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Purpose: The Myxozoa class is characterized by parasites that have valves joined by a suture line and polar capsules containing eversible spiral filamento and this class is considered an obligate parasite. The genus Ceratomyxa has approximately 300 species described in fish, both marine and freshwater fish, mainly infecting the gallbladder, but also occurring in the urinary bladder. This study describes a new species of Ceratomyxa in the Amazon region for Pimelodella cristata., Methods: For these analyses, the fish were desensitized by means of a medullary section with the aid of a sharp metallic instrument. With the fish desensitized, the entire body surface was examined under a binocular stereoscopic microscope. The gallbladder fragments were collected and fixed in Davidson for histological analyses and in ethanol for molecular analyses., Results: This parasite was found in the host's gallbladder, with elongated spores in a decreasing shape in sutural view, measuring 1.64 ± 0.6 μm in length and 17.13 ± 2.6 μm in width. The polar capsules had a spherical shape of equal size and measured 1.36 ± 0.17 μm in length and 0.9 ± 0.05 μm in width, and each polar capsule contained 4 to 5 turns., Conclusion: Morphological and phylogenetic analyzes denote that this is a new species of the genus Ceratomyxa., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The Amazon is the largest river basin in the world and it is home to the greatest diversity of freshwater fish in the world. Mesonauta festivus is a cichlid popularly known as flag cichlid, widely distributed throughout South America. The diversity of parasites in fish from the Amazon region is still underestimated, due to the high fishes diversity. The Myxozoa class has a universal distribution, with some specimens being pathogenic to some fish. The aim of this work was to describe a new species of Hoferellus in M. festivus. The fish were collected in the lake region, municipality of Tartarugalzinho, in the state of Amapá, Brazil. The new species was found parasitizing the urinary bladder of M. festivus. Spores were 11.5 ±1.1 (10.4-12.6) µm long and 10.9 ±1 (9.9-11.9) µm wide, and polar capsules were equally sized, measuring 4.9 ±0.5 (4.4-5.4) µm long and 3.4 ±0.9 (2.5-4.3) µm wide, with a pyriform shape, convergent with the apical region of the spore. The polar filament was wound with 5 to 6 turns. Morphological, morphometric, molecular and phylogenetic analysis proved that it is a new species of Hoferellus in the Amazon region.

This study was carried out in northern Brazil to determine the prevalence of helminth parasites that infect Phalacrocorax brasilianus (Gmelin, 1789). Between July 2020 and July 2023, adult and larvae parasites were collected from the respiratory and gastrointestinal tract of 30 birds that died in fishing nets and in fishing corral in the municipality of Soure on Marajó Island. The identified parasites included the nematodes Contracaecum sp., Contracaecum australe, Contracaecum rudolphii sensu lato, Contracaecum microcephalum, Contracaecum multipapillatum, Syncuaria squamata, Desportesius invaginatus, Tetrameres sp., Aplectana sp., Cyathostoma sp., Eucoleus contortus, Baruscapillaria spiculata, Baruscapillaria appendiculata; the trematodes Drepanocephalus spathans, Austrodiplostomum mordax, Austrodiplostomum compactum, Hysteromorpha triloba; the cestodes Paradilepis caballeroi; and the acanthocephalans Andracantha sp., Southwellina hispida and Southwellina macracanthus. The whole prevalence was 96.66% (29/30) and the most frequent helminths were nematodes (96.66%; 29/30), followed by acanthocephalans (66.66%; 20/30). These data increase the knowledge about helminths in cormorants widely distributed to Marajó Island.

Background: The diaphragm, the main muscle involved in respiration and one of those responsible for maintaining life, is still little explored in terms of its morphology in wild animals. There are few studies on the anatomy of Eira barbara, a carnivorous mustelid that is a victim of the urbanization process. In order to contribute to the conservation of the species, we described the topography and morphology of the diaphragm, which may be involved in injuries caused by the impacts of human activities., Results: We studied five specimens of Eira barbara, whose diaphragmatic muscle had a dorsal insertion on the 14th thoracic vertebra, laterally between the 8th and 13th intercostal space (EIC) and ventrally on the 8th EIC, with attachment to the xiphoid process. Consisting of three muscle regions (lumbar, costal and sternal), the diaphragm in Eira barbara showed radially arranged bundles, with the right costal muscle being slimmer than the left; the left pillar wider than the right and between them were the aortic and esophageal hiatuses. The Y-shaped tendinous center housed the foramen of the vena cava bordering the right costal region. In the most dorsal portion of the diaphragm, between the costal regions and the diaphragmatic pillar, we found two triangular-shaped regions devoid of muscle., Conclusions: Our findings, when compared with the current literature, indicate that the location and positioning of the diaphragm are independent of the physical conformation of the species, and that the right costal region, as well as the triangular areas devoid of musculature, may be fragile points for herniation in cases of Eira barbara being run over., (© 2024. The Author(s).)

The species Cuniculus paca is highly subject to predation, whether natural or anthropogenic, and the ability of species to withstand different levels of depredation depends directly on their reproductive dynamics. However, there is little literature on the developmental biology of this species, and so the aim of this paper was to describe the fetal development of the urinary tract of C. paca through morphological analysis. Twelve specimens with estimated gestational ages of between 75 and 157 days were used, divided into 3 groups. We found the urinary tract in pelvic-abdominal topography with macroscopic differentiation between the organs already present in the first ages studied; in addition, the microscopic structural pattern changed little between the groups. This evidence reinforces the precocial development of these individuals. RESEARCH HIGHLIGHTS: With the results obtained for development of urinary tract in Cuniculus paca reinforces the precocial development of these individuals. The urinary tract had pelvic-abdominal topography with macroscopic differentiation between the organs already present in the first ages studied. The microscopic structural pattern changed little between the groups. At all analyzed fetal ages, the cortical region of kidney was characterized by the presence of glomeruli arranged throughout the region, formed by capillary plexuses surrounded by a glomerular capsule. In addition, the cortical region also presented convoluted tubules with cubic epithelial tissue cells and a brush border. The presence of a developed macula densa was observed next to the glomeruli, suggesting the initial formation of the fetal juxtaglomerular apparatus., (© 2024 Wiley Periodicals LLC.)

Cucullanus lithodorasi n. sp. (Nematoda: Cucullanidae), collected from the intestine of Lithodoras dorsalis (Siluriformes) and waters of the north coast of Brazil is described based on light and scanning electron microscopic observations. The new species differs from its congeners in the number and arrangement of cloacal papillae: five precloacal pairs and five postcloacal pairs and presence of unpaired ventral papillae located slightly anterior to the cloaca. This is the third nominal species of the genus infecting fishes from brackish water from Brazil.

Choloepus didactylus has reduced metabolism and difficulty in thermoregulation owing to its low body mass, and there are few studies related to the vascularization of abdominal and thoracic organs in this species. Therefore, we macroscopically described the arteries that comprise the aortic arch, thoracic aorta, and abdominal aorta. Six specimens were used, and their arterial systems filled with red latex before fixation in 10% formaldehyde, and fragments of the rete mirabile were processed for histological analysis using light and scanning electron microscopy. In these species, the aortic arch had two branches: the brachiocephalic trunk and left subclavian artery. The initial portion of the abdominal aorta presented four different ramifications, besides to the peculiarities of the adrenal, renal, and iliac arteries. Microscopy of the rete mirabile revealed a muscular artery surrounded by smaller muscular arteries, veins, nerves, and lymphatic tissue joined by connective tissue. Thus, the data obtained have clinical and surgical importance, with applicability in procedures involving vascularization of the thoracic and abdominal organs. We suggest that the rete mirabile is an efficient thermoregulatory structure because it allows the accumulation of blood and the countercurrent heat exchange, as there is no blood mixing., (© 2023 American Association for Anatomy.)

New morphological, morphometric and scanning electron microscopy data of a nematode of the family Anisakidae, recovered from a specimen of Kogia sima, a cetacean that died off the northern coast of Brazil, are presented in this paper. Morphological features such as the violin-shaped ventricle and short and equal spicules, as well as the distribution of post-cloacal papillae and specificity for the definitive host (Kogiidae cetaceans) demonstrate similarity to Skrjabinisakis paggiae. This research records Kogia sima and S. paggiae on the estuarine coast of Pará, northern Brazil.

Thirteen black agouti (Dasyprocta fuliginosa) male fetuses, acquired in two areas of the Amazon Forest, were used for the purpose of morphologically describing the fetal male urogenital organs with a focus on addressing histological and macroscopic aspects. The organs of interest were dissected and photographed in situ and ex situ. Fragments were collected and subjected to routine histological processing for inclusion in paraffin, which was cut and stained by haematoxylin and eosin and Gomori's Trichrome methods and subsequently analysed in a light microscope. The results showed that the urinary tract is like that of domestic animals and is composed of smooth unilobed kidneys covered by a dense capsule of connective tissue and divided into two well-defined regions, cortical and medullary. Ureters, urethra and urinary bladder also showed macroscopic and microscopic characteristics similar to those of domestic animals. The penis of these animals has fibroelastic characteristics, with numerous keratinized structures at its apex. In the middle third of the penis, a "U" shaped penile flexure was seen; the glans penis is covered by a keratinized epidermis containing horny spicules. The presence of a penile bone in an endochondral ossification process was observed, being more developed in gestational ages greater than 76 days. The annex glands were not observed, probably because they were fetuses; only the ampulla of the ductus deferens was identified., (© 2023 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.)

This study aimed to redescribe two species of Ozolaimus, parasites of free-living green iguanas native to Marajó Island. The gastrointestinal system of four iguana specimens was evaluated for the presence of helminths. Altogether, 12,028 nematodes were found, with a prevalence of 100%, an infection range of 780 to 7,736 nematodes, an infection intensity of 3.007, and a mean abundance of 3,007. Light microscopy and scanning electron microscopy were used to determine the species of nematodes found. The cecum was the site of infection that had the highest parasitic load. Morphologically, the nematodes were compatible with the genus Ozolaimus Dujardin, 1844, with the species Ozolaimus megatyphlon (Rudolphi, 1819) Dujardin, 1845, and Ozolaimus cirratus Linstow, 1906. Scanning electron microscopy showed the presence of small structures (serrated in Ozolaimus cirratus and rounded in Ozolaimus megatyphlon) located below the esophageal leaves. We also evidenced the phasmids in both species; this is the first record of these structures in nematodes of the genus Ozolaimus. In addition, this work expands the records on the geographic distribution of these parasites.

Capillaria Zeder, 1800, parasitizes the organs and tissues of several hosts, including the domestic duck Cairina moschata (Linnaeus). This article describes a new species of Capillaria in domestic ducks identified based on morphological studies and molecular analyses of the ribosomal RNA gene. Thirty-eight specimens of C. moschata from the municipality of Soure, Marajó Island, Pará, Brazil. The organs of the birds' digestive tract were analyzed under a stereomicroscope to confirm the parasitic infection, after which the collected nematodes were identified by light microscopy, scanning electron microscopy, and molecular analysis. Capillariids parasitized the intestine and cecum of the examined birds. These parasites had three bacillary bands and a pair of elongated precloacal papillae on the tail. Phylogenetic analysis indicated that the new species formed a sister clade with Capillaria spinulosa (Linstow, 1890), as described in Indonesia and Japan. Based on morphological distinctions and molecular data, Capillaria cairina n. sp. can be considered a new parasite species of C. moschata in the Brazilian Amazon.

Caiman crocodilus is among the most abundant and widely distributed predators in the Neotropical region. These animals consume prey such as crustaceans, birds, small mammals, reptiles, amphibians, and fish, which can carry infective larval forms of nematodes. Brevimulticaecum has few studies on its morphology available, lacking detailed images. Therefore, the aim of this study was to redescribe Brevimulticaecum baylisi, stomach parasite of Caiman crocodilus, from subsistence hunting in the Yavari-Mirin River, Peruvian Amazon, using light and scanning electron microscopy. Four caimans were analyzed, and, macroscopically, all had ulcerative lesions in the stomach caused by this parasite. Histopathology showed an inflammatory infiltrate with a predominance of lymphocytes. Morphological characteristics of nematodes include the presence of three diamond-shaped lips wider than they are long, interlabia pyramidal, excretory pore located above the nerve ring, present intestinal cecum, ventriculus with five ventricular appendages, and long, winged spicules. These morphological characters, added to the number and distribution of the pre- and postcloacal papillae of the male specimens, allowed the identification of these parasites as B. baylisi. Scanning electron microscopy of these nematodes showed the presence of a dentigerous ridge on the inner surface of the lips in both sexes, while in males, the presence of a horseshoe-shaped median papilla was observed on the upper lip of the cloaca. Our research, therefore, adds these characteristics to the original description of B. baylisi, in addition to expanding the biogeographical distribution of this parasite., Competing Interests: Declaration of Competing Interest The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The genus Baruscapillaria Moravec, 1982 has six valid species recorded in birds Phalacrocoracidae, namely Baruscapillaria appendiculata Freitas, 1933, B. spiculata Freitas, 1933, B. carbonis (Dubinin & Dubinina, 1940), B. jaenschi (Johnston & Mawson, 1945), B. phalacrocoraxi (Borgarenko, 1975) and B. rudolphii Moravec, Scholz and Našincová, 1994. Helminthological tests carried out on cormorants of the species Phalacrocorax brasilianus (Gmelin), