tilapias Oreochromis niloticus and Coptodon rendalli (Cichlidae) in a river spring in Brazil.

In the present study, we examined 30 individuals of introduced African cichlids, Oreochromis niloticus and Coptodon rendalli, collected in a river spring of the Pardo River, Paranapanema River basin, southeastern Brazil. Based on morphological and molecular analyses of the partial LSU rDNA gene, we identified four species of monogeneans, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei, and Scutogyrus longicornis on the gills of O. niloticus, whereas individuals of C. rendalli were infested only with C. papernastrema. This is the first record of C. mbirizei and C. papernastrema in tilapias from Brazil. The ecological consequences of the introduction of exotic species of tilapia such as O. niloticus and C. rendalli along with their monogenean parasites in a wild environment represented by a river spring are discussed. Our new molecular data on Cichlidogyrus and Scutogyrus contribute to the investigation of the phylogenetic interrelationships of these widely distributed genera of monogeneans since their species composition is still unsettled.

Title: Parasites (Monogenea) des tilapias Oreochromis niloticus et Coptodon rendalli (Cichlidae) dans une source au Brésil. Abstract: Dans la présente étude, nous avons examiné 30 individus de cichlidés africains introduits, Oreochromis niloticus et Coptodon rendalli, collectés dans une source fluviale du fleuve Pardo, bassin du fleuve Paranapanema, dans le sud-est du Brésil. Sur la base d'analyses morphologiques et moléculaires du gène partiel de l'ADNr LSU, nous avons identifié quatre espèces de monogènes, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei et Scutogyrus longicornis sur les branchies d'O. niloticus, alors que les individus de C. rendalli étaient infestés uniquement par C. papernastrema. Il s'agit du premier signalement de C. mbirizei et C. papernastrema chez des tilapias du Brésil. Les conséquences écologiques de l'introduction d'espèces exotiques de tilapia telles que O. niloticus et C. rendalli ainsi que leurs monogènes parasites dans un environnement sauvage représenté par une source fluviale sont discutées. Nos nouvelles données moléculaires sur Cichlidogyrus et Scutogyrus contribuent à l'étude des interrelations phylogénétiques de ces genres de monogènes largement distribués puisque leur composition spécifique est encore incertaine.

A new species of Urocleidoides Mizelle & Price, 1964 from the gills of Schizodon nasutus Kner, 1858 (Characiformes, Anostomidae) in southeastern Brazil.

Based on an integrative approach, this study describes a new species of Urocleidoides infesting Schizodon nasutus in the Paranapanema River basin, Brazil. The new species can be distinguished from its congeners by specific morphological features, including the shape of the male copulatory organ and accessory piece, the ventral bar shape, and the shape and size of the hooks. Molecular analyses, particularly of the 28S rDNA gene, suggest a close relationship between the new species and Urocleidoides paradoxus. The phylogenetic and taxonomic arrangement of Urocleidoides is discussed, as the analyses of the 28S rDNA and COI mtDNA resolved the genus as non-monophyletic, with Diaphorocleidus, Rhinoxenus, and Cacatuocotyle nested within it. Additional morphological and molecular data of other congeneric species are required to investigate the phylogenetic position and classification of Urocleidoides. This study underscores the significance of using integrative approaches in understanding host-parasite associations and phylogenetic relationships, contributing to the description of the freshwater fish parasite biodiversity in South America, particularly in the Paranapanema river basin.

A new species of Cosmetocleithrum (Monogenea, Dactylogyridae) from the gills of Auchenipterichthys coracoideus (Siluriformes, Auchenipteridae) from the Peruvian Amazonia / Una nueva especie de Cosmetocleithrum (Monogenea, Dactylogyridae) de las branquias de Auchenipterichthys coracoideus (Siluriformes, Auchenipteridae) de la Amazonía peruana

Abstract In this study, a new species of Monogenoidea, Cosmetocleithrum amazonensis n. sp., parasitizing the gills of the silurid Auchenipterichthys coracoideus (Eigenmann & Allen, 1942), is documented. Cosmetocleithrum amazonensis n. sp. is distinguished from all other congeners by possessing an elongated, sclerotized, and sinuous male copulatory organ (MCO) with poorly defined spirals, a sclerotized border at the base, and the distal region supported by the accessory piece. The accessory piece is a single, robust, and non-articulated plate with the MCO. This study presents the third record of a Monogenoidea species in an Auchenipteridae (Siluriformes) host from Peru.

