Taxonomic Status of Diplectanum robustitubum Wu & Li, 2003 (Monogenoidea: Diplectanidae) from the Purple-Spotted Bigeye Priacanthus tayenus (Priacanthidae) and the Description of Platycephalotrema parile n. sp. (Monogenoidea: Dactylogyridae) from the Bartail Flathead Platycephalus indicus (Platycephalidae), in the Arabian Gulf.

Purple-spotted bigeyes Priacanthus tayenus Richardson (Priacanthidae) and bartail flathead Platycephalus indicus (Linnaeus) (Platycephalidae) were collected from the Arabian Gulf and examined for species of Monogenoidea (Polyonchoinea) from February to December 2020. Diplectanum robustitubum Wu & Li, 2003 and an undescribed species of Platycephalotrema Kritsky & Nitta, 2019 were recovered from the gill lamellae of these hosts, respectively. Diplectanum robustitubum from Iraq was redescribed and transferred to Oliveriplectanum Domingues & Boeger, 2008 (Diplectanidae) as Oliveriplectanum robustitubum (Wu & Li, 2003) n. comb. Platycephalotrema parile n. sp. (Dactylogyridae) from Iraq and Kuwait was described and differentiated from the similar species, Haliotrema indicum Tripathi, 1959, Platycephalotrema ogawai Kritsky & Nitta, 2019, and Platycephalotrema platycephali (Yin & Sproston, 1948) Kritsky & Nitta, 2019, based primarily on the comparative morphologies of the vaginal sclerites. Haliotrema indicum was transferred to Platycephalotrema as Platycephalotrema indicum (Tripathi, 1959) n. comb. and Haliotrema swatowense Yao, Wang, Xia, & Chen, 1998 was considered a junior subjective synonym of P. indicum. The finding of O. robustitubum in the Arabian Gulf represents a new geographic record for the species. BACKGROUND: The present paper represents the third installment concerning the monogenoids collected during surveys to explore their diversity on the marine and freshwater fishes of Iraq. Previous installments on the monogenoids emanating from the surveys included the dactylogyrid and gyrodactylid species parasitizing mugilid fishes. PURPOSE: The purpose of this paper is to further document the diversity of monogenoids infecting the fishes of Iraq. METHODS: Marine fishes were necropsied for parasites, and standard procedures for collecting, mounting, drawing, and measuring of monogenoids were employed. RESULTS: Oliveriplectanum robustitubum n. comb. (Diplectanidae) and Platycephalotrema parile n. sp. (Dactylogyridae) were collected. The occurrence of O. robustitubum in the Arabian Gulf represented a new locality record for the species. CONCLUSION: The recorded presence of O. robustitubum and P. parile n. sp. suggests that the diversity of monogenoids in Iraq is under estimated in the literature.

Evolutionary morphology of haptoral anchors in monogenoids (Dactylogyridae) of marine catfish (Siluriformes: Ariidae) from the Atlantic coast of South America.

Exploring the phylogenetic signal of morphological traits using geometric morphometry represents a powerful approach to assess the relative weights of convergence and shared evolutionary history in shaping species' forms. We evaluated the phylogenetic signal in shape and size of ventral and dorsal haptoral anchors of 10 species of monogenoids (Hamatopeduncularia, Chauhanellus and Susanlimocotyle) occurring in marine catfish (Siluriformes: Ariidae) from the Atlantic coast of South America. The phylogenetic relationships among these species were mapped onto the morphospaces of shape and size of dorsal and ventral anchors. Two different tests (squared change-parsimony and Kmult) were applied to establish whether the spatial positions in the phylomorphospace were influenced by phylogenetic relationships. A significant phylogenetic signal was found between anchor form and parasite phylogeny. Allometric effects on anchor shape were non-significant. Phylogenetically distant species on the same host differed markedly in anchor morphology, suggesting little influence of host species on anchor form. A significantly higher level of shape variation among ventral anchors was also found, suggesting that the evolutionary forces shaping ventral anchor morphology may operate with differing intensities or exhibit distinct mechanisms compared to their dorsal counterparts. Our results suggest that phylogenetic relationships were a key driver of changes in shape (but not size) of anchors of monogenoids of South American ariids. However, it seems that the emergence of the digitiform haptor in Hamatopenducularia and in some species of Chauhanellus played an important role in the reduction in anchor size and may cause secondary losses of anchors in other groups of monogenoids.

Species of Dactylogyridae (Platyhelminthes: Monogenoidea) infecting marine fishes of Moreton Bay, Queensland, Australia, with proposals of Pleuronectitrema n. gen. and Ecnomotrema n. gen. and descriptions of 13 new species.

