Structure of the metazoan parasite communities of haemulid fish (Actinopterygii: Perciformes) in the South Atlantic Ocean: a comparative approach.

Haemulidae represents one of the most diverse, widespread and conspicuous families of Perciformes, in which most species are marine, some brackish and rarely from freshwater. From April 2009 to July 2012, 120 specimens of Conodon nobilis, 60 Orthopristis rubra and 50 Anisotremus virginicus were collected off the State of Rio de Janeiro, Brazil, and analyzed for metazoan parasites. A total of 16 parasite taxa were found on/in A. virginicus, 19 on/in Co. nobilis and 21 on/in O. rubra, in which ectoparasites were most common on A. virginicus and Co. nobilis and endoparasites in O. rubra. All parasites showed aggregate pattern of distribution (discrepancy index values higher than 0.70). Mean abundance, species richness and Brillouin index (diversity) differed among the host species, i.e., O. rubra showed the highest values, followed by A. virginicus and Co. nobilis with intermediate and lowest values, respectively. At infracommunity level was possible to observe high similarity of parasite composition among the three host species. The digeneans Leurodera decora and Monorchis latus, and the acanthocephalan Koronacantha sp. represent new locality records off Brazil. Moreover, five, four and two taxa are reported, for the first time, parasitizing Co. nobilis, A. virginicus and O. rubra, respectively.

Proposal of Cynoscionella n. g. (Monogenea: Diplectanidae), with description of a new species from the gills of Cynoscion phoxocephalus (Actinopterygii: Sciaenidae) in Peru and reassignment of two species of Diplectanum Monticelli, 1903.

Cynoscionella n. g. is proposed for Cynoscionella sanmarci n. sp. and two previously described species of Diplectanum Diesing, 1858 were reassigned into the new genus. The three species are gill parasites of sciaenid fishes (Perciformes: Sciaenidae). The new genus is closely related with Diplectanum (sensu stricto), but is mainly distinguished by its male copulatory organ (MCO) having a slightly sclerotized sleeve-shaped base, lacking accessory piece and accessory copulatory organ. In addition, Cynoscionella n. g. differs from Diplectanum species by having the ventral anchors with well-developed roots, and a prostatic reservoir simple. Cynoscionella sanmarci n. sp. is a parasite of the cachema weakfish Cynoscion phoxocephalus Jordan & Gilbert, a demersal teleost collected from off the coastal zone of Puerto Pizarro, Tumbes region, northern Peru. Diplectanum bilobatum Hargis, 1955 from the spotted weakfish Cynoscion nebulosus (Cuvier) and D. monticellii Domingues & Boeger, 2003 from the smooth weakfish Cynoscion leiarchus (Cuvier), are transferred to Cynoscionella n. g. as Cy. bilobatum (Hargis, 1955) n. comb. and Cy. monticelli (Domingues & Boeger, 2003) n. comb. The present finding represents the first data on the monogenean parasites of C. phoxocephalus. This is the thirteenth marine diplectanid species recorded from Peru.

Cucullanus pinnai pinnai and C. pinnai pterodorasi (Nematoda Cucullanidae): what does the integrative taxonomy tell us about these species and subspecies classification?

Cucullanus pinnai has been divided in two subspecies (C. pinnai pinnai and C. pinnai pterodorasi) based on the morphology of oesophastome. While C. pinnai pinnai apparently shows low host specificity and broad geographic occurrence, with certain morphological variations, C. pinnai pterodorasi was reported once, parasitizing Pterodoras granulosus. We used an integrative taxonomic approach to evaluate whether or not populations of C. pinnai pinnai from Trychomycterus spegazzinii (Escoipe River, Argentina) and Pimelodus fur (Miranda River, Brazil), and of C. pinnai pterodorasi from Pterodoras granulosus (Miranda River, Brazil) are conspecific. Parasites were observed using light microscopy and genetically characterized based on partial sequences of the 18S and 28S rDNA, ITS1-5.8S-ITS2, and COI mtDNA. Phylogenies were reconstructed and the Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (bPTP), and Automatic Barcode Gap Discovery (ABGD) were used for species delimitation purposes. The present samples formed well-supported monophyletic assemblages, corroborating in part the results of morphological analyses; however, they grouped according to geographic origin. Species delimitation suggested conspecificity of C. pinnai pinnai with C. pinnai pterodorasi from Brazil; consequently, the morphology of oesophastome may be an intraspecific variation. Results also indicated that C. pinnai may represent a species complex as samples from Argentina were suggestive of an independent specific entity. However, definitive affirmations are premature, since there is no autapomorphy for separating C. pinnai from Brazil and Argentina and sampling was limited to three host species from two river basins. The phylogenetic reconstructions also confirmed the artificiality of some genera within Cucullanidae.

Six new species of Rhamnocercus Monaco, Wood & Mizelle, 1954 (Monogenea: Diplectanidae) infecting the gills from South American sciaenid fishes.

A parasitological survey searching diplectanids (Monogenea: Diplecatnidae) infesting the gills of marine fishes from South America was carried out during the 2019-2020 period. The gills of four sciaenid species, 2 Cheilotrema fasciatum Tschudi, 1 smalleye croaker Nebris microps Cuvier, 2 royal highhat Pareques lanfeari (Barton), and 1 minor stardrum Stellifer minor (Tschudi), were sampled. Six new species of Rhamnocercus Monaco, Wood & Mizelle, 1954 were described: Rhamnocercus chacllae n. sp. and Rhamnocercus chaskae n. sp. from P. lanfeari, Rhamnocercus fasciatus n. sp. from C. fasciatum, Rhamnocercus microps n. sp. from N. microps, and Rhamnocercus rimaci n. sp. and Rhamnocercus tantaleani n. sp. from S. minor. Rhamnocercus chacllae n. sp. can be differentiated from its congeners by its L-shaped male copulatory organ (MCO) and by having an anteromedial slight notch at ventral bar. Rhamnocercus chaskae n. sp. differs from the other species of the genus by its long and straight MCO with bifid distal end and by having haptoral accessory spines at level of ventral bar with quadrifid distal portion. Rhamnocercus fasciatus n. sp. is characterized by possessing a straight and long MCO with truncated distal end, haptoral accessory spines at level of ventral bar with bifid distal portion, dorsal bars with a knob at lateral extremity, and a large vagina with bell-shaped. Rhamnocercus microps n. sp. differs from all congeners mainly by having a short and straight MCO with the distal end of internal tube spatulate and uncovered by external tube. Rhamnocercus rimaci n. sp. is can be distinguished from all other species of Rhamnocercus by having an almost J-shaped MCO with the distal end of external tube slight expanded and the distal end of internal tube narrow and uncovered by external tube. Rhamnocercus tantaleani n. sp. is mainly characterized by its MCO, which is tubular and straight, having the distal end of external tube bifurcated (right branch well-expanded and left branch narrow) and the distal end of internal tube enveloped by left branch of the external tube. This is the first data on the parasites of P. lanfeari, a little known, but popular fish in local markets from Peru. Rhamnocercus microps n. sp. is the first described species of Rhamnocercus in Brazil. The present finding brings to 12, the number of known species of Rhamnocercus. A key to Rhamnocercus species is provided.

New record of monogeneans (Platyhelminthes: Monogenea) infecting some marine fishes from the Peruvian coastal zone

A parasitological survey searching monogeneans infesting marine fish was carried out during June 2018 and January 2020 from the coastal zone of Puerto Pizarro, Tumbes (northern Peru) and from the coastal zone of Chorrillos, Lima (central Peru). The gills, skin, nasal cavities, or branchial gill-cover of seven species were sampled. Ten monogenean species assigned to six families and nine genera were identified. The monogeneans Callorhynchocotyle callorhynchi (Manter, 1955); Capsala biparasiticum (Goto, 1894) Price, 1938; Euryhaliotrema sagmatum Kritsky & Boeger, 2002; Listrocephalos kearni Bullard, Payne &Braswell, 2004; Magniexcipula lamothei Bravo-Hollis, 1981; Nasicola klawei (Stunkard, 1962) Yamaguti, 1968; and Pseudorhabdosynochus anulus Violante-Gonzalez & Rojas-Herrera, 2011 are registered for the first time in Peru. While Capsala gregalis (Wagner & Carter, 1967) Chisholm & Whittington, 2007; Heterocotyle margaritae Chero, Cruces, Sáez, Santos & Luque, 2020; and Monocotyle luquei Chero, Cruces, Iannacone, Sanchez, Minaya, Sáez & Alvariño, 2016 have been previously registered in Peruvian waters, however, the region of Tumbes (northern Peru) represent a new locality record for these species.

Durante junio de 2018 y enero de 2020 se realizó un levamiento parasitológico para buscar monogeneos que infectan peces marinos en la zona costera de Puerto Pizarro, departamento de Tumbes (norte de Perú) y en la zona costera de Chorrillos, departamento de Lima (centro de Perú). Se analizaron las branquias, la piel, las cavidades nasales o el opérculo de siete especies. Se identificaron diez especies de monogeneos, asignadas a seis familias y nueve géneros. Los monogeneos Callorhynchocotyle callorhynchi (Manter, 1955); Capsala biparasitica (Goto, 1894) Price, 1938; Euryhaliotrema sagmatum Kritsky y Boeger, 2002; Listrocephalos kearni Bullard, Payne y Braswell, 2004; Magniexcipula lamothei Bravo-Hollis, 1981; Nasicola klawei (Stunkard, 1962) Yamaguti, 1968; y Pseudorhabdosynochus anulus Violante-Gonzalez & Rojas-Herrera, 2011 son registrados por primera vez en Perú. Mientras que, Capsala gregalis (Wagner y Carter, 1967) Chisholm y Whittington, 2007; Heterocotyle margaritae Chero, Cruces, Sáez, Santos & Luque, 2020; y Monocotyle luquei Chero, Cruces, Iannacone, Sanchez, Minaya, Sáez & Alvariño, 2016 han sido previamente registrados en aguas peruanas, sin embargo, la región de Tumbes (norte de Perú) representa un nuevo registro de localidad para estas especies.

Bicentenariella n. g. (Monogenea: Dactylogyridae) including descriptions of three new species and two new combinations from serranid fishes (Actinopterygii: Serranidae: Anthiinae) in the South American Pacific Ocean.

Bicentenariella n. g. is proposed to accommodate three new species of dactylogyrid monogeneans found on the gills of the threadfin bass Pronotogrammus multifasciatus Gill (Perciformes: Serranidae) from the Southeastern Pacific Ocean off Peru: Bicentenariella claudiae n. sp. (type-species), B. sinuosa n. sp. and B. puertopizarroensis n. sp. Bicentenariella n. g. is mainly characterised by possessing a broadly X-shaped dorsal bar, which has the anterior arms longer than posterior ones and by having a ventral bar with two medial projections. Bicentenariella n. g. is also characterised by having: (i) anchors equal, each with elongate superficial root and short deep root; (ii) an haptor with bilaterally paired lobes, lacking haptoral reservoirs; (iii) hooks with protruded obtuse thumb and undilated shank; (iv) a tubular tapered-shaped male copulatory organ with basal flap bifurcated or not (MCO), lacking accessory piece; (v) a delicate membrane associated with the shaft of the MCO present or absent; (vi) a muscular trumpet-shaped vagina, vaginal aperture dextrolateral; (vii) eyespots absent, accessory chromatic granules present; and (viii) a not lobulated testis. Bicentenariella claudiae n. sp. is characterised by having a MCO with whip-shaped distal end and a rod-shaped ventral bar with hatchet-shaped lateral ends. Bicentenariella sinuosa n. sp. is typified by possessing a MCO with an irregular filamentous membrane surrounding its shaft and a dumbbell-shaped ventral bar. Bicentenariella puertopizarroensis n. sp. can be differentiated from its congeners by having a tubular-shaped MCO with twisted distal end and a narrow W-shaped ventral bar. Parancylodiscoides peruensis Cruces, Chero, Sáez & Luque, 2017 from Hemanthias peruanus (Steindachner) and P. signiferi Cruces, Chero, Sáez & Luque, 2017 from H. signifer (Garman), are transferred to Bicentenariella n. g. as B. peruensis n. comb and B. signiferi n. comb., respectively.

New arrangement of three genera of fish tapeworms (Cestoda: Proteocephalidae) in catfishes (Siluriformes) from the Neotropical Region: taxonomic implications of molecular phylogenetic analyses.

Tapeworms (Cestoda: Proteocephalidae) are the dominant component of communities of intestinal parasites in pimelodid and other catfishes (Siluriformes) from South America. Even though these parasites have been studied intensively over more than one century, molecular taxonomy and phylogenetics have questioned their morphology-based classification, thus raising doubts about the systematic value of traits commonly used to circumscribe individual taxa. In the present study, members of three morphologically well-characterized genera of proteocephalids from pimelodid (Hemisorubim platyrhynchos and Sorubim lima) and auchenipterid (Ageneiosus inermis) catfishes from the Paraná or Amazon River basins were subjected to DNA sequencing of the large subunit nuclear ribosomal RNA (lsrDNA) and complete mitochondrial cytochrome c oxidase subunit I (COI). Phylogenetic analyses revealed the sister relationship between Manaosia bracodemoca and Mariauxiella piscatorum, and among Mariauxiella pimelodi and Ageneiella brevifilis. As a result, Mar. piscatorum and A. brevifilis are transferred to Manaosia and Mariauxiella, respectively, as Manaosia piscatorum n. comb. and Mariauxiella brevifilis n. comb., and the genus Ageneiella is suppressed. Diagnoses of Manaosia and Mariauxiella are amended. In addition, the present study revealed misidentification of tapeworms whose sequences are deposited in the GenBank database.

First Data on the Parasites of the Pacific Kingcroaker Menticirrhus elongatus (Perciformes: Sciaenidae): Description of a New Species of Rhamnocercoides (Dactylogyridea: Diplectanidae).

INTRODUCTION: A new monogenean, Rhamnocercoides lambayequensis n. sp. (Dactylogyridea: Diplectanidae), is described based on the specimens collected from the gills of the Pacific kingcroaker Menticirrhus elongatus (Günther 1864) (Perciformes: Sciaenidae), a demersal fish endemic to Eastern Pacific, captured off the South American Pacific coast, Lambayeque Region, Peru. MATERIALS AND METHODS: Monogeneans were fixed in hot 4% formalin. Some monogeneans were transferred directly onto a slide in a drop of glycerin-ammonium picrate mixture (GAP). Others were mounted stained with Gomori's trichrome in Canada balsam. Drawings were made using of a drawing tube. RESULTS: The new species is mainly characterized by its MCO, which is tubular and straight, with external (distally expanded and bifurcated) and internal tubes (distally uncovered by external tube). Rhamnocercoides lambayequensis n. sp. is also characterized by having the following features: a weakly sclerotized almost pyriform vagina; haptoral acicular spines with expanded distal portion and by having a small group of haptoral accessory spines associated with haptoral lobes arranged as spikes. CONCLUSIONS: This is the first data on the parasites of M. elongatus, a little known, but popular fish in local markets. The present finding brings to two, the number of known species of Rhamnocercoides Luque and Iannacone 1991, and represents the sixth described marine diplectanid species infecting sciaenid fishes from Peru.

An integrative approach assesses the intraspecific variations of Procamallanus (Spirocamallanus) inopinatus, a common parasite in Neotropical freshwater fishes, and the phylogenetic patterns of Camallanidae.

Integrative taxonomy was used to evaluate two component populations of Procamallanus (Spirocamallanus) inopinatus in Brazil and the phylogeny Camallanidae. Parasite populations were collected in the characiform Anostomoides passionis from River Xingu (Amazon basin) and Megaleporinus elongatus from River Miranda (Paraguay basin). Morphology was analysed using light and scanning electron microscopy (SEM). Genetic characterization was based on partial sequences of the 18S and 28S rDNA, and COI mtDNA. Phylogenies were based on 18S and COI due to data availability. Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (PTP) and *BEAST were used for species delimitation and validation. SEM revealed for the first time the presence of minute denticles and pore-like structures surrounding the oral opening, phasmids in females and confirmed other important morphological aspects. Statistical comparison between the two-component populations indicated morphometric variations, especially among males. The different component population of P. (S.) inopinatus showed variable morphometry, but uniform morphology and were validated as conspecific by the GMYC, PTP and *BEAST. Some camallanid sequences in GenBank have incorrect taxonomic labelling. Host, environment and geographic aspects seem to be related to some lineages within Camallanidae; however, their real phylogenetic meanings are still unclear.