Resumen En este trabajo se registra una nueva especie de Monogenoidea, Cosmetocleithrum amazonensis n. sp., parasitando las branquias del silurido Auchenipterichthys coracoideus (Eigenmann & Allen, 1942). Cosmetocleithrum amazonensis n. sp. se distingue de todas las demás especies congéneres por poseer un órgano copulador masculino (OCM) tubo alargado, esclerotizado y sinuoso, con espirales poco definidos, base con borde esclerotizado y con la región distal apoyada sobre la pieza accesoria. La pieza accesoria es una placa única, robusta y no articulada con el OCM. En este estudio se presenta el tercer registro de una especie de Monogenoidea en un hospedero Auchenipteridae (Siluriformes) del Perú.

Parasites of Astyanax lacustris (Pisces, Characiformes) from Brazilian streams / Parasitas de Astyanax lacustris (Pisces, Characiformes) de riachos brasileiros

Abstract Astyanax lacustris is a small characid fish widely distributed in Brazil, with fast-growing and omnivorous feeding habits. Although the species presents economic and ecological importance, little is known about its parasitological fauna in stream environments. This study aimed to characterize the parasitic fauna of A. lacustris in two streams in the state of Paraná, Brazil. Fifty-two specimens of A. lacustris were collected, 22 from the Carolina stream (Lower Iguaçu River) and 30 from the Carreira stream (Upper Paraná River), in July and September 2018. In both streams, there was a low richness of parasites, and the structure of the parasitic community was predominantly composed of monogeneans. These findings may be associated with the gregarious behavior of the host species. Moreover, the low occurrence of endohelminths, may be associated with the fact that in streams, the energy flow is low, and depends directly on the input of allochthonous matter, which favors the formation of shelters for the establishment of macroinvertebrates, which represent important sources of food for the ichthyofauna, and may act as intermediate and paratenic hosts of parasites. These environments require further studies to support conservation measures aimed at maintaining the balance of ecological relationships in these preserved ecosystems.

Resumo Astyanax lacustris é um caracídeo de pequeno porte, amplamente distribuído no Brasil, com hábito alimentar onívoro e rápido crescimento. Embora a espécie tenha importância econômica, pouco se sabe sobre sua fauna parasitológica em ambientes de riacho. Este estudo objetivou caracterizar a fauna parasitária de A. lacustris em dois riachos do estado do Paraná. Foram coletados 52 exemplares de A. lacustris, sendo 22 no riacho Carolina (baixo rio Iguaçu) e 30 no riacho Carreira (alto rio Paraná), nos meses de julho e setembro de 2018. Em ambos os riachos, houve baixa riqueza de parasitos e a estrutura da comunidade parasitária foi caracterizada pela predominância de monogenéticos. Esses achados podem estar associados ao comportamento gregário da espécie hospedeira. Ademais, a baixa ocorrência de endohelmintos pode estar associada ao fato de que, nos riachos, o fluxo de energia é baixo e depende diretamente do aporte de matéria alóctone, que favorece a formação de abrigos para o estabelecimento de macroinvertebrados, os quais representam uma das principais fontes de alimento da ictiofauna, e podem atuar como hospedeiros intermediários e paratênicos de parasitos. Esses ambientes necessitam de mais estudos para subsidiar medidas de conservação que visem manter o equilíbrio das relações ecológicas nesses ecossistemas preservados.

Exploring Evolutionary Relationships within Neodermata Using Putative Orthologous Groups of Proteins, with Emphasis on Peptidases.

The phylogenetic relationships within Neodermata were examined based on putative orthologous groups of proteins (OGPs) from 11 species of Monogenea, Trematoda, and Cestoda. The dataset included OGPs from BUSCO and OMA. Additionally, peptidases were identified and evaluated as phylogenetic markers. Phylogenies were inferred using the maximum likelihood method. A network analysis and a hierarchical grouping analysis of the principal components (HCPC) of orthologous groups of peptidases were performed. The phylogenetic analyses showed the monopisthocotylean monogeneans as the sister-group of cestodes, and the polyopisthocotylean monogeneans as the sister-group of trematodes. However, the sister-group relationship between Monopisthocotylea and Cestoda was not statistically well supported. The network analysis and HCPC also showed a cluster formed by polyopisthocotyleans and trematodes. The present study supports the non-monophyly of Monogenea. An analysis of mutation rates indicated that secreted peptidases and inhibitors, and those with multiple copies, are under positive selection pressure, which could explain the expansion of some families such as C01, C19, I02, and S01. Whilst not definitive, our study presents another point of view in the discussion of the evolution of Neodermata, and we hope that our data drive further discussion and debate on this intriguing topic.