Twenty-nine dactylogyrid species were reported from teleosts collected during a survey of the parasites of fishes of Moreton Bay, Queensland, Australia, in 2016. Two new genera, Ecnomotrema n. gen. and Pleuronectitrema n. gen., were proposed, and 13 new species were illustrated and described: Atherinicus difficilis n. sp., Diversohamulus similis n. sp., and Ecnomotrema cetiosum n. sp. from Atherinomorus vaigiensis; Haliotrema apiculum n. sp. from Pempheris schwenkii; Haliotrema tugulduriforme n. sp. from Scarus ghobban; Lethrinitrema australiense n. sp., and Lethrinitrema lituus n. sp. from Lethrinus nebulosus; Tetrancistrum siganioides n. sp. from Siganus fuscescens; Ligophorus bostrychus n. sp. from Planiliza subviridis; Neohaliotrema gemmula n. sp. from Abudefduf vaigiensis; Neohaliotrema moretonense n. sp. from Ab. vaigiensis and Ab. bengalensis; and Pleuronectitrema spirula n. sp. from Pseudorhombus arsius (all from Moreton Bay); Pleuronectitrema kuwaitense Kritsky & Sey n. sp. was described from specimens collected from P. arsius in Kuwait during 1996. Ten new host records were recorded: Chauhanellus duriensis Lim, 1994 and Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969 from Pararius proximus; Diplectanotrema sp. 1 and sp. 2 from Sillago maculata and Goniistius vestitus, respectively; Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969 from At. vaigiensis; Hal. cf. dempsteri (Mizelle & Price, 1964) Young, 1968 from Prionurus microlepidotus; Hal. spirale Yamaguti, 1968 from Upeneus tragula; Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985 from Planiliza subviridis; and Neohaliotrema malayense Lim & Gibson, 2010 from Ab. bengalensis and Ab. whitleyi. Twenty-five new faunal records for Moreton Bay were recorded, including the new species listed above and C. duriensis, Diplectanotrema sp. 1 and sp. 2, Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969, Glyphidohaptor phractophallus Kritsky, Galli, & Yang, 2007, Hal. cf. dempsteri, Hal. johnstoni Bychowsky & Nagibina, 1970, Hal. spirale, Yamaguti, 1968 Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969, Lethrinitrema nebulosum Sun, Li, & Yang, 2014, Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985, Ligophorus parvicopulatrix Soo & Lim, 2012, and Neohaliotrema malayense Lim & Gibson, 2010. Three new combinations were proposed: Hal. spariense Roubal, 1981 as Euryhaliotrema spariense (Roubal, 1981) n. comb.; and Hal. arsiosa Venkatanarasaiah, 1984 and Hal. youngi Venkatanarasaiah, 1984 as Pleuronectitrema arsiosa (Venkatanarasaiah, 1984) n. comb. and Pleuronectitrema youngi (Venkatanarasaiah, 1984) n. comb., respectively; Haliotrema sp. of Zhang is transferred to Pleuronectitrema as Pleuronectitrema sp. Hal. ctenochaeti Yamaguti, 1968 was replaced with Hal. asymphylum n. nom. to remove it from homonymy with Hal. ctenochaeti Young, 1968. Pseudohaliotrematoides zancli Yamaguti, 1968 was transferred to Haliotrema as Haliotrema hawaiiense n. nom. Hal. zancli Yamaguti, 1968 was considered a junior subjective synonym of Hal. dempsteri.

Title: Espèces de Dactylogyridae (Platyhelminthes, Monogenoidea) infectant les poissons marins de Moreton Bay, Queensland, Australie, avec la proposition de Pleuronectitrema n. gen. et Ecnomotrema n. gen. et la description de 13 nouvelles espèces. Abstract: Vingt-neuf espèces de Dactylogyridae sont signalées chez des téléostéens collectés lors d'une étude des parasites des poissons de Moreton Bay, Queensland, Australie, en 2016. Deux nouveaux genres, Ecnomotrema n. gen. et Pleuronectitrema n. gen., sont proposés, et 13 nouvelles espèces sont illustrées et décrites : Atherinicus difficilis n. sp., Diversohamulus similis n. sp., et Ecnomotrema cetiosum n. sp. d'Atherinomorus vaigiensis ; Haliotrema apiculum n. sp. de Pempheris schwenkii ; Haliotrema tugulduriforme n. sp. de Scarus ghobban ; Lethrinitrema australiense n. sp. et Lethrinitrema lituus n. sp. de Lethrinus nebulosus, Tetrancistrum siganioides n. sp. de Siganus fuscescens ; Ligophorus bostrychus n. sp. de Planiliza subviridis ; Neohaliotrema gemmula n. sp. d'Abudefduf vaigiensis ; Neohaliotrema moretonense n. sp. d'Ab. vaigiensis et Ab. bengalensis ; et Pleuronectitrema spirula n. sp. de Pseudorhombus arsius (tous de Moreton Bay). Pleuronectitrema hawaiiense Kritsky & Sey n. sp. est décrit à partir de spécimens collectés de P. arsius au Koweït en 1996. Dix nouvelles combinaisons parasites-hôtes sont répertoriées : Chauhanellus duriensis Lim, 1994 et Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969 de Pararius proximus ; Diplectanotrema sp. 1 et sp. 2, respectivement de Sillago maculata et Goniistius vestitus ; Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969 d'At. vaigiensis ; Hal. cf. dempsteri (Mizelle & Price, 1964) Young, 1968 de Prionurus microlepidotus ; Hal. spirale Yamaguti, 1968 d'Upeneus tragula ; Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985 de Planiliza subviridis ; et Neohaliotrema malayense Lim & Gibson, 2010 d'Ab. bengalensis et Ab. whitleyi. Vingt-cinq nouveaux signalements fauniques pour la baie Moreton sont rapportés, y compris les nouvelles espèces énumérées ci-dessus et C. duriensis, Diplectanotrema sp. 1 et sp. 2, Diversohamulus tricuspidatus Bychowsky & Nagibina, 1969, Glyphidohaptor phractophallus Kritsky, Galli et Yang, 2007, Hal. cf. dempsteri, Hal. johnstoni Bychowsky et Nagibina, 1970, Hal. spirale, Hamatopeduncularia thalassini Bychowsky & Nagibina, 1969, Lethrinitrema nebulosum Sun, Li, & Yang, 2014, Ligophorus kaohsianghsieni (Gussev, 1962) Gussev, 1985, Ligophorus parvicopulatrix Soo & Lim, 2012, et Neohaliotrema malayense Lim et Gibson, 2010. Trois nouvelles combinaisons sont proposées : Hal. spariense Roubal, 1981 comme Euryhaliotrema spariense (Roubal, 1981) n. comb. ; Hal. arsiosa Venkatanarasaiah, 1984 et Hal. youngi Venkatanarasaiah, 1984, respectivement comme Pleuronectitrema arsiosa (Venkatanarasaiah, 1984) n. comb. et Pleuronectitrema youngi (Venkatanarasaiah, 1984) n. comb. ; Haliotrema sp. de Zhang est transféré à Pleuronectitrema sous le nom de Pleuronectitrema sp. Hal. ctenochaeti Yamaguti, 1968 est remplacé par Hal. asymphylum n. nom. pour supprimer l'homonymie avec Hal. ctenochaeti Young, 1968. Pseudohaliotrematoides zancli Yamaguti, 1968 est transféré à Haliotrema sous le nom de Haliotrema hawaiiense n. nom. Hal. zancli Yamaguti, 1968 est considéré comme un synonyme subjectif junior de Hal. dempsteri.

