A new species of Aplectana Railliet & Henry, 1916 (Nematoda: Cosmocercidae) in the Brazilian Amazon and the taxonomic status of Aplectana longa.

Nematodes of the genus Aplectana Railliet & Henry, 1916 are common parasites of the digestive tract of amphibians and reptiles in the Neotropical region. During a parasite survey on Boana boans (Linnaeus, 1758), we found specimens of nematodes with Aplectana characteristics. We observed a set of characteristics that differs the species of our study from its congeners, and the present study describes a new species of Aplectana parasite of B. boans using light microscopy and scanning electron microscopy. Aplectana pella n. sp. has lateral alae and somatic papillae in males and females; males have equal short spicules, and the gubernaculum is absent. The arrangement of pairs of caudal papillae also differs from other species (2 precloacal,1 adcloacal, and 5 postcloacal+1 unpaired). In females, the vulva is simple, with non-prominent lips, and equatorial. This is the first record of the genus Aplectana parasitizing B. boans and the 58th species described for this genus. Additionally, we added the precloacal papillae pattern of A. delirae, and based on morphological and morphometric characteristics, we propose the reallocation of Aplectana longa to the genus Oxyascaris.

New species of Serpinema (Nematoda: Camallanidae) from the scorpion mud turtle Kinosternon scorpioides (Testudines: Kinosternidae) from eastern Amazon, Brazil.

The genus Serpinema Yeh, 1960 allocates parasitic nematodes of freshwater turtles distributed across the Oriental, Neotropical, and Palearctic regions. Five of 10 valid species of the genus Serpinema occur in the Neotropical region, and three have been recorded parasitizing Kinosternon scorpioides Linnaeus, 1766. In the present work, we describe a new species of Serpinema, a gastrointestinal parasite of K. scorpioides from the Brazilian Amazon, using light and scanning electron microscopy. Serpinema pelliculatus n. sp. differs from other species of the genus by the number and distribution of caudal papillae and spicule morphology. The new species is the seventh recorded for the Neotropical region.

"Revisiting the past": a redescription of Physaloptera retusa (Nemata, Physalopteridae) from material deposited in museums and new material from Amazon lizards.

Physaloptera Rudolphi, 1819 is a genus of nematodes that includes approximately 100 species parasitic in vertebrates around the world. From these, approximately 30 occur in the Neotropical region, with nine reported from neotropical reptiles. Physaloptera spp. are recognized by their distinct morphology of the apical end and characters of the reproductive system. However, despite the fact that the morphological characters for species diagnosis have been firmly established, we frequently find identification problems regarding poorly detailed descriptions and poorly preserved specimens. These may lead to taxonomic incongruencies. Physaloptera retusa (Rudolphi, 1819) is the most common species of the genus and has been reported from several species of neotropical reptiles. Based on our reexaminations of nematode specimens identified as P. retusa from different museum collections, we provide a detailed redescription including the type material, voucher specimens and new specimens recovered currently and showed in this study with new morphological data obtained using light and scanning electron microscopy tools.

Morphological and molecular characterization of Cosmocercoides amapari n. sp. (Nematoda: Cosmocercidae), parasitic in hylid frogs from the Brazilian Amazon.

Cosmocercoides Wilkie, 1930 are gastrointestinal parasites commonly found in amphibians and reptiles, with 4 species reported from the Neotropical region. In the present study, a new species of Cosmocercoides, namely Cosmocercoides amapari n. sp. is described using integrated approaches such as light and scanning microscopy, and DNA sequencing of the mitochondrial cytochrome c oxidase subunit 1 gene. The specimens were collected from the large intestine of 3 species of hylid frogs in Amapá, Brazil. The new species can be distinguished from its congeners by morphological traits, including the pattern of caudal papillae, absence of the gubernaculum, 2 poorly sclerotized spicules, presence of lateral alae and somatic papillae along the body. In addition, our molecular analyses and phylogenetic reconstructions strongly support the status of the new taxon, which clustered poorly with a large clade of Cosmocerca spp. Cosmocercoides amapari n. sp. is the 29th species of the genus, the 5th from the Neotropical region, the third reported in Brazil, the second described from the Amazon region and the first belonging to the Neotropical region with molecular data.

Vogtnema asymmetrica n. gen., n. sp. (Nematoda: Cosmocercoidea: Atractidae) parasite of Rhinoclemmys punctularia (Daudin) (Testudines: Geoemydidae) from eastern Amazon, Brazil.

Nematodes collected from the stomach and large intestine of Rhinoclemmys punctularia (Daudin) from the eastern Amazon, Brazil, are assigned to a new genus, Vogtnema n. gen., allocated in the family Atractidae (Cosmocerdoidea). Vogtnema n. gen. differs from all other genera of Atractidae based on the combination of the following morphological characters: four lips V-shaped (two subdorsal and two subventral) without sclerotized structures associated, absence of sclerotized formations and/or pieces surrounding the oral opening, oral aperture surrounded by flange internal membranous structures; in males the larger spicule is alate. The type species Vogtnema asymmetrica n. gen., n. sp. has the five precloacal pairs of papillae situated on the right side of the body that are more prominent than those on the left side. We also provide an identification key to the genera of the family Atractidae.

The natural interaction between Myotis nigricans (Schinz, 1821) and its trematodes: A histopathological analysis.

Bats have a wide diversity of digeneans; however, even with the recent increased interest in studies of parasites on these hosts, there are no data on the microscopic alterations of this host-parasite interaction. The present work characterizes and compares the histological aspects of the liver, gallbladder, and intestine of non-parasitized and parasitized Myotis nigricans by digeneans. Ten specimens of Myotis nigricans collected in an urban area of Western Amazonia were analyzed for parasites. The digeneans were removed from the hosts and identified. Tissue samples of the liver, gallbladder, and intestines of parasitized and non-parasitized hosts were collected for histological studies. The gallbladder was observed in repletion and presents mucosa formed by simple epithelium that varies from cubic to cylindrical. The hepatic lobes do not have a classic polyhedral-hexagonal aspect. Variations in basophilia, acidophile, and cytoplasmatic granulations were observed in hepatocytes. The parasitism of the intestinal digeneans was restricted to space delimited by the extensions of villi in high association with the intestinal epithelium, not invading the region of the intestinal glands at the base of the villi. Trematodes maintained attached to the villus by the oral sucker and acetabulum, connected by a "pleat" composed of epithelium and lamina propria layers. We observed no signs of inflammatory processes and cellular defense infiltrates in host tissues. Cytochemistry alterations, size variation, and granular deposits in hepatocytes, enterocytes, and goblet cells were observed. Thus, this report is the first study of the natural parasite-host interaction in the liver, gallbladder, and intestine in M. nigricans in the neotropical region.

New species of Parapharyngodon (Nematoda: Pharyngodonidae) parasite of Osteocephalus taurinus (Anura: Hylidae) from Northern Brazilian Amazon Region.

Parapharyngodon spp. are nematodes parasites of amphibian and reptiles worldwide distributed. Of 55 valid species, only 11 are known for the Neotropical realm, and six were found parasitizing hylid frogs in the world. In the present work, we describe a new species of Parapharyngodon from the large intestine of Osteocephalus taurinus from Reserva de Desenvolvimento Mamirauá, Amazonas, Brazil, using light and scanning electron microscopy. Parapharyngodon curupira n. sp. is allocated to the group of species with three pairs of cloacal papillae. However, it shows a set of different morphological characters compared to its congeners. In the new species, males have gubernaculum and smooth cloacal lip, females have pre-bulbar ovaries, and we also observed some morphometric differences. Among Parapharyngodon spp. from the Neotropical realm, the new taxon resembles P. alverangai and P. politoedi. The last species was described from the same host and biome (Amazon); however, they can be easily distinguished from new species by the presence of gubernaculum and v-shape structure at the lower caudal lip. Thus, we characterize and propose a new species of Parapharyngodon from the western amazon.