Morphology and molecular characterization of Polystoma goeldii n. sp. (Monogenea, Polystomatidae) parasite from the urinary bladder of Physalaemus ephippifer (Steindachner) (Anura, Leptodactylidae).

Polystomatid flatworms of amphibians are represented in the Neotropical realm by species of Mesopolystoma, Nanopolystoma, Parapseudopolystoma, Polystoma, Riojatrema and Wetapolystoma but only species of Polystoma are known from Brazil, namely Polystoma cuvieri, P. knoffi, P. lopezromani and P. travassosi. During a survey of monogeneans infecting amphibians in the north-eastern region of Pará State, the Cayenne Caecilian Typhlonectes compressicauda was found to be infected with Nanopolystoma tinsleyi and the Veined Tree Frog Trachycephalus typhonius was found to harbor Polystoma lopezromani. A yet unknown species of Polystoma was also encountered in the urinary bladder of the Steindachner's Dwarf Frog, Physalaemus ephippifer. This new species, which is the second species reported from Physalaemus spp., is described herein as Polystoma goeldii n. sp. and its life cycle is also illustrated. The new species can be distinguished from Polystoma spp. from other neotropical realm by a combination of characteristics, including hamuli morphology, outer/inner hamuli length ratio, haptor/total body length ratio, genital bulb/total body length ratio, genital spine number and COI molecular characters.

Seasonal patterns of infestation by monogenean parasites of fish and their relationship with water parameters in two rivers with different disturbance gradients in southeastern Brazil / Padrões sazonais de infestação por parasitos monogenéticos de peixes e sua relação com os parâmetros da água em dois rios com diferentes gradientes de perturbação no sudeste do Brasil

Here, we evaluate the relationships between the infestation rates of five monogenean parasites species with the dry and wet seasons, with the organic and inorganic parameters of the water of two rivers: the Jacaré-Pepira and Jacaré-Guaçú, and with the condition factors of its fish hosts: Serrasalmus maculatus and Astronotus crassipinnis, in the state of São Paulo, southeastern Brazil. Fish were collected between January and December 2017. Anacanthorus serrasalmi, Amphithecium speirocamarotum and Gussevia asota had higher abundance rates (Student's t test, p ≤ 0.05) in the wet season. Gussevia asota had its abundance negatively correlated to nitrate in the Jacaré-Pepira River and with total nitrogen and potassium in the Jacaré-Guaçú River. Regarding the fish hosts condition factors, was observed a positive correlation with the abundances of G. asota in the Jacaré-Guaçú River, and with A. serrasalmi in the Jacaré-Pepira River. In general, wet season favored an increasing in the infestation rates of the monogeneans parasites in their host species, mainly in the river considered as the most polluted, the Jacaré-Guaçú River. Of the five parasites species analyzed in this study, only Gussevia astronoti and Rhinoxenus piranhus had no interaction with seasonality, river water variables, or fish host condition factors. On the other hand, G. asota had interactions both with water parameters (nitrate and total nitrogen) and with the hosts condition factors, which reflected in the abundance and intensity rates, showing itself as a species sensitive to changes in the environment and, therefore, that can be considered as a bioindicator organism.