Monogenoidea Communities Differ Between Male Morphotypes of Bluegill Sunfish (Lepomis macrochirus).

PURPOSE: Bluegill sunfish (Lepomis macrochirus) are a North American sport fish that exhibit two different male morphotypes. Alpha-males are large, colorful, territorial, and have significant parental investment, while ß-males are small, drab, and have two reproductive phenotypes, neither of which involves parental investment. Due to the two different reproductive strategies, the level of interaction between congenerics varies, which may impact parasites that are spread via close contact, such as Monogenoidea that infect the gills. Monogeneans are ectoparasites on the gills and skin of fish hosts that may cause significant pathology in high numbers and be an indicator of host behavior and interaction between hosts. METHODS: In this study, 328 L. macrochirus (106 α-males, 92 ß-males, and 130 females) were necropsied from 8 lakes and ponds in northwestern Virginia to identify and enumerate monogenean parasites from the gills. RESULTS: Alpha-males had a significantly greater parasite abundance and species richness compared to ß-males. This may be due to the increased size and surface area of gills in α-males, increased interaction with females during mating, and stationary behavior when guarding nests, which enhanced the chances of α-males contracting the parasites. This also led to significant differences in the monogenean communities infecting the two morphotypes, which were also significantly influenced by the size of the hosts. CONCLUSIONS: It is important in future studies regarding parasitism that behavioral morphotypes within a sex, such as α-male and ß-male L. macrochirus in this study, be treated separately as behavioral and morphometric differences between them can potentially lead to differences in parasitism.

A New Species of Unibarra (Monogenoidea, Dactylogyridae) Parasite of Oxydoras niger From Juruá River, State of Acre, Brazil and New Data for U. paranoplatensis.

Monogenoids are ectoparasites that have a simple one-host lifecycle, high species diversity, and a relatively high host specificity. During studies on the helminth fauna of fishes from the Jurua River, in Acre State, Brazil, a new species of the monotypic genus Unibarra Suriano & Incorvaia, 1995 was found parasitizing Oxydoras niger Valenciennes, 1821. Unibarra juruaensis n. sp. is allocated in the genus based on the presence of a single haptoral bar, marginal hooks similar in shape and size, gonads partially overlapping, and a conspicuous filament which connects the base of the male copulatory organ with the accessory piece. The new species differs from the only species of the genus by the smaller size of the body and of the structures, by the morphology of copulatory complex, with an accessory piece thinner than that of U. paranoplatensis Suriano & Incorvaia, 1995 and by the presence of two eyespots. The type species, U. paranoplatensis, is referred in a new host, Pimelodus blochii Valenciennes, 1840, with new morphological data. A table of measurements of the new species and previous and the present reports of U. paranoplatensis is presented.

Diversification processes between monogenoids (Dactylogyridae) and their marine catfish (Siluriformes: Ariidae) from the Atlantic coast of South America.

Due to their high specificity, monogenoids from fish provide an interesting model to study historical associations of hosts and parasites. High agreement between host and parasite phylogeny is often interpreted as evidence of cospeciation. However, cophylogenetic signal may also arise from other, either adaptive or non-adaptive, processes. We applied the recently developed Cophylospace Framework to better understand the evolutionary relationship between monogenoids and marine catfish from the Atlantic coast of South America. The associations between 12 marine catfish and 10 monogenoid species were assessed. Molecular data of host and parasite species were used for phylogenetic reconstruction. We used anchor morphology based on Procrustes coordinates to evaluate whether closely related hosts are associated with morphologically similar parasites. To assess the association between parasite phylogeny and host morphology, we produced a distance matrix based on morphological characters of catfishes. Agreement between phylogenies and between phylogeny and morphology was measured using Procrustes R2 computed with PACo. The parasite phylogeny obtained in this study represents the first complete phylogenetic hypothesis of monogenoids parasitizing ariids from South America. The Cophylospace analysis suggested that phylogenetic and morphological distance of monogenoids contributes similarly to explain the pattern of host­parasite associations, whereas parasite phylogeny is more strongly associated with the morphological traits of the hosts than with host phylogeny. This evidence suggests that cospeciation is not a major force accounting for diversification in the monogenoids studied. Rather host morphological traits seem to be a more important driver, which conforms with evidence from other host‒monogenoid systems.

Bychowskicotylids (Monogenoidea: Gastrocotylinea) infecting the gills of the sweetlips Diagramma labiosum Macleay (Haemulidae) in Moreton Bay, Queensland, Australia, with the proposal of Lebedevia n. gen. and description of Lebedevia lebedevi n. sp.

Two species of Bychowskicotylidae (Monogenoidea: Gastrocotylinea) were collected from the gills of the sweetlips Diagramma labiosum Macleay (Haemulidae) obtained from Moreton Bay, Queensland, Australia, during January 2016. Lebedevia n. gen. is proposed for bychowskicotylids having 1) a bilaterally symmetrical haptor with four pairs of gastrocotylid-like clamps and lacking an armed lappet (anchors and hooks absent); 2) longitudinal sclerotized internal ridges lining the vas deferens, 3) an unarmed male copulatory organ, and 4) four interconnected vesicles located posterior to the genital atrium and lying on the body midline dorsal to the uterus and ventral to the vas deferens. Lebedevia lebedevi n. sp., the type and only species of the genus, is described, and Tonkinopsis transfretanus Lebedev, 1972 is recorded for the first time in Moreton Bay. Yamaguticotyla Price, 1959 (Bychowskicotylidae) is considered nomen nudum, and the authorship of the genus is corrected to Yamaguticotyla Yamaguti, 1963.

First Record of a Polystome from Alligator Snapping Turtle, Macrochelys temminckii (Cryptodira: Chelydridae) or Mississippi; with Comments on "Neopolystoma orbiculare (Stunkard, 1916)" and Its Junior Subjective Synonyms.

Herein, we describe several newly-collected specimens of Neopolystoma cf. orbiculare from the urinary bladder of 2 alligator snapping turtles, Macrochelys temminckii (Troost in Harland, 1835) (Cryptodira: Chelydridae Gray, 1831) from Comet Lake (30°35'46.94″N, 88°36'3.12″W), Pascagoula River, Mississippi. Our specimens differed from all previous descriptions of N. orbiculare and its junior subjective synonyms by the combination of having intestinal ceca adorned with triangular pockets and that terminate dorsal to the haptor, distinctive hooklets each having a handle and guard of approximately equal length and having a much longer and curved blade, 16 genital coronet spines that each possess 1-2 flanges per spine, pre-testicular vaginal pores, and vaginal ducts that are anterior to the junction of the oviduct and genito-intestinal canal. Some of our specimens were enantiomorphic (4 and 3 had a dextral and sinistral ovary, respectively). Nucleotide sequences (large subunit ribosomal DNA [28S], small subunit ribosomal DNA [18S], and cytochrome oxidase subunit 1 mitochondrial gene [COI]) for our specimens were most similar to GenBank sequences ascribed to N. orbiculare. Single-gene and concatenated phylogenetic analyses confirmed that NeopolystomaPrice, 1939 is polyphyletic and that our isolates share a recent common ancestor with those ascribed to N. orbiculare. This is the first record of a polystomatid from Mississippi, from the Pascagoula River, and from the alligator snapping turtle (and only the second species of Neopolystoma reported from any snapping turtle).

New Species of Rhabdosynochus Mizelle and Blatz 1941 (Monogenoidea: Diplectanidae) From the Gills of the Cultured Centropomus viridis (Perciformes) in the Mexican Eastern Tropical Pacific.

PURPOSE: There are currently nine monogenoidean species of Rhabdosynochus infecting the gill lamellae of wild and cultured centropomid fishes from tropical and subtropical waters of the western Atlantic and eastern Pacific Oceans. The purpose of the present study was to describe the morphological distinctiveness of two new species of Rhabdosynochus found on the cultured Centropomus viridis collected from floating cages from the Mexican eastern Tropical Pacific in 2018. METHODS: monogenoideans were fixed with 4-5% formalin solution, observed and measured as temporary or permanent mounts stained with Gomori's trichrome, and mounted in Canada balsam. Other specimens were mounted on slides using a mixture of lactic acid (LA) and glycerin-ammonium picrate (GAP) and then remounted in Canada balsam to obtain measurements of the haptoral structures and copulatory complex. Illustrations were prepared with the aid of a drawing tube using a Leica microscope DM 2500 with Nomarski interference contrast. RESULTS: Rhabdosynochus viridisi n. sp. is mainly differentiated from all other congeneric species in the shape and size of their copulatory complexes, i.e., length 75-105 µm vs. 45-55 µm in R. alterinstitus, 26-44 µm in R. volucris, 19-22 µm in R. lituparvus, 21-37 µm in R. siliquaus, 48-75 µm in R. hargisi, 37-44 µm in R. hudsoni and 44-61 µm in R. guanduensis. Rhabdosynochus pacificus n. sp. differs from all other species of the genus in having an accessory piece (one subunit) distally twisted. CONCLUSIONS: Based on the morphometric differences of the two new species described above, the number of valid species of Rhabdosynochus has now increased to 11. These two new species of Rhabdosynochus represent the first described species of the genus on C. viridis.