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.

Testing for deterministic succession in metazoan parasite communities of marine fish.

Parasite communities are similar to free-living communities; decay of similarity over geographic distance, theory of island biogeography, species-area relationships and nestedness have been documented in both communities. Ecological succession has been studied in free-living communities but has rarely been examined in parasite communities. We use seriation with replication to test the hypothesis that succession of parasite community structure is deterministic, thus developing throughout consecutive changes along the fish ontogeny, via a seriated pattern. 12 306 marine fishes (95 species) were studied. In 40 species, a seriated pattern was detected; 25 had a tendency towards a seriated pattern, and for 31 species, succession was at random. Age-classes for each host species explained deterministic successional patterns for whole parasite communities and ectoparasites. Richness and number of age-classes explained this pattern for endoparasites. Seriated successional pattern was evident for parasite communities of long-lived marine fish, indicating that parasite communities follow sequential changes over time, like many free-living communities.

A new genus and three new species of dactylogyrids (Monogenea), gill parasites of the threadfin bass, Pronotogrammus multifasciatus Gill (Perciformes: Serranidae) in the Southeastern Pacific Ocean off Peru.

Pronotogrammella n. g. is erected to accommodate Pronotogrammella boegeri n. sp. (type-species), Pr. scholzi n. sp. and Pr. multifasciatus n. sp. (Monogenea: Dactylogyridae). The new species are gill parasites of the threadfin bass Pronotogrammus multifasciatus Gill (Perciformes: Serranidae), a demersal teleost collected from off the coastal zone of Puerto Pizarro, Tumbes, Peru. Pronotogrammella n. g. is mainly characterised by having broadly fork-shaped dorsal anchors, which have an accessory anchor sclerite articulated to the tip of the superficial roots. Pronotogrammella n. g. is also characterised by having: (i) a tubular tapered-shaped male copulatory organ (MCO), filamentous distally, with a clockwise coil at distal end or not, lacking accessory piece; (ii) a dorsal bar with an anteromedial delicate umbelliform membrane supported by two processes; (iii) hooks with upright blunt thumb and uniform shank; (iv) a vaginal aperture dextrolateral; (v) a subquadrangular haptor, with inconspicuous lateral flaps and lacking haptoral reservoirs; and (vi) eye-spot or chromatic granules absent. Pronotogrammella boegeri n. sp. is characterised by its crosier-shaped MCO having a clockwise coil at distal end and by its dorsal bar with a straight anteromedial processes. Pronotogrammella scholzi n. sp. is typified by possessing of a dorsal bar with the anteromedial processes like cow horns, hoof-shaped deep roots of the dorsal anchors and a broader shaft of the MCO. Pronotogrammella multifasciatus n. sp. differs from all congeners by having a tubular MCO with twisted shaft and a base with a short and broad arm and by having an almost dumbbell-shaped ventral bar.

Redescription and First Nucleotide Sequences of Rhinobatonchocotyle pacifica Oliva & Luque, 1995 (Monogenea: Hexabothriidae), a Parasite of Pseudobatos planiceps (Garman, 1880) (Rhinopristiformes: Rhinobatidae) from Peru.

