Monogenoidean Species Research Articles

Species of Dactylogyridae (Monogenoidea, Polyonchoinea) from the gills of haemulid and lutjanid fishes (Perciformes) from the Pacific coast of Mexico.

Examination of the gill lamellae of the Panama grunt Rhencus panamensis (Steindachner) (Haemulidae), golden snapper Lutjanus inermis (Peters), and yellow snapper Lutjanus argentiventris (Peters) (Lutjanidae) (Perciformes) from the coast of the Guerrero State (eastern Tropical Pacific) of Mexico revealed 5 species of Monogenoidea: Euryhaliotrema disparum n. sp. on R. panamensis; Haliotrematoides uagroi n. sp. on L. inermis; and E. anecorhizion Kritsky & Mendoza-Franco, 2012, E. fastigatum (Zhukov, 1976) Kritsky & Boeger, 2002, and E. paracanthi (Zhukov, 1976) Kritsky & Boeger, 2002 on L. argentiventris. Specimens found on R. panamensis were assigned within Euryhaliotrema as a new species possessing the atypical morphology of the male copulatory organ (i.e., a coiled tube with clockwise rings). Haliotrematoides uagroi n. sp. differs from Haliotrematoides striatohamus (Zhukov, 1981) Mendoza-Franco, Reyes-Lizama & Gonzalez-Solis, 2009 from Haemulon spp. (Haemulidae) from the Caribbean Sea (Mexico) in having inner blades on the distal shafts of the ventral and dorsal anchors. The present paper represents the first finding of a species of Euryhaliotrema (E. disparum n. sp.) on a species of Rhencus and the second species on a haemulid host, and H. uagroi n. sp. as the first monogenoidean species described on L. inermis. Euryhaliotrema anecorhizion, E. fastigatum, and E. paracanthi on L. argentiventris in the Pacific coast of Mexico represent new geographical records.

Two new species of monogenoidean parasites (Platyhelminthes: Neodermata) of ornamental fish of Loricariidae (Siluriformes) from the Xingu River, Brazilian Amazon

Two new monogenoidean species of Unilatus Mizelle & Kritsky, 1967 found in the gills of loricariids in the Lower Xingu-Iriri rivers are described: Unilatus humboldtii sp. nov. from Baryancistrus niveatus (Castelnau, 1855), Panaque armbrusteri Lujan, Hidalgo & Stewart, 2010, Pseudacanthicus sp. (type-host), and Scobinancistrus aureatus Burgess, 1994; and Unilatus luciarappae sp. nov. from P. armbrusteri. Unilatus humboldtii sp. nov. is distinguished from other congeneric species due to its anterior anchor with well-developed superficial root with depressed or truncated distal portion, and inconspicuous or reduced deep root; anterior bar with posteromedial projection; hooks of pair 1 with dilated shaft comprising 2/3 of the hook length; spiraled male copulatory organ with approximately 16–18 counterclockwise loops. Unilatus luciarappae sp. nov. is characterized by having anterior anchor with well-developed superficial root and reduced deep root, slightly curved shaft, elongated, slightly curved, and tapered point; spiraled MCO with approximately 18–19 counterclockwise loops, with median distal bulbous portion and remaining portion tapered and elongated, comprising 1/4 of the body length; and accessory piece comprising approximately 2/3 of the MCO length. More than fifty years after the description of the type species of Unilatus from an artificial environment (U.S. aquaria), this study represents the first formal record and description of Unilatus species from hosts collected in natural habitats in the Xingu River. Considering the impact of the Belo Monte dam on the formerly pristine conditions of the study region and the importance of loricariids for the ornamental fish trade, we recommend monitoring monogenoidean diversity, parasite-host interaction, as well as the dispersion patterns and pathogenicity of these parasites.

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.

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. 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. Rhabdosynochus viridisi n. sp. is mainly differentiated from all other congeneric species in the shape and size of their copulatory complexes, i.e., length 75-105µm vs. 45-55µm in R. alterinstitus, 26-44µm in R. volucris, 19-22µm in R. lituparvus, 21-37µm in R. siliquaus, 48-75µm in R. hargisi, 37-44µm in R. hudsoni and 44-61µm in R. guanduensis. Rhabdosynochus pacificus n. sp. differs from all other species of the genus in having an accessory piece (one subunit) distally twisted. 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.