Phylogenetic relationships of Ochoterenatrema Caballero, 1943 (Digenea: Lecithodendriidae) with descriptions of two new species.

Ochoterenatrema is a small genus of lecithodendriid digeneans that includes six species parasitic in Neotropical bats in North and South America. Members of this genus are characterized by the presence of a pseudogonotyl formed by thickened tegument on the left side of the ventral sucker. We examined morphology of specimens belonging to five species of Ochoterenatrema from Brazil, Ecuador and the USA and describe two new Ochoterenatrema spp. (Ochoterenatrema sphaerula n. sp. and Ochoterenatrema gracilis n. sp.). These new species are readily differentiated from their congeners by a combination of morphological characters, including the distribution of vitelline follicles and the body shape. We have provided the first DNA sequences for Ochoterenatrema. Newly generated partial nuclear 28S rDNA and mitochondrial cox1 gene sequences were used to differentiate among species and study the phylogenetic affinities of Ochoterenatrema spp., including one of the new species, O. gracilis n. sp., as well as Ochoterenatrema diminutum, Ochoterenatrema fraternum and Ochoterenatrema cf. labda. The phylogeny of the Microphalloidea based on 28S had well-supported topology, particularly at the family level. The Ochoterenatrema clade was strongly supported; however, the internal topology of the clade was weakly supported. Comparison of sequences revealed 0.4-1.3% interspecific divergence in 28S and 9.1-19.7% interspecific divergence in cox1 among Ochoterenatrema spp. We hypothesize that extremely diverse fauna of bats in South and Central America harbors multiple undescribed species of Ochoterenatrema. Several lecithodendriid genera from bats and other hosts are yet to be included in future molecular phylogenetic analyses to test the monophyly of this extremely diverse digenean family and analyze evolutionary affinities of its constituent taxa.

A new species of Rhabdias (Nematoda: Rhabdiasidae), a lung parasite of Pristimantis chiastonotus (Anura: Strabomantidae) from the Brazilian Amazon: description and phylogenetic analyses.

Rhabdias Stiles and Hassal, 1905 comprises approximately 90 species of parasitic lung nematodes of amphibians and reptiles that have a wide distribution, with 21 species occurring in the Neotropics. In the present study, we describe Rhabdias waiapi n. sp. found parasitizing the lungs of the anuran species Pristimantis chiastonotus from the Amazon Biome in the Amapá State, Northern Brazil. The new species is characterized by having an elongated body, expansions of the cuticular inflation in the anterior end that become more discrete along the body, an anterior end with a slight constriction at the level of the esophageal apex with four rounded subapical elevations of the body wall, six lips, four near the edge of the oral opening and two more distant lateral ones, and a gradually tapering elongated tail. In addition, molecular analyses and phylogenetic reconstructions were made, with sequences from the coding region of the mitochondrial cytochrome c oxidase subunit I gene. Those results strongly support the status of the new taxon, which formed a poorly supported clade with Rhabdias sp. 5 from Anolis brasiliensis from Northeast Brazil. Rhabdias waiapi n. sp. is the 19th species of the genus described in the Neotropics for amphibians, the 10th in Brazil, the second described from hosts of the family Strabomantidae from the Neotropical region, and the first amphibian nematode species described in the Amapá State.

A NEW SPECIES OF ALLINTOSHIUS (NEMATODA: HELIGMOSOMOIDEA) FROM TWO SPECIES OF BATS IN BRAZIL.

Allintoshius Chitwood, 1937 is the only genus of the family Ornithostrongylidae (Travassos, 1937) Durette-Desset and Chabaud, 1981 that parasitizes bats. Currently, there are 10 valid species in the genus, of which 3 were described from Brazil. This study describes a new species of Allintoshius and records the first occurrence of a nematode of this genus parasitizing Artibeus lituratus (Olfers). Allintoshius gomesae n. sp. is characterized by having anterior region coiled, cephalic vesicle with cuticular dilation striated transversely, and claviform esophagus. Synlophe in females consists of 16 cuticular ridges at the mid-body. Males have large caudal bursa, and conic and small spicules, and the gubernaculum is absent. Females have uterus didelphic, amphidelphic, tail tip tapered, and ovijector divided into 2 divergent branches, subequal in length. The new species differs from its congeners especially by the shape of the tail tip, vulvar opening, and size of spicules. Allintoshius gomesae is the fourth species of Allintoshius from Brazil and the first report in Ar. lituratus, increasing the number of species recognized of the genus.

HELMINTH FAUNA OF THECADACTYLUS RAPICAUDA (HOUTTUYN, 1782) (SQUAMATA, PHYLLODACTYLIDAE) IN THE CAXIUANÃ NATIONAL FOREST, FROM THE BRAZILIAN EASTERN AMAZON.

The Amazon region is an important region for biodiversity, and many new species are described for this region each year. However, the diversity of parasites infecting Amazonian reptiles is still poorly known, and there are few studies about how parasite communities of these hosts are structured. Our study was designed to elucidate the parasite community structure of Thecadactylus rapicauda, one of the largest species of gekkonid lizards in the world, and to discover the relative utility of size, sex, and body mass of Thecadactylus rapicauda as predictive factors of the abundance of helminth parasites. We analyzed 40 individuals of T. rapicauda, of which 34 had parasites (85% of prevalence), with 269 specimens allocated to 10 species. Body size of the host showed a positive influence on the abundance of helminths. Host sex is another important factor related to the abundance of nematodes: females were usually heavily infected. We conclude that T. rapicauda has a high richness of the helminth species and that most of the species found infecting this host were nematodes with a direct life cycle. Additionally, we found new helminth species, which should be described formally in the future.

Do host habitat use and cospeciation matter in the evolution of Oswaldocruzia (Nematoda, Molineidae) from neotropical amphibians?

The genus Oswaldocruzia Travassos, 1917 includes approximately 90 species that are parasitic on amphibians and reptiles around the world, of which 43 occur in the neotropical region. However, molecular data supporting the taxonomic status of most species of the genus are scarce, and their phylogenetic relationships remain unknown. Using specimens of four molineid taxa (Oswaldocruzia belenensis Santos, Giese, Maldonado Jr. and Lanfredi, 2008; Oswaldocruzia chabaudi Ben Slimane & Durette-Desset, 1996, Oswaldocruzia chambrieri Ben Slimane & Durette-Desset, 1996 and Kentropyxia hylae Feitosa, Furtado, Santos and Melo, 2015) from amphibian hosts collected in different regions of Pará, Brazil, we conducted morphological studies, molecular analyses and phylogenies (maximum likelihood and Bayesian inference) using the cytochrome c oxidase subunity I (Cox1) gene. The newly generated sequences were compared with those of ten publicly available Cox1 sequences of Oswaldocruzia from Mexico. Our findings demonstrated significant differences between the sequences of amazonian specimens and sequences from specimens collected in Mexico, and we suggest that host-parasite cospeciation or habitat use might be related to molineid evolution in amphibian hosts. Additionally, this work presents new hosts and new geographical records for species of Oswaldocruzia from the neotropics.

Morphological diagnosis of Setaria labiatopapillosa in domestic bovids from Marajó Island, Brazil.

The genus Setaria is known worldwide for parasiting wild and domestic mammals, with 43 species registered, of which five occur in the American continent. The objective of this study was to characterize the occurrence, morphology and morphometry of S. labiatopapillosa in B. taurus and B. bubalis in Marajó Island, Brazil. Carcass inspections of 420 cattle were carried out in two slaughterhouses in Pará. The nematodes were found on the white and serous viscera of the small intestine, being cleaned and discussed for analysis by light microscopy and scanning electron microscopy. The morphological and morphometric characteristics are compatible with S. labiatopapillosa parasitizing both species, with a prevalence of 25% (B. bubalis) and 24% (B. taurus). Information obtained by scanning electron microscopy was added to the description of the species, in addition to expanding the distribution of this parasite in the national territory.