Monogenoidea parasites of Oreochromis niloticus submitted to ractopamine supplemented diet from cultivated system / [Monogenoidea parasitos de Oreochromis niloticus provenientes de sistema de cultivo submetidos a uma dieta suplementada com ractopamina]

Oreochromis niloticus (Linnaeus) (Perciformes: Cichlidae), commonly named "tilapia", is the second most cultivated species in the world. Among the diseases that affect tilapia are parasitic diseases caused by parasites of the class Monogenoidea. The aim of the present study was to analyze parasitism rates among specimens of O. niloticus in farming systems, after dietary supplementation with ractopamine, a growth promoter that is used for fattening fish. The action of this substance on the quantitative parameters of infestation by Monogenoidea was evaluated. Samples of O. niloticus were obtained from a fish farm in Brasília, Federal District, Brazil. Their gills were removed and fixed. Four species of monogenoideans were collected: Cichlidogyrus halli, C. sclerosus, C. thurstonae and Scutogyrus longicornis. The results from this study indicate that the monogenoidean parasites of tilapias examined here presented different behaviors in relation to the ractopamine concentrations that were added to the food. The parasitological indexes did not present significant reductions through using ractopamine, thus leading to the conclusion that administration of ractopamine is not efficient as a method for controlling infestations of monogenoidean parasites.(AU)

Oreochromis niloticus (Linnaeus) (Perciformes: Cichlidae), tilápia, é a segunda espécie mais cultivada no mundo. Entre outras doenças que afetam a tilápia, estão as doenças provocadas por parasitos da classe Monogenoidea. O presente estudo teve como objetivo analisar os índices de parasitismo em espécies de O. niloticus provenientes de sistemas de cultivo, submetidos a uma dieta com suplementação de ractopamina, usada como promotor de crescimento no estágio de engorda dos peixes, para avaliar as ações dessa substância nos parâmetros quantitativos da infestação por Monogenoidea. Exemplares de O. niloticus obtidos na piscicultura "Agropecuária do Buriti Perdido", em Brasília, Distrito Federal, Brasil, foram examinados; as brânquias foram removidas e fixadas. Quatro espécies foram coletadas: Cichlidogyrus halli, C. sclerosus, C. thurstonae e Scutogyrus longicornis. Os resultados obtidos no presente estudo indicaram que as espécies de Monogenoidea parasitos de tilápia examinadas apresentam diferentes comportamentos relacionados à concentração de ractopamina adicionada ao alimento. Os índices parasitológicos não apresentaram redução significativa pelo uso da ractopamina, levando à conclusão de que a ractopamina não é eficiente como método de controle parasitário em infestações por Monogenoidea.(AU)

Revision of monogeneans parasitising Lythrurus (Cypriniformes: Leuciscidae) in eastern U.S.A., with description of Dactylogyrus lythruri sp. n. and new records of Dactylogyrus crucis Rogers, 1967 (Monogenoidea: Dactylogyridae).

A revisionary study revealed two species of monogeneans, Dactylogyrus crucis Rogers, 1967 and Dactylogyrus lythruri sp. n., parasitising Lythrurus Jordan (formerly a subgenus of Notropis Rafinesque, 1818). New records and updated taxonomy of seven of 12 known minnows of the genus of Lythrurus are provided for D. crucis. A record of Dactylogyrus attenuatus Mizelle et Klucka, 1953 (syn. Dactylogyrus umbratilus [Kimpel, 1939], nomen nudum) on Lythrurus umbratilis (Girard) is referrable to D. crucis. Dactylogyrus lythruri is described from eight species of Lythrurus. It most closely resembles Dactylogyrus beckeri Cloutman, 1987, but is distinguished by having a smaller base of the male copulatory organ (MCO) and lacking a ventral enlargement of the distal end of the basal process. Previous reports of Dactylogyrus banghami Mizelle et Donahue, 1944 and Dactylogyrus cf. beckeri Cloutman, 1987 from Lythrurus atrapiculus (Snelson) and Lythrurus bellus (Hay) from Alabama, and Dactylogyrus confusus Mueller, 1938 from L. umbratilis in Illinois are herein relegated to D. lythruri. Four species of Lythrurus appeared not to be infected with Dactylogyrus.

Neotropical Monogenoidea. 63. Atopogyrodactylus praecipuus gen. et sp. n. (Gyrodactylidae), an oviparous gyrodactylid from the external surface of a bristlenose catfish Ancistrus sp. (Siluriformes: Loricariidae) from the Rondônian Amazon, Brazil.