Aqui, nós avaliamos as relações entre as taxas de infestação de cincos espécies de parasitos monogenéticos em relação aos períodos seco e chuvoso, aos parâmetros orgânicos e inorgânicos da água de dois rios: Jacaré-Pepira e Jacaré-Guaçú, e em relação aos fatores de condição das espécies de peixes hospedeiras: Serrasalmus maculatus e Astronotus crassipinnis, no estado de São Paulo, sudeste do Brasil. Os peixes foram coletados entre os meses de janeiro a dezembro de 2017. Anacanthorus serrasalmi, Amphithecium speirocamarotum e Gussevia asota tiveram maiores taxas de abundância (teste t de Student, p ≤ 0,05) no período chuvoso. Gussevia asota teve sua abundância negativamente correlacionada com o nitrato no rio Jacaré Pepira e com o nitrogênio total e potássio no rio Jacaré-Guaçú. Em relação ao fator de condição dos peixes, foi observado uma correlação positiva com a abundância de G. asota no rio Jacaré-Guaçú e com A. serrasalmi no rio Jacaré-Pepira. No geral, o período chuvoso favoreceu um aumento nas taxas de infestação dos parasitos monogenéticos em seus peixes hospedeiros, especialmente no rio considerado como o mais poluído, o rio Jacaré-Guaçú. Das cinco espécies de parasitos analisadas no estudo, somente Gussevia astronoti e Rhinoxenus piranhus não tiveram nenhum tipo de interação com a sazonalidade, com as variáveis das águas dos rios ou com o fator de condição dos peixes hospedeiros. Por outro lado, G. asota teve interações tanto com os parâmetros da água (nitrato e nitrogênio total) quanto com os fatores de condição dos hospedeiros, que refletiram nas taxas de abundância e de infestação, mostrando que esta espécie é sensível às mudanças no ambiente e que, portanto, pode ser utilizada como um organismo bioindicador.

PERUANOCOTYLE PELAGICA N. SP. (MONOGENEA: MONOCOTYLIDAE), PARASITE OF THE PACIFIC COWNOSE RAY RHINOPTERA STEINDACHNERI EVERMANN AND JENKINS, 1891 (BATOIDEA: RHINOPTERIDAE) FROM THE SOUTHERN MEXICAN PACIFIC OCEAN.

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.

Neobenedenia melleni from reef ornamental fish species in a retailer of Southeastern Brazil and its possible role as a mechanical vector of bacterial infection.

Annually, more than 2500 ornamental fish species are traded worldwide. Forty percent of these are from marine water. Some 98% of marine species are wild-caught from their natural habitat, and the majority subsequently exported. Wild fish frequently carry pathogens, which could induce diseases after the stress of capture. Neobenedenia melleni is a platyhelminth that mainly attaches to the skin and eyes of the host. It provokes dermal inflammation, epidermal loss, skin depigmentation, reduction in the number of mucous cells, and, consequently, decreased mucus protection, and declining immunological barriers. This makes fish susceptible to secondary infections. A total of 47 wild reef fish from a retailer were examined, suspected to be infected with ectoparasites. The morphological identification revealed N. melleni as a monogenean agent. One monogenean specimen was collected from the eye of each of the 40 fish analyzed to evaluate possible bacterial secondary infections using the matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) technique. The MALDI-TOF MS identified that 59% of monogenean collected from the eyes had bacteria, including some pathogenic to fish. This led us to believe that the ectoparasite can be a possible mechanical vector of pathogenic bacteria for fish culture and maintenance. The use of praziquantel as an antiparasitic agent is also discussed.

Enterogyrus spp. (Monogenea: Ancyrocephalinae) and Aeromonas jandaei co-infection associated with high mortality following transport stress in cultured Nile tilapia.

Monogenean infection of the internal organs is extremely rare when compared to external infections. This study describes mass mortality of Nile tilapia (Oreochromis niloticus L.) originating from co-infection with Enterogyrus spp. and Aeromonas jandaei following transport stress. The first fish deaths occurred on day 1 post-transport, while cumulative mortality reached approximately 90% by day 10 post-stocking. An atypical amount of pale (whitish) faeces floating on the surface of the water as well as typical clinical signs of motile Aeromonas septicemia, were reported. Adult monogeneans and countless eggs of monogeneans were found in the stomachs and the intestines of both moribund and dead fish, respectively. Two strains of A. jandaei were isolated from the kidneys. Scanning electron microscope microphotographs of the stomach revealed the presence of numerous monogeneans penetrating deep into the gastric tissue, and diffuse lesions filled with bacilliform bacteria. Histopathological examination showed multifocal eosinophilic infiltrate, gastric gland and epithelial necrosis with sloughed necrotic debris in the lumen. This is the first report of co-infection by Enterogyrus spp. and A. jandaei in Nile tilapia and the first report of Enterogyrus coronatus, Enterogyrus foratus, and Enterogyrus malbergi parasitizing tilapia in Brazil. These findings indicate that synergic co-infection by Monogenean stomach parasites (E. coronatus, E. foratus, and E. malbergi) and A. jandaei may induce high mortalities in tilapia following transport stress.

Seeds of Cucurbita maxima and Carica papaya are effective for controlling monogeneans in the gills of Leporinus macrocephalus / Sementes de Cucurbita maxima e Carica papaya são eficazes no controle de monogenéticos das brânquias de Leporinus macrocephalus

This study was carried out to evaluate the anthelminthic efficacy of seeds of Cucurbita maxima and Carica papaya for controlling monogeneans in the gills of Leporinus macrocephalus, besides hepatosomatic and splenosomatic index and condition factor of host. The fish were fed with seeds of C. maxima or C. papaya for seven days, and these treatments did not cause any mortality among them. Jainus leporini, Urocleidoides paradoxus, Urocleidoides eremitus and Tereancistrum parvus were the monogeneans found, and their prevalence in fish fed with seeds of C. papaya was 100%, while in fish fed with C. maxima the prevalence was 42.8%. Fish fed with seeds of C. papaya showed decreased in intensity and abundance of monogeneans, while fish fed with seeds of C. maxima presented decreased in abundance. Feeding of L. macrocephalus with seeds of C. maxima or C. papaya had efficacy of 69.6 and 67.8%, respectively. The hepatosomatic index of fish fed with seeds of C. maxima or C. papaya was not affected by the treatments. However, the splenosomatic index and condition factor of fish fed with C. maxima seeds decreased. Seeds of C. maxima and C. papaya may be used for controlling monogeneans of L. macrocephalus in fish farming.(AU)

Este estudo avaliou a eficácia antihelmíntica de sementes de Cucurbita maxima e Carica papaya no controle de monogenéticos das brânquias de Leporinus macrocephalus, além do índice hepatossomático e esplenossomático e do fator de condição do hospedeiro. Os peixes foram alimentados com sementes de C. maxima ou C. papaya durante sete dias, e os tratamentos não causaram mortalidade. Monogenéticos Jainus leporini, Urocleidoides paradoxus, Urocleidoides eremitus e Tereancistrum parvus tiveram prevalência de 100% nos peixes alimentados com sementes de C. papaya, enquanto nos peixes alimentados com C. maxima a prevalência foi de 42,8%. Os peixes alimentados com sementes de C. papaya apresentaram diminuição na intensidade média e abundância média de monogenéticos, enquanto os peixes alimentados com sementes de C. maxima apresentaram uma diminuição na abundância média. A alimentação de L. macrocephalus com sementes de C. maxima ou C. papaya teve eficácia de 69,6 e 67,8%, respectivamente. O índice hepatossomático dos peixes alimentados com sementes de C. maxima ou C. papaya não foi afetada pelos tratamentos. No entanto, o índice esplenossomático e o fator de condição dos peixes alimentados com sementes de C. maxima diminuíram. Sementes de C. maxima e C. papaya podem ser usadas no controle de monogenéticos das brânquias de L. macrocephalus em piscicultura.(AU)

Monogeneans of Colossoma macropomum (Cuvier, 1818) (Characiformes: Serrasalmidae) farmed in the state of Acre, Amazon (Brazil) / Monogeneas de Colossoma macropomum (Cuvier, 1818) (Characiformes: Serrasalmidae) cultivados no estado do Acre, Amazônia (Brasil)

Parasitism of Colossoma macropomum is of particular concern because it is the most commonly farmed native fish species in Brazil. Nevertheless, the parasitic fauna of this species in the state of Acre has been little studied. For this reason, an evaluation was made of the parasitic fauna of farmed C. macropomum in the municipality of Rio Branco in southwestern Amazon. Four monogenean species were found in the 122 fish examined: Anacanthorus spathulatus, Linguadactyloides brinkmanni, Notozothecium janauachensis and Mymarothecium boegeri. The most prevalent species was A. spathulatus (50%), followed by N. janauachensis (44.3%), M. boegeri (20.5%) and L. brinkmanni (9.0%). These results are the first data on the ecological indices of monogeneans in tambaqui in the state of Acre and will be useful for future comparisons of the influence of environmental factors on the parasite-host relationship.(AU)