Interrelationships of Anenterotrema (Digenea: Dicrocoeliidae) from Neotropical bats (Mammalia: Chiroptera) with description of a new species from Molossus molossus in Brazil.

Anenterotrema is a small genus of dicrocoeliids (Digenea: Dicrocoeliidae) containing 6 species found in Neotropical bats. Members of this genus are characterized by the lack of digestive system organs and, unlike the majority of dicrocoeliids, parasitize the intestine of their definitive hosts. In this study, we have morphologically examined newly collected specimens belonging to four species of Anenterotrema from Brazil, Ecuador, and Panama. Based on the data in original descriptions and our analysis of quality new specimens, we resurrected Anenterotrema freitasi, previously synonymized with A. eduardocaballeroi. We also described a new species of Anenterotrema from Molossus molossus in the Brazilian Amazon. The new species differs from congeners in several morphological features, most prominently in the size and structure of its highly muscular, protuberant ventral sucker. It is also characterized by the lack of the semi-circular thickening of the tegument around the oral sucker typical for some members of the genus. We used partial DNA sequences of the large ribosomal subunit gene (28S) and mitochondrial cytochrome c oxidase subunit 1 gene (cox1) to test the monophyly of Anenterotrema, and study the interrelationships and determine the inter- and intraspecific variation of three Anenterotrema spp. collected from different bat species in Brazil, Ecuador and Panama.

A New Species of Cosmocercoides (Ascaridida: Cosmocercidae) Parasitic in Tree Frogs from Southern Amazonia.

Cosmocercoides meridionalis n. sp. is described from the large and small intestines of 5 species of tree frogs belonging to the families Hylidae and Phyllomedusidae collected from 2 localities in Southern Amazonia. The new species is allocated to the genus Cosmocercoides Wilkie, 1930, due to the presence of papillae in rosettes, which are complex caudal papillae surrounded by punctuations. Cosmocercoides meridionalis n. sp. differs from its congeners by a combination of the following characters: the absence of the gubernaculum, the total length of the female (twice the size of the male), and the presence of 26 rosette papillae with a unique arrangement and distribution pattern: 11 pre-cloacal pairs, 1 ad-cloacal pair, and 1 post-cloacal pair. This is the first species of the genus described from the Amazonia region.

A new species of Metadelphis Travassos, 1944 (Digenea: Dicrocoeliidae) from the gall-bladder of Molossus molossus (Pallas) (Chiroptera: Molossidae) in the Brazilian eastern Amazon.

Metadelphis tkachi n. sp. is described based on material from the gall-bladder of Molossus molossus (Pallas) (Chiroptera: Molossidae) in the Brazilian eastern Amazon. The main differentiating characters of the new species include lobed, tandem testes and elongated clusters of vitelline follicles commencing at the level of the seminal receptacle. The new species can be distinguished from Metadelphis lenti (Santos & Gibson, 1998) and Metadelphis apharyngotrema (Marshall & Miller, 1979) by the shape and position of the testes; from Metadelphis evandroi Travassos, 1944 by having tandem, lobed testes and shorter clusters of vitelline follicles; from Metadelphis compactus Travassos, 1955 by having tandem testes and more elongated clusters of vitelline follicles, and from Metadelphis alverangai Travassos, 1955 by having smaller testes and body, and vitellarium with large follicles. New morphological data are reported for M. lenti based on light and scanning electron microscopy; intraspecific variation was observed.

Contracaecum larvae: morphological and morphometric retrospective analysis, biogeography and zoonotic risk in the amazon.

In Brazil there are several records of parasitic nematodes of fish with zoonotic potential, especially those belonging to the family Anisakidae. This study considers the morphology, morphometry and prevalence of Contracaecum in Astronotus ocellatus , fish consumed in the Amazon and sold as ornamental and it also performs a retrospective analysis of the diversity of fish with larvae of Contracaecum, in studies carried out in Brazil over a period of 90 years. 40 specimens of A. ocellatus were necropsied, and the nematodes were collected and fixed in 93 parts 70% ethyl alcohol, 5 parts formaldehyde, and 2 parts glacial acetic acid (AFA) for morphological analysis under light microscopy and scanning electron microscopy. Of the 40 fish collected during this work, 27 were parasitized by Contracaecum larvae with a total intensity of 150 larvae. Retrospective analysis of intermediate host diversity for Contracaecum larvae resulted in 16 orders, 49 families, 96 genera, 140 species and a hybrid morphotype. In the retrospective study, half of the fish were from freshwater, with the order Perciformes being the most representative, with 16 families, 30 genera and 37 species. In Brazil, the occurrence of larvae of Contracaecum in fish was reported in 15 of the 26 states, with Rio de Janeiro presenting the most information regarding fish harboring Contracaecum larvae.

Contracaecum larvae: morphological and morphometric retrospective analysis, biogeography and zoonotic risk in the amazon / Larva de Contracaecum: análise retrospectiva morfológica e morfométrica, biogeografia e risco zoonótico na amazônia

Abstract In Brazil there are several records of parasitic nematodes of fish with zoonotic potential, especially those belonging to the family Anisakidae. This study considers the morphology, morphometry and prevalence of Contracaecum in Astronotus ocellatus , fish consumed in the Amazon and sold as ornamental and it also performs a retrospective analysis of the diversity of fish with larvae of Contracaecum, in studies carried out in Brazil over a period of 90 years. 40 specimens of A. ocellatus were necropsied, and the nematodes were collected and fixed in 93 parts 70% ethyl alcohol, 5 parts formaldehyde, and 2 parts glacial acetic acid (AFA) for morphological analysis under light microscopy and scanning electron microscopy. Of the 40 fish collected during this work, 27 were parasitized by Contracaecum larvae with a total intensity of 150 larvae. Retrospective analysis of intermediate host diversity for Contracaecum larvae resulted in 16 orders, 49 families, 96 genera, 140 species and a hybrid morphotype. In the retrospective study, half of the fish were from freshwater, with the order Perciformes being the most representative, with 16 families, 30 genera and 37 species. In Brazil, the occurrence of larvae of Contracaecum in fish was reported in 15 of the 26 states, with Rio de Janeiro presenting the most information regarding fish harboring Contracaecum larvae.

Resumo No Brasil existem vários registros de nematóides parasitos de peixes com potencial zoonótico, especialmente aqueles pertencentes à família Anisakidae. Este estudo considera a morfologia, morfometria e prevalência de Contracaecum em Astronotus ocellatus, peixe consumido na Amazônia e vendido como ornamental, e também realiza uma análise retrospectiva da ictiofauna parasitada com larvas de Contracaecum, em estudos realizados no Brasil, durante um período de 90 anos. 40 espécimes de A. ocellatus foram necropsiados, e os nematóides foram coletados e fixados em 93 partes de álcool etílico 70%, 5 partes de formaldeído e 2 partes de ácido acético glacial (AFA) para análise morfológica em microscopia de luz e microscopia eletrônica de varredura. Dos 40 peixes coletados durante este trabalho, 27 estavam parasitados por Contracaecum, com intensidade total de 150 larvas. Análises retrospectivas da diversidade de hospedeiros intermediários para larvas de Contracaecum resultaram em 16 ordens, 49 famílias, 96 gêneros,140 espécies e um morfotipo híbrido. No estudo retrospectivo, metade dos peixes eram de água doce, sendo a ordem Perciformes a mais representativa, com 16 famílias, 30 gêneros e 37 espécies. No Brasil, a ocorrência de larvas de Contracaecum em peixes foi relatada em 15 dos 26 estados, com o Rio de Janeiro apresentando mais informações sobre peixes portadores de larvas de Contracaecum.

First report of filarial nematodes in free-living pitheciid primates.

Although little studied, infections with nematodes of the Onchocercidae Leiper, 1911, predominated by the genera Dipetalonema Diesing, 1861 and Mansonella Faust, 1929, are frequent in wild primates and human populations in the Neotropical forest areas. This study reports natural infections with Dipetalonema freitasi Bain, Diagne & Muller, 1987 and D. gracile (Rudolphi, 1809) in two free-living species of pitheciid primates, extending the known geographical distribution of these species to the forest of the Peruvian Amazon. Adult worms were recovered from the thoracic and abdominal cavities of two species of monkeys, Pithecia monachus monachus (É. Geoffroy Saint-Hilaire) and Cacajao calvus ucayalii (Thomas) (Primates: Pitheciidae), collected along the Yavari-Mirin River basin and analysed via light and scanning electron microscopy. Both host species represent new host records for D. freitasi and D. gracile. Morphometric data are also presented for the sampled filarial worms in addition to morphological details obtained through light and electron microscopy examination of D. freitasi specimens.

Cucullanus marajoara n. sp. (Nematoda: Cucullanidae), a parasite of Colomesus psittacus (Osteichthyes: Tetraodontiformes) in the Marajó, Brazil / Cucullanus marajoara n. sp. (Nematoda: Cucullanidae), um parasito de Colomesus psittacus (Osteichthyes: Tetraodontiformes) no Marajó, Brasil

Abstract Cucullanus marajoara n. sp. (Cucullanidae) is reported to parasitize Colomesus psittacus (Tetraodontiformes), which is a fish species from the Marajó Archipelago, state of Pará, estuarine region of the Brazilian Amazon. The new species differs from similar species by the presence of a protruding upper lip on the cloacal opening, the distribution of the cloacal papillae: five pre-cloacal papillae pairs and 5 are ventral and located posteriorly to the pre-cloacal sucker and an unpaired papilla is located on the upper cloacal lip and five post-cloacal pairs, and a pair of lateral phasmids located between papillae pairs. Additionally, Cucullanus marajoara n. sp. is compared to other species of this genus described in Brazil, particularly Cucullanus ageneiosus and Cucullanus oswaldocruzi, which both occur in the same zoogeographic region of this study but parasitize fish of a different order (Siluriformes). Cucullanus dodsworthi and Cucullanus brevicaudatus are the only described species parasitizing fish of the order Tetradontiformes in Brazil, and the new species differs from these species by the distribution of the cloacal papillae and the host habitat. The description of Cucullanus marajoara n. sp. adds data to the biodiversity of described parasites that parasitize Tetradontiformes of the estuarine ichthyofauna in the Brazilian Amazon.

Resumo Cucullanus marajoara n. sp. (Cucullanidae) é descrita parasitando Colomesus psittacus (Tetraodontiformes) peixe do arquipélago de Marajó, Estado do Pará, região estuarina da Amazônia brasileira. A nova espécie difere de seus congêneres por apresentar lábio superior da abertura cloacal protrudente e na distribuição de papilas cloacais: 5 pares pré-cloacais, e uma papila não pareada no lábio superior da cloaca e 5 pares pós-cloacais, um par de fasmídeos laterais. Além disso, Cucullanus marajoara n. sp. é comparada com outras espécies do gênero descritas no Brasil, em especial Cucullanus ageneiosus e Cucullanus oswaldocruzi, ambos parasitos de peixes da ordem Siluriformes; porém, ocorrendo na mesma região zoogeográfica deste estudo, diferem da ordem do hospedeiro da nova espécie (Tetraodontiformes). Cucullanus dodsworthi e Cucullanus brevicaudatus são as únicas espécies descritas parasitando peixe da ordem Tetradontiformes no Brasil, e a nova espécie difere dessas na distribuição das papilas cloacais e habitat dos hospedeiros. Cucullanus marajoara n. sp. adiciona dados a biodiversidade de parasitos descritos parasitando Tetradontiformes da ictiofauna estuarina da Amazônia brasileira.