Atopogyrodactylus n. gen. (Gyrodactylidae) is proposed for Atopogyrodactylus praecipuus n. sp. (type species by monotypy), a protandrous and oviparous gyrodactylid from the external surfaces of an unidentified bristlenose catfish Ancistrus sp. (Siluriformes: Loricariidae) from the head waters of the Rio Candeias in the State of Rondônia, Brazil. The new genus contains species morphologically similar to those of Nothogyrodactylus Kritsky Boeger, 1991 as shown by members of both genera having accessory copulatory sclerites associated with the male copulatory organ (MCO). Atopogyrodactylus differs from Nothogyrodactylus by its species lacking haptoral bars and having a sclerotized haptoral plate overlying the ventral anchors. The new species most closely resembles Nothogyrodactylus amazonicus Kritsky Boeger, 1991 by possessing a flared proximal filament on the egg and a single morphologically similar accessory copulatory sclerite associated with an allantoid MCO.

Dactylogyrus pisolabrae n. sp. (Monogenoidea: Dactylogyridae) Parasitizing the Pealip Redhorse, Moxostoma pisolabrum (Teleostei: Catostomidae), from Oklahoma, U.S.A.

A new species of monogenean, Dactylogyrus pisolabrae n. sp., was found parasitizing the gills of the Pealip Redhorse, Moxostoma pisolabrum, from Oklahoma. Dactylogyrus pisolabrae is morphologically similar to Dactylogyrus apos, Dactylogyrus atripinnei, Dactylogyrus duquesnei, and Dactylogyrus niger, all parasitizing other species of suckers, by possessing a robust, sickle-shaped male copulatory organ, but differs from these and all other species of North American Dactylogyrus by possessing 2 unique wing-like projections opposite each other on the proximal portion of the accessory piece. Dactylogyrus pisolabrae represents the first monogenean reported from the Pealip Redhorse.

Prevalence and Intensity of Cornudiscoides Agarwali (Monogenoidea) on the Gills of Day's Mystus (Mystus Bleekeri) in Relation to Some Ecological and Biological Factors from Arunachal Pradesh, India.

This work investigated the relationship of host size, seasons, and water quality parameters with the prevalence and intensity of Cornudiscoides agarwali on Mystus bleekeri collected from the Dikrong River in Arunachal Pradesh, India from February 2016 to January 2017. A total of 2760 specimens of C. agarwali were recovered from 114 individuals of M. bleekeri. The levels of mean intensity, but not the prevalence, of infection of C. agarwali were positively correlated with fish host size, peaking in the largest size class (45.20 ± 5.69 parasites/fi sh). The prevalence values had a statistically significant seasonal trend, reaching highest (100 %) during the pre-monsoon season, followed by 91.8% during the post-monsoon period and 87.5 % during the monsoon season. The levels of mean intensity of infection were also dependent on the seasons, reaching significantly higher levels during the pre-monsoon season (42.75 ± 4.18 parasites/fi sh). All water quality parameters measured were within the safety value recommended for freshwater aquaculture. Cornudiscoides agarwali maintained its prevalence above 87.5 % throughout the annual cycle, which means it was able to reproduce year-round in a non-polluted river. This could be an indication of monogenoidean community and population dynamics thriving best under optimum water quality parameters. Also, this article draws the attention of parasitologists and ichthyologists to a taxonomic problem of the misidentification of Mystus spp., and therefore, possibly of their parasitic monogenoids.

Monogenoidea (Dactylogyridae, Gyrodactylidae) from Red River Pupfish, Cyprinodon rubrofluviatilis (Cyprinodontiformes: Cyprinodontidae), from Kansas and Texas, USA.

BACKGROUND: The gills of Red River Pupfish (Cyprinodon rubrofluviatilis) collected from Kansas and Texas, U.S.A., were found to be infected with three monogenoideans, Fundulotrema prolongis, Gyrodactylus rubrofluviatilae n. sp., and a species of Salsuginus. RESULTS: Gyrodactylus rubrofluviatilae n. sp. appears to be a member of a group of six closely related species possessing hamuli with mesially folded roots and a linguiform ventral bar shield, and parasitizing closely related species of Cyprinodon of the North American Gulf Coast and inland waters of the Southwestern United States and northern México. Gyrodactylus rubrofluviatilae n. sp. differs from its close congeners in the morphology of the hamuli, ventral bar, ventral bar shield, and marginal hooks. Because the morphology of the male copulatory complex was not determined of what we believe will eventually be a new species of Salsuginus, a species description is deferred. This is the first report of any parasite from this host. CONCLUSIONS: Many North American species currently recognized within the Cyprinodontiformes have not yet been surveyed for species of Fundulotrema, Gyrodactylus, or Salsuginus. This, coupled with the high host specificity generally recognized for these monogeneans, portends there are likely additional new species yet to be discovered. When possible, to help augment morphological data, further studies should employ comprehensive intra- and interspecies molecular analyses to help resolve host-parasite phylogenies.

Euryhaliotrema spp. (Monogenoidea: Dactylogyridae) Parasitic on the Gill Lamellae of Perciform Fishes in Moreton Bay, Queensland, Australia, with the Description of Euryhaliotrema solenophallus sp. nov. from the Silver Moony Monodactylus argenteus (Linnaeus) (Monodactylidae).