O parasitismo em Colossoma macropomum é particularmente preocupante porque é a espécie de peixe nativa mais cultivada no Brasil, no entanto a fauna parasitária dessa espécie no estado do Acre é pouco estudada. Assim, foi avaliada a fauna parasitária de C. macropomum cultivado no município de Rio Branco, no sudoeste da Amazônia. Foram encontradas quatro espécies de monogeneas nos 122 peixes examinados: Anacanthorus spathulatus, Linguadactyloides brinkmanni, Notozothecium janauachensis e Mymarothecium boegeri. As espécies mais prevalentes foram A. spathulatus (50%), seguido de N. janauachensis (44,3%), M. boegeri (20,5%) e L. brinkmanni (9,0%). Esses resultados são os primeiros dados sobre os índices ecológicos dos parasitos monogenéticos em tambaqui no estado do Acre e serão úteis para futuras comparações da influência dos fatores ambientais na relação parasito-hospedeiro.(AU)

Morphological and molecular characterization of Ameloblastella pirarara sp. n. (Monogenoidea: Dactylogyridae) parasitizing the large Amazonian catfish Phractocephalus hemioliopterus.

In this study, integrative taxonomy is applied to describe a new dactylogyrid species, Ameloblastella pirarara sp. n. from the gills of Phractocephalus hemioliopterus, a commercially and ecologically important Amazonian catfish. Ameloblastella pirarara sp. n. can be distinguished from its congeners mainly by the morphology of the male copulatory organ (MCO), accessory piece, and anchors. The new species most resembles Ameloblastella unapi, from the Peruvian Amazon, but differs from it by the number of MCO rings, morphology of the vaginal canal and sclerotized structures of the haptor. Phylogenetic analyses based on sequences of the partial 28S rDNA (D1-D2 domains) gene placed the new species in a well-supported subclade of Ameloblastella spp. parasites of Neotropical siluriform fish, as a sister taxon to Ameloblastella unapioides. Thus, the new species described herein expands our knowledge of the diversity of monogenoid parasites from Amazonian freshwater fish.

A new species of Neoheterobothrium Price, 1943 (Monogenea, Diclidophoridae) from Syacium papillosum (Linnaeus) (Pleuronectiformes, Paralichthyidae) in the Yucatan Shelf, with notes on the validity of the subfamilies in the Diclidophoridae.

Neoheterobothrium papillosum n. sp. (Monogenea: Diclidophoridae) is described based on specimens collected from the gills of the dusky flounder Syacium papillosum (Linnaeus) (Paralichthyidae) in the Yucatan Shelf. The new species can be differentiated from other congeneric species by the following characteristics: (1) number of hooks in the genital atrium (8 hooks), (2) number of testes (20-34), (3) pharynx size, (4) peduncle length, and (5) egg size. Neoheterobothrium papillosum n. sp. resembles Neoheterobothrium syacii; however, detailed morphological analysis allowed for their separation into two different species. Sequences of the nuclear ribosomal DNA partial 28S and ITS1 were obtained and compared with available sequences of other species and genera of the family Diclidophoridae from GenBank. A phylogenetic analysis was conducted, including 33 sequences, 18 of which represented 17 species and 11 genera of the family Diclidophoridae. The phylogenetic tree showed that Diclidophoridae is a monophyletic family and species of Diclidophora were grouped as the sister group of Neoheterobothrium papillosum n. sp. Our phylogenetic analyses were consistent with Mamaev's hypothesis, who divided Diclidophoridae into Diclidophorinae and Choricotylinae and concluded that Neoheterobothrium was a genus belonging to Diclidophorinae.

Description of a new species of Engraulicola George 1960 (Monogenea: Gastrocotylidae) parasitizing gills of Chloroscombrus chrysurus (Carangidae) from Veracruz, southern Gulf of Mexico / Descrição de uma nova espécie de Engraulicola George 1960 (Monogenea: Gastrocotylidae) parasito de brânquias de Chloroscombrus chrysurus (Carangidae) de Veracruz, Sul do Golfo do México

Engraulicola lamothei n. sp. (Monogenea: Gastrocotylidae) is described from the gills of Chloroscombrus chrysurus (Teleostei: Carangidae) from Veracruz, southern Gulf of Mexico. This monogenean is 1110-1670 (1328) µm long and 260-550 (363) µm wide. The haptor is asymmetrical, the long side has several clamps (35-42), and the short side has a single clamp; the posterior end has a small lappet armed with two dissimilar pairs of hooks. Male and female genital pores open near the anterior body end; the male genital pore is ventral, armed with a corona of 12 spines; the female pore is dorsal and unarmed. The new species differs from Engraulicola forcipopenis George, 1960 and from Engraulicola micropharyngella Unnithan, 1967 by lacking a pair of pointed forceps-like spines at the end of the penis amid the corona spines, and from Engraulicola thrissocles Tripathi, 1959 by the number of clamps on both sides, the number the hook pairs on the terminal lappet and the testis number. This is the first record of the genus Engaulicola George, 1960 on the Atlantic West Coast.(AU)