Multidisciplinary investigation on the catfish parasite Hamatopeduncularia Yamaguti, 1953 (Monogenoidea: Dactylogyridae): description of two new species from India, and phylogenetic considerations

Hamatopeduncularia was erected with Hamatopeduncularis arii as the type species. This genus comprises monogenoidean species mostly found as ectoparasites of marine catfishes belonging to the Ariidae. There is a significant taxonomic ambiguity among Hamatopeduncularia species due to their morphological similarity, but so far only a few morphological studies have succeeded in addressing interspecific variation and relationships. Moreover, little molecular data is available for this genus. A multidisciplinary, integrated study consisting of morphological, morphometric and molecular analyses was conducted on different species of Hamatopeduncularia recovered from the gills of two marine catfishes, Arius jella Day and Plicofollis dussumieri (Valenciennes). Five species of Hamatopeduncularia, two of which represent new species, were investigated: H. arii, H. elongatum, H. thalassini, H. madhaviae sp. nov. and H. bifida sp. nov. Phylogenetic analysis was performed using the 18S rDNA sequence as a molecular marker. The most important results of the present work are: (1) the multidisciplinary description of two novel species; (2) the multidisciplinary redescription of two species and of the type species of the genus; (3) the first molecular characterisation of 18S rDNA sequences of five species of genus Hamatopeduncularia; and (4) molecular support for the monophyly of the genus. http://zoobank.org/urn:lsid:zoobank.org:act:1333F4CC-E497-4D0A-AD7D-276D44AE6413 http://zoobank.org/urn:lsid:zoobank.org:act:43D18F75-6F4A-4F9B-8C00-6234E5BA6526

Parasitism by Monogenoidea in Piaractus mesopotamicus (Characiformes, Characidae) cultivated in Paraná River (Brazil).

This study investigated the occurrence, prevalence, mean abundance and mean intensity of monogenoidean parasites in Piaractus mesopotamicus farmed in cages in the reservoir of the Itaipu Hydroelectric Power Station, Paraná River, Brazil. The parasite distribution pattern and the correlation of prevalence and abundance with the total length of hosts were also investigated. Four monogenoidean species were collected: Anacanthorus penilabiatus, A. toledoensis, Mymarothecium ianwhitingtoni and M. viatorum. All the parasites collected in P. mesopotamicus showed the typical aggregated distribution pattern, and the abundance and the prevalence did not shown any correlation with the total length of hosts.

New and previously described dactylogyrid species (Monogenoidea: Polyonchoinea) and a gastrocotylinean pre-adult (Heteronchoinea) from pomacentrid and caesionid (Perciformes) fishes from Lizard Island, Great Barrier Reef, Australia.

During a parasitological survey of perciform fishes from Lizard Island, Great Barrier Reef, Australia, we found the following gill monogenoidean species (Platyhelminthes): Euryhaliotrema lizardi n. sp. on Caesio caerulaurea Lacepède, 1801 (Caesionidae) (type host) and Haliotrema weberii n. sp. on Chromis weberi Fowler and Bean, 1928 (Pomacentridae) (type host), Chromis amboinensis (Bleeker, 1871), Chromis atripectoralis Welander and Schultz, 1951 and Caesio teres Seale, 1906. Euryhaliotrema lizardi n. sp. is characterized by having anchors with an elongated straight shaft and point as well as a vaginal canal with two loops before connecting to the seminal receptacle. Ha. weberii n. sp. is distinguished from other congeners by possessing a tubular male copulatory organ (MCO), partially straight. Two previously described dactylogyrids were also found: Haliotrematoides caesionis (Yamaguti, 1953) Kritsky, Yang and Sun 2009) on Caesio cuning (Bloch, 1791) and Ca. teres (new host record) and Haliotrematoides patellacirrus (Bychowsky and Nagibina, 1971) Kritsky, Yang and Sun 2009, on Ca. cuning (new host record). Finally, we provide the first report of a gastrocotylinean pre-adult on Ca. teres. We provide descriptions and illustrations of the new species and the gastrocotylinean pre-adult and include supplemental observations of Ht. caesionis and Ht. patellacirrus. The present findings expand the known spectrum of host species of Euryhaliotrema, Haliotrema and Haliotrematoides to include new caesionid and pomacentrid fishes.

Communities of parasite metazoans in Piaractus brachypomus (Pisces, Serrasalmidae) in the lower Amazon River (Brazil).