BACKGROUND: The present paper represented the third installment on the monogenoidean parasites collected during a workshop exploring the diversity of the parasites of fishes in Moreton Bay, Queensland, Australia. Previous reports on monogenoids collected during the workshop included species parasitizing beloniform and gerreid fishes. PURPOSE: During January 2016, the author, having responsibility for the identification and description of monogenoids, participated in a workshop supported by an Australian Biological Resources Study Grant to Drs. Thomas Cribb and Scott Cutmore, University of Queensland, to explore the diversity of parasites infecting the fishes of Moreton Bay, Queensland, Australia. METHODS: Approximately 100 species of marine fishes were necropsied for parasites. Standard procedures for collecting, mounting, drawing, and measuring of monogenoids were employed. RESULTS: A new species of Euryhaliotrema was collected and described from the silver moony Monodactylus argenteus (Monodactylidae) and the first recording of Euryhaliotrema spirotubiforum on the dory snapper Lutjanus fulviflamma and Russell's snapper Lutjanus russellii (both Lutjanidae) in Moreton Bay was reported. CONCLUSION: The results suggested that the diversity of dactylogyrids off eastern Australia is under estimated in the literature.

Monogenoids (Polyonchoinea, Dactylogyridae) from Hydrolycus armatus (Characiformes, Cynodontidae) with the description of a new species of Rhinoxenus and the proposal of a new genus from the Xingu River, Pará, Brazil.

One new species of Rhinoxenus Kritsky, Boeger & Thatcher, 1988 from the nasal cavities and four new species of Mymarothecioides n. gen. from the gills are described in Hydrolycus armatus (Jardine & Schomburgk). They were collected in the Xingu River, Pará, Brazil. Rhinoxenus cachorra n. sp. is characterized by having a ventral anchor with inconspicuous roots, and point with fish-hook-like termination; copulatory complex comprising a spiraled male copulatory organ (MCO) with two counterclockwise coils, and an accessory piece with an expanded, bifurcated distal portion. Mymarothecioides n. gen. is proposed and characterized for species without eyes, with or without accessory chromatic granules; copulatory complex comprising articulated MCO, accessory piece; MCO a broad arcuate tube; an accessory piece with a hooked termination in the distal portion; a dextro or midventral non-sclerotized vagina; an anteromedial projection on the ventral bar. Mymarothecium whittingtoni Kritsky, Boeger & Jégu, 1996 is transferred to Mymarothecioides n. gen. as Mymarothecioides whittingtoni (Kritsky, Boeger & Jégu, 1996) n. comb.

Metazoan parasite communities of Leporinus macrocephalus (Characiformes: Anostomidae) in cultivation systems in the western Amazon, Brazil / Comunidade de metazoários parasitos de Leporinus macrocephalus (Characiformes: Anostomidae) em sistemas de cultivo no oeste da Amazônia, Brasil

ABSTRACT In the Amazon, the growing demand for fish has been boosting the expansion of fish farms. However, the intensification of cultivation can generate disequilibrium in the parasite-host environment, predisposing fish to parasitic infections. The objective of this study was to evaluate the community structure of metazoan parasites in cultivation systems of piauçu, Leporinus macrocephalus, in the state of Acre, Brazil. We examined 100 specimens from a semi-intensive cultivation system (earth tanks) and 100 from an extensive system (dams). Overall 66.5% of the hosts were parasitized. We collected 1,240 parasite specimens, classified in 15 metazoan taxa (10 monogenoidean, one digenean and four nematodes). The parasite prevalence was higher by Monogenoidea in the dams, and by Nematoda in the earth tanks. The parasitic indexes were, in general, low and varied among species. Monogeneoidea had higher values for quantitative and ecological descriptors of parasitism in the dams, while Nematoda had higher values in the earth tanks. A single species of Digenea was found in the dams, with low prevalence. No taxon was classified as central. In the dams, parasite abundance was correlated only with total fish length, while in the earth tanks, it was positively correlated with total length, weight and condition factor of fish. The endoparasite and ectoparasite infracommunities presented higher richness, dominance, diversity and evenness, respectively, in the earth tanks and in the dams. This is the first study of ecological descriptors of parasites of L. macrocephalus in the Amazon.

RESUMO Na Amazônia, a crescente demanda por pescado vem impulsionando a expansão da piscicultura. No entanto, a intensificação dos cultivos pode gerar desequilíbrio no sistema parasito-hospedeiro-ambiente, predispondo os peixes a infecções parasitárias. O objetivo deste estudo foi avaliar a estrutura das comunidades de metazoários parasitos de piauçu, Leporinus macrocephalus, em sistemas de cultivo no estado do Acre, Brasil. Foram coletados 200 peixes, sendo 100 espécimes de sistema de cultivo semi-intensivo em viveiro escavado e 100 de sistema extensivo em açude. Dos 200 hospedeiros analisados 66,5% estavam parasitados. Foram coletados 1.240 espécimes de metazoários, classificados em quinze espécies (10 de Monogenoidea, uma de Digenea e quatro de Nematoda). A prevalência de parasitismo por Monogenoidea foi maior em açude e por Nematoda em viveiro. De forma geral, os índices de parasitismo foram baixos e variaram entre as espécies, com maiores valores dos descritores quantitativos e ecológicos do parasitismo por Monogenoidea em açude e Nematoda em viveiro. A única espécie de Digenea foi encontrada em açude e com baixa prevalência. Nenhum táxon foi classificado como central. Nos açudes, a abundância parasitária foi correlacionada apenas com o comprimento total dos hospedeiros, e nos viveiros com o comprimento total, peso e fator de condição dos hospedeiros. Nos viveiros, a infracomunidade de endoparasitos apresentou os maiores índices de riqueza, dominância, diversidade e equitabilidade. Nos açudes, os ectoparasitos apresentaram os maiores índices. Este foi o primeiro registro de índices parasitários de L. macrocephalus em sistemas de cultivo na Amazônia.