Engraulicola lamothei n. sp. (Monogenea: Gastrocotylidae) é descrito a partir das brânquias de Chloroscombrus chrysurus (Teleostei: Carangidae) de Veracruz, Sul do Golfo do México. Este monogêneo tem 1110-1670 (1328) µm de comprimento e 260-550 (363) µm de largura. O haptor é assimétrico, o lado longo tem vários grampos (35-42), e o lado curto tem um único grampo, e a extremidade posterior tem um pequeno lappet armado com dois pares de ganchos diferentes. Os poros genitais masculino e feminino são abertos perto da extremidade anterior do corpo; o poro genital masculino é ventral, armado com uma coroa de 12 espinhos; o poro feminino é dorsal e desarmado. A nova espécie difere de Engraulicola forcipopenis George, 1960 e de Engraulicola micropharyngella Unnithan, 1967, pela ausência de um par de fórceps pontiagudos como espinhos localizados na extremidade do pênis, em meio aos espinhos da coroa; e de Engraulicola thrissocles Tripathi, 1959, pelo número de pinças em ambos os lados, pelo número de pares de ganchos no lappet terminal, e pelo número de testículos. Este é o primeiro registro do gênero Engaulicola George, 1960 para a costa oeste do Atlântico.(AU)

Description of a new species of Engraulicola George 1960 (Monogenea: Gastrocotylidae) parasitizing gills of Chloroscombrus chrysurus (Carangidae) from Veracruz, southern Gulf of Mexico / Descrição de uma nova espécie de Engraulicola George 1960 (Monogenea: Gastrocotylidae) parasito de brânquias de Chloroscombrus chrysurus (Carangidae) de Veracruz, Sul do Golfo do México

Abstract Engraulicola lamothei n. sp. (Monogenea: Gastrocotylidae) is described from the gills of Chloroscombrus chrysurus (Teleostei: Carangidae) from Veracruz, southern Gulf of Mexico. This monogenean is 1110-1670 (1328) µm long and 260-550 (363) µm wide. The haptor is asymmetrical, the long side has several clamps (35-42), and the short side has a single clamp; the posterior end has a small lappet armed with two dissimilar pairs of hooks. Male and female genital pores open near the anterior body end; the male genital pore is ventral, armed with a corona of 12 spines; the female pore is dorsal and unarmed. The new species differs from Engraulicola forcipopenis George, 1960 and from Engraulicola micropharyngella Unnithan, 1967 by lacking a pair of pointed forceps-like spines at the end of the penis amid the corona spines, and from Engraulicola thrissocles Tripathi, 1959 by the number of clamps on both sides, the number the hook pairs on the terminal lappet and the testis number. This is the first record of the genus Engaulicola George, 1960 on the Atlantic West Coast.

Resumo Engraulicola lamothei n. sp. (Monogenea: Gastrocotylidae) é descrito a partir das brânquias de Chloroscombrus chrysurus (Teleostei: Carangidae) de Veracruz, Sul do Golfo do México. Este monogêneo tem 1110-1670 (1328) µm de comprimento e 260-550 (363) µm de largura. O "haptor" é assimétrico, o lado longo tem vários grampos (35-42), e o lado curto tem um único grampo, e a extremidade posterior tem um pequeno "lappet" armado com dois pares de ganchos diferentes. Os poros genitais masculino e feminino são abertos perto da extremidade anterior do corpo; o poro genital masculino é ventral, armado com uma coroa de 12 espinhos; o poro feminino é dorsal e desarmado. A nova espécie difere de Engraulicola forcipopenis George, 1960 e de Engraulicola micropharyngella Unnithan, 1967, pela ausência de um par de fórceps pontiagudos como espinhos localizados na extremidade do pênis, em meio aos espinhos da coroa; e de Engraulicola thrissocles Tripathi, 1959, pelo número de pinças em ambos os lados, pelo número de pares de ganchos no "lappet" terminal, e pelo número de testículos. Este é o primeiro registro do gênero Engaulicola George, 1960 para a costa oeste do Atlântico.