INTRODUCTION: Specimens of Rhinobatonchocotyle pacifica Oliva & Luque, 1995 (Hexabothriidae) were collected from the gill filaments of Pacific guitarfish, Pseudobatos planiceps (Garman, 1880) (Rhinopristiformes: Rhinobatidae), from off the coast of Chorrillos, Lima, Peru. Since the original description of R. pacifica was incomplete, we herein redescribe R. pacifica based on re-examination of the holotype, paratypes, and newly collected voucher specimens. Nucleotide sequences (18S, 28S) for R. pacifica are presented for the first time, and a phylogenetic analysis conducted. MATERIALS AND METHODS: Monogeneans were examined with light microscopy and partial sequences of 18S and 28S rDNA genes were obtained. RESULTS: The following taxonomically important morphological features are described: presence of seminal receptacle, spiniform papillae within oral cavity, haptoral sucker sclerites and anchors, hook surface striations, muscular pad associated with each haptoral sucker sclerite (except sclerite 1), muscular bulbs in appendix suckers, and oötype lacking longitudinal rows of large cells (oötype not côtelé). The genital complex is detailed. The diagnosis of Rhinobatonchocotyle is emended to include species with or without seminal receptacle. Representative nucleotide sequences of partial 18S and 28S rDNA genes of R. pacifica were obtained for the first time and used for reconstructing the phylogeny of Hexabothriidae. CONCLUSION: The phylogenetic reconstruction confirmed the species within the Hexabothriidae.

The phylogenetic position of Anacanthorus (Monogenea, Dactylogyridae) parasitizing Brazilian serrasalmids (Characiformes).

Anacanthorus (Anacanthorinae) is one of the most speciose and common genera of neotropical monogeneans, yet there are still many gaps in our knowledge concerning their diversity and phylogeny. We performed phylogenetic analyses of molecular sequences in order to investigate the phylogenetic position within the Dactylogyridae of Anacanthorus spp. infesting serrasalmids from two Brazilian river basins. Sequences of partial 28S rDNA obtained for nine species of Anacanthorus and Mymarothecium viatorum parasitizing serrasalmids and the published sequences of other members of the Dactylogyridae were included in the phylogenetic reconstruction. Phylogenetic analyses supported the monophyly of anacanthorine monogeneans. The Anacanthorinae (represented in this study by Anacanthorus spp.) formed a monophyletic group included in a large clade together with a group of solely freshwater Ancyrocephalinae and species of the Ancylodiscoidinae. Mymarothecium viatorum (Ancyrocephalinae) was placed within the clade of freshwater Ancyrocephalinae. The phylogenetic analyses indicated that the relationships among species of Anacanthorus reflect those of their serrasalmid hosts: the first subgroup includes a species specific to hosts assigned to Piaractus, a member of the "pacus" lineage; the second subgroup includes a species parasitizing the "Myleus-like pacus" lineage; and the third subgroup includes species parasitizing the lineage of the "true piranhas". We suggest that Anacanthorus and their serrasalmid hosts can be considered a useful model to assess host-parasite biogeography and coevolution in the neotropics. However, future studies focusing on a wider spectrum of host species and their specific Anacanthorus spp. are needed in order to investigate coevolution in this highly diversified system.

New Species and Records of Anacanthorus (Monogenea: Dactylogyridae) Parasitizing Serrasalmid Fish (Characiformes) from Brazil, Including Molecular Data.

INTRODUCTION: Species of the genus Anacanthorus Mizelle & Price, 1965 represent commonly known parasites of Neotropical Characiformes. Anacanthorus is one of the most specious Neotropical monogenean genus, currently comprising 73 nominal species. MATERIALS AND METHODS: Fish were obtained from the Miranda River, Mato Grosso do Sul, from the Xingu River, Pará, from the Mogi Guaçu River, São Paulo and from the Upper Parana River, Paraná, Brazil. The monogeneans found were examined in a light microscope and partial sequences of the mitochondrial cytochrome c oxidase 1 gene were obtained for most species. RESULTS: Two new species of Anacanthorus were retrieved from Brazilian serrasalmids and are described herein. Anacanthorus paraxaniophallus n. sp. from Serrasalmus maculatus Kner has great similarity to A. xaniophallus Kritsky et al. (J Helminthol Soc Wash 59:25-51, 1992) by the general morphology of the copulatory complex, but it can be easily differentiated by a larger accessory piece with a slightly curved point, by having a basal flap in the male copulatory organ and by the morphology of hooks, with flattened thumb. Anacanthorus myleusi n. sp. from Myloplus schomburgkii (Jardine) is mainly distinguished by its unique copulatory complex, possessing an inverted J-shaped MCO with terminal flare and a hook-shaped accessory piece. Additionally, new host records are provided to A. lepyrophallus, geographical records are provided to four species of Anacanthorus (A. lepyrophallus, A. maltai, A. sciponophallus and A. thatcheri), which are being recorded in the Paraná River basin for the first time, and we also provide molecular data for six species of Anacanthorus.