Moderate pathogenic effect of Ligophorus uruguayense (Monogenoidea, Ancyrocephalidae) in juvenile mullet Mugil liza (Actinopterygii, Mugilidae) from Brazil

ABSTRACT Monogenoidea pathogenic activity can elicit various histological responses in fish. Species of Ligophorus are specific parasites of mullets, and its relationship with host fish may result in a moderate pathogenic action. In order to ascertain this relationship, estuarine mullets (Mugil liza) were collected in an estuary, reared in laboratory, for three weeks, and forwarded for histological and parasitological analyses. Ligophorus uruguayense (Monogenoidea) infestation in the gills of the mullets was identified. The severe infestation by only one species of Monogenoidea may result from the specificity of these parasites to mullets. Mullets submitted to histological analysis exhibited respiratory epithelium detachment; mild, moderate and severe hyperplasia of the respiratory epithelium; atrophy; and telangiectasia of the gills. This is the first study reporting that mullets highly infested by Monogenoidea can show mild (100%) to severe (20%) gill changes with a distinct frequency of occurrence. Because of the high prevalence of mild alterations observed, it is possible to accept that L. uruguayense is moderately pathogenic to M. liza, even during high prevalence and intensity of infestation, as a result of its specificity.

Metazoan parasite communities of Leporinus macrocephalus (Characiformes: Anostomidae) in cultivation systems in the western Amazon, Brazil / Comunidade de metazoários parasitos de Leporinus macrocephalus (Characiformes: Anostomidae) em sistemas de cultivo no oeste da Amazônia, Brasil

ABSTRACT In the Amazon, the growing demand for fish has been boosting the expansion of fish farms. However, the intensification of cultivation can generate disequilibrium in the parasite-host environment, predisposing fish to parasitic infections. The objective of this study was to evaluate the community structure of metazoan parasites in cultivation systems of piauçu, Leporinus macrocephalus, in the state of Acre, Brazil. We examined 100 specimens from a semi-intensive cultivation system (earth tanks) and 100 from an extensive system (dams). Overall 66.5% of the hosts were parasitized. We collected 1,240 parasite specimens, classified in 15 metazoan taxa (10 monogenoidean, one digenean and four nematodes). The parasite prevalence was higher by Monogenoidea in the dams, and by Nematoda in the earth tanks. The parasitic indexes were, in general, low and varied among species. Monogeneoidea had higher values for quantitative and ecological descriptors of parasitism in the dams, while Nematoda had higher values in the earth tanks. A single species of Digenea was found in the dams, with low prevalence. No taxon was classified as central. In the dams, parasite abundance was correlated only with total fish length, while in the earth tanks, it was positively correlated with total length, weight and condition factor of fish. The endoparasite and ectoparasite infracommunities presented higher richness, dominance, diversity and evenness, respectively, in the earth tanks and in the dams. This is the first study of ecological descriptors of parasites of L. macrocephalus in the Amazon.

RESUMO Na Amazônia, a crescente demanda por pescado vem impulsionando a expansão da piscicultura. No entanto, a intensificação dos cultivos pode gerar desequilíbrio no sistema parasito-hospedeiro-ambiente, predispondo os peixes a infecções parasitárias. O objetivo deste estudo foi avaliar a estrutura das comunidades de metazoários parasitos de piauçu, Leporinus macrocephalus, em sistemas de cultivo no estado do Acre, Brasil. Foram coletados 200 peixes, sendo 100 espécimes de sistema de cultivo semi-intensivo em viveiro escavado e 100 de sistema extensivo em açude. Dos 200 hospedeiros analisados 66,5% estavam parasitados. Foram coletados 1.240 espécimes de metazoários, classificados em quinze espécies (10 de Monogenoidea, uma de Digenea e quatro de Nematoda). A prevalência de parasitismo por Monogenoidea foi maior em açude e por Nematoda em viveiro. De forma geral, os índices de parasitismo foram baixos e variaram entre as espécies, com maiores valores dos descritores quantitativos e ecológicos do parasitismo por Monogenoidea em açude e Nematoda em viveiro. A única espécie de Digenea foi encontrada em açude e com baixa prevalência. Nenhum táxon foi classificado como central. Nos açudes, a abundância parasitária foi correlacionada apenas com o comprimento total dos hospedeiros, e nos viveiros com o comprimento total, peso e fator de condição dos hospedeiros. Nos viveiros, a infracomunidade de endoparasitos apresentou os maiores índices de riqueza, dominância, diversidade e equitabilidade. Nos açudes, os ectoparasitos apresentaram os maiores índices. Este foi o primeiro registro de índices parasitários de L. macrocephalus em sistemas de cultivo na Amazônia.