Eye to eye: classification of conjunctival sac polystomes (Monogenea: Polystomatidae) revisited with the description of three new genera Apaloneotrema n. g., Aussietrema n. g. and Fornixtrema n. g.

Polystomes (Monogenea: Polystomatidae) of freshwater turtles are currently represented by five genera, namely Neopolystoma, Polystomoides, Polystomoidella, Uropolystomoides and Uteropolystomoides. These parasites can infect the urinary, oral and/or the conjunctival sac systems of their hosts, showing strict site specificity. A recent phylogenetic study showed that the two most diverse genera within chelonian polystomes, i.e. Neopolystoma and Polystomoides, are not monophyletic. Furthermore, polystomes infecting the conjunctival sacs of their host, except for one species, formed a robust lineage. A fusiform egg shape has been reported for conjunctival sac polystomes and it was assumed that this characteristic could be a good character for the systematics of polystomes. Our objective in the present work was, therefore, to study more in depth the morphology of polystomes collected from the conjunctival sacs of chelonians to find characters defining a putative new genus. To achieve this objective, more specimens were collected in 2018 and 2019 from turtles sampled in North Carolina and Florida (USA) to extend taxon sampling for the phylogenetic analysis. Morphological characters of relevant polystome specimens were re-examined from several collections from Asia, Australia, Europe, South Africa, South America and North America. Based on a Bayesian tree inferred from the analysis of four concatenated genes, namely 12S, 18S, 28S and COI, polystomes found in the conjunctival sacs were grouped in three distinct lineages, the first one including a single species infecting an Australian pleurodire turtle; the second one including eleven species infecting cryptodire turtles of South America, North America and Asia; and the last one including a single species infecting a softshell cryptodire turtle of North America. Based on observations of live specimens by Dr. Sylvie Pichelin and our morphological analysis, the conjunctival sac polystomes from Australian turtles are small, cannot extend their body significantly, have a spherical ovary and egg, have a large genital bulb and possess latero-ventral vaginae at the level of the testis. Based on observations of live specimens and morphological analysis of whole mounted specimens, polystomes of the second lineage share the following morphological characteristics: the ability to stretch out and double their length, a long oval ovary, a separate egg-cell-maturation-chamber, fusiform to diamond-shaped eggs with acute tips, small genital bulb and vaginae peripheral on the side of the body at the level of the testis. The polystome species of the third lineage occupies a basal position, has the ability to stretch out and possess an elongated ovary, a large fusiform egg with rounded tips, a small genital bulb and small latero-ventral vaginae at the level of the ovary. These three distinct conjunctival sac polystome lineages are herein described as separate new genera, Aussietrema, Fornixtrema and Apaloneotrema, respectively.

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).

A new species of Heterocotyle (Monogenea: Monocotylidae), a gill parasite of the diamond stingray Hypanus dipterurus (Myliobatiformes: Dasyatidae) from the Peruvian coastal zone.

INTRODUCTION: A new monogenean, Heterocotyle margaritae n. sp. (Monocotylidae: Heterocotylinae), is described based on specimens collected from the gills of the diamond stingray, Hypanus dipterurus (Jordan & Gilbert, 1880) (Myliobatiformes: Dasyatidae) captured off the South Pacific coast, Lima Region, Peru. MATERIALS AND METHODS: Monogeneans were fixed in hot 4% formalin, observed and measured as permanent mounts stained with Gomori's trichrome, and mounted in Canada balsam. Drawings were made with the aid of a drawing tube. RESULTS: The new species is distinguished from all congeners mainly by having a funnel-shaped male copulatory organ, spatulate distally with lateral folds and by its club-shaped accessory piece. The most similar congener, H. americana Hargis, 1955, resemble H. margaritae n. sp. regarding the general structure of the male copulatory organ (funnel-shaped with an accessory piece). However, besides other features, the new species differ from H. americana by having an accessory piece without a dorsal button (vs an accessory piece with a dorsal button in H. americana). CONCLUSIONS: This is the first report of a member of Heterocotyle Scott, 1904 in the Southeastern Pacific Ocean. The present finding brings to 20 the number of known species of Heterocotyle, and represents the fifth described monogenean species from Hypanus dipterurus.

Narcinecotyle longifilamentus n. gen., n. sp. (Monogenea: Hexabothriidae), gill parasite of the numbfish Narcine entemedor (Torpediniformes: Narcinidae) from the Mexican Pacific coast.

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.