Four new species of dactylogyrids (Monogenea: Dactylogyridae) parasitic on gills of labrid and sparid fishes from Southeastern Pacific Ocean off Peru.

During a research on gill ectoparasites of Peruvian marine fishes, four dactylogyrid (Monogenea) species, parasitising two teleost species, Bodianus diplotaenia (Gill) (Labridae) and Calamus brachysomus (Lockington) (Sparidae), were found. Euryhaliotrema luisae n. sp. ex C. brachysomus is differentiated from other congeneric species by the morphology of the male copulatory organ, which comprises a coil of nine counterclockwise rings, and by the morphology of the anchors and bars. Euryhaliotrema magnopharyngis n. sp. ex C. brachysomus can be distinguished from all other congeners by having a well-developed pharynx occupying much of the anterior region and by the ventral bar, which is V-shaped, with well-elongated, thin arms. In addition, E. luisae n. sp. and E. magnopharyngis n. sp. can be differentiated from all other members of Euryhaliotrema Kritsky & Boeger, 2002 by the presence of a glandular oval plate lying on peduncle. Haliotrema diplotaenia n. sp. ex B. diplotaenia is characterised by the structure of the male copulatory organ, comprising a tapered-shaped cirrus tube with twisted acute tip and a filament-shaped accessory piece with medial and distal expansions, and by the morphology of the ventral bar (inverted W-shaped, with short lateral ends and two anterior conical protuberances). Haliotrema saezae n. sp. ex B. diplotaenia differs from all other members of Haliotrema Johnston & Tiegs, 1922 by having a tubular copulatory organ with curved distal tip and a filament-shaped accessory piece without lateral expansions, and by the morphology of anchors and bars. The present findings are added to the other six marine dactylogyrids previously reported from Peru.

Phylogenetic Position of Pseudosellacotyla lutzi (Freitas, 1941) (Digenea: Cryptogonimidae), A Parasite of Hoplias malabaricus (Bloch) in South America, through 28S rDNA Sequences, and New Observations of the Ultrastructure of Their Tegument.

The freshwater fish digenean Pseudosellacotyla lutzi ( Freitas, 1941 ) Yamaguti, 1954 has had an unsettled taxonomic history, and has at various times been classified as a member of Nanophyetidae, Heterophyidae, Microphallidae, Faustulidae, and Cryptogonimidae. Nine individual specimens of the trahira, Hoplias malabaricus (Bloch, 1794), were sampled in the Paraná River basin, Paraná State, Brazil; 22 specimens of P. lutzi were collected. One specimen of P. lutzi was used to obtain a sequence of the domains D1-D3 of the 28S rRNA gene, and to perform a phylogenetic analysis to assess their position and classification within Plagiorchiida. The resulting tree unequivocally shows that the species, along with acanthostomines, belong to the Cryptogonimidae, corroborating recent findings based on the morphology of the cercariae, and in the characteristics of the life cycle. In addition, the study of the ultrastructure of the tegumental spines through scanning electron microscopy allowed us to characterize them as pectinate spines possessing 3 to 8 digitiform projections at their distal end and extending from the anterior to the posterior extremity of the body. This study also provides the first molecular data for a cryptogonimid from South America.

Morphological and phylogenetic characterization of a novel Unicauda species, infecting the kidney of Astyanax altiparanae (Teleostei: Characidae) in Brazil.