The aim of this study was to investigate the component community of parasite metazoans of Piaractus brachypomus in the lower Amazon River, northern Brazil. From 34 necropsied fish, 27,384 metazoan parasites were collected, such as Anacanthorus spathulatus, Mymarothecium viatorum and Notozothecium janauachensis (Monogenoidea); Spectatus spectatus and Contracaecum sp (Nematoda); Clinostomum marginatum and Dadaytrema oxycephala (Digenea); and Argulus carteri and Ergasilus sp. (Crustacea). The dominant species was S. spectatus followed by monogenoidean species, and there was aggregated dispersion of parasites, except for D. oxycephala and Contracaecum sp., which presented random dispersion. Positive correlation among the abundance of the three monogenoideans species were found, thus indicating that there was no competition between the species of these parasites on the gills of hosts. The abundances of some parasite species showed positive correlations with the size of the hosts, but the condition factor of the fish was not affected by the parasitism levels. It showed that this host had a metazoan community characterized by high species richness of metazoans, low evenness and high diversity of parasites, with prevalence of endoparasites, including larval stages. This was the first record of C. marginatum, A. carteri, Ergasilus sp. and Contracaecum sp. for P. brachypomus.

The mitochondrial genome of the egg-laying flatworm Aglaiogyrodactylus forficulatus (Platyhelminthes: Monogenoidea).

BackgroundThe rather species-poor oviparous gyrodactylids are restricted to South America. It was suggested that they have a basal position within the otherwise viviparous Gyrodactylidae. Accordingly, it was proposed that the species-rich viviparous gyrodactylids diversified and dispersed from there.MethodsThe mitochondrial genome of Aglaiogyrodactylus forficulatus was bioinformatically assembled from next-generation illumina MiSeq sequencing reads, annotated, and compared to previously published mitochondrial genomes of other monogenoidean flatworm species.ResultsThe mitochondrial genome of A. forficulatus consists of 14,371 bp with an average A + T content of 75.12 %. All expected 12 protein coding, 22 tRNA, and 2 rRNA genes were identified. Furthermore, there were two repetitive non-coding regions essentially consisting of 88 bp and 233 bp repeats, respectively. Maximum Likelihood analyses placed the mitochondrial genome of A. forficulatus in a well-supported clade together with the viviparous Gyrodactylidae species. The gene order differs in comparison to that of other monogenoidean species, with rearrangements mainly affecting tRNA genes. In comparison to Paragyrodactylus variegatus, four gene order rearrangements, i.e. three transpositions and one complex tandem-duplication-random-loss event, were detected.ConclusionMitochondrial genome sequence analyses support a basal position of the oviparous A. forficulatus within Gyrodactylidae, and a sister group relationship of the oviparous and viviparous forms.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1586-2) contains supplementary material, which is available to authorized users.

Monogenoidean parasites of Italian marine fish: An updated checklist

An updated checklist of the monogenoids infecting Italian marine fish is provided, including seven new records (Diplectanum simile on Sciaena umbra; Diplectanum sp. on Scorpaena porcus; Lamellodiscus elegans, L. ergensi, L. fraternus on Diplodus vulgaris; L. virgula on Pagellus erythrinus; Pseudanthocotyloides heterocotyle on Engraulis encrasicolus). The number of monogenoidean species recorded in Italian marine ichtyofauna is therefore increased to 141, harboured by 93 host species.

New species of Diplectanum (Monogenoidea: Diplectanidae), and proposal of a new genus of the Dactylogyridae from the gills of gerreid fishes (Teleostei) from Mexico and Panama

While investigating the parasites of several marine fishes from the Western Atlantic, the Southern Gulf of Mexico and Central America (Panama), the following monogenoidean species from the gills of gerreid fishes (Gerreidae) were found: Diplec-tanum gatunense sp. n. (Diplectanidae) and Octouncuhaptor eugerrei gen. et sp. n. (Dactylogyridae) in Eugerres brasilianus (Cuvier) from Gatun Lake in the Panama Canal Watershed, and Diplectanum mexicanum sp. n. in Diapterus rhombeus (Cuvier) from the coast of Campeche State, Mexico. New diplectanid species are distinguished from other species of the genus by the general morphology of the copulatory complex and by the shape of the anchors and bars on the haptor. Octouncuhaptor gen. n. is proposed for its new species having slightly overlapping gonads (testis posterodorsal to the ovary), a dextrolateral vaginal aperture, a copulatory complex consisting of a coiled male copulatory organ with counterclockwise rings with the base articulated to the accessory piece, 8 pairs of hooks and the absence of anchors and bars on haptor. Our analysis of morphological features of Diplectanum species on gerreids evidences that these parasites more closely resemble each other than the known species from sciaenids suggesting that split between gerreids and sciaenids resulted in parasite speciation.