During a parasitological survey of Astyanax altiparanae captured in the Mogi Guaçú river, Pirassununga, state of São Paulo, Brazil, a new species of myxozoa was observed infecting the kidney of 30 of 42 specimens. Plasmodia of the new myxozoa, referred to herein as Unicauda whippsi n. sp. were spherical and varied from 450 to 1000 µm in length. The mature spore was elongated and measured 11 ± 1.2 (10-12) µm long by 5.4 ± 0.6 (4.7-7.2) µm wide. Polar capsules of unequal length with the filament coiled 7-9 times and a unique caudal process characteristic of the genus Unicauda, were recorded. Phylogenetic analysis demonstrated that U. whippsi n. sp. clustered with members of the genus Unicauda and Myxobolus, confirming it's placement within the family Myxobolidae. This is the first record of a species of Unicauda infecting characiform fish, as well as the first registered occurrence of species of this genus in South America.

Hypanocotyle bullardi n. gen. n. sp. (Monogenea: Hexabothriidae) from gill of the diamond stingray Hypanus dipterurus (Jordan et Gilbert) (Myliobatiformes: Dasyatidae) in the Southeastern Pacific Ocean off Peru.

A new genus and species of monogenean belonging to Hexabothriidae, Hypanocotyle bullardi n. gen. n. sp., is described based on specimens collected from the gill filaments of the diamond stingray, Hypanus dipterurus (Jordan et Gilbert) (Myliobatiformes: Dasyatidae), a demersal chondrichthyan collected off the coast of Callao, Peru. Hypanocotyle n. gen. has the following combination of diagnostic features that differentiate it from other hexabothriid genera: haptor symmetrical; vasa efferentia having proximal (narrow, with thin glandular wall) and distal (expanded, interlaced, with thick glandular wall) portions, joining medially to form vas deferens; vas deferens having proximal (expanded, sinuous, with thick glandular wall) and distal (narrow, strongly sinuous, with thin glandular wall) portions; male copulatory organ unarmed, proximal portion slightly sinuous and tube-like, distal portion funnel-shaped; prostatic glands present, distributed around of the MCO; seminal receptacle present; ootype lacking longitudinal rows of large cells (no oötype côtelé); vaginae parallel, with well-differentiated proximal (glandular, narrow, tube-like, slightly sinuous) and distal (musculoglandular, convoluted) portions; gland cells surrounding the vaginal duct along the entire length of distal portion, densely clustered in middle portion; uterine eggs with 2 elongate filaments. Phylogenetic reconstructions by maximum-likelihood method, based on newly obtained partial 18S and 28S sequences, shows that H. bullardi n. gen. is included within the family Hexabothriidae, order Diclybothriidea. This is the second hexabothriid genus recorded from a diamond stingray (Dasyatidae), and the fourth hexabothriid species recorded from Peru. A key to hexabothriid genera is provided.

Towards a robust systematic baseline of Neotropical fish tapeworms (Cestoda: Proteocephalidae): amended diagnoses of two genera from the redtail catfish, Phractocephalus hemioliopterus.

Species of two monotypic genera, Ephedrocephalus Diesing, 1850 and Zygobothrium Diesing, 1850 (Cestoda: Proteocephalidae), parasites of one of the most basal members of the catfish family Pimelodidae, the redtail catfish, Phractocephalus hemioliopterus, in the Neotropical Region, are redescribed based on the evaluation of type specimens and newly collected material. Generic diagnoses are amended to provide a robust baseline for the future re-arrangement of the classification of proteocephalid cestodes. Ephedrocephalus is typified by the medullary position of the ovary and uterus, the cortical distribution of vitelline follicles (dispersed throughout almost the entire ventral cortex) and the testes in one dorsal field. Zygobothrium is primarily characterized by its possession of a robust scolex bearing four uniloculate suckers with two openings each and by the tetralobed velum (laciniations) on every proglottid (two on the ventral and two on the dorsal side). The redtail catfish is the definitive host of as many as seven species of proteocephalid cestodes, which, however, do not represent a monophyletic group. Some species, including Z. megacephalum, are among the earliest diverged parasites of Neotropical catfishes, being closely related to African and North American proteocephalids from catfishes, whereas others such as E. microcephalus belong to more recently diverged taxa with uncertain interrelations. Unlike most proteocephalids of the redtail catfish, which almost always infect the anterior parts of the host intestine, E. microcephalus and Z. megacephalum occur exclusively in its posterior third. A key to the identification of the proteocephalid species parasitizing P. hemioliopterus is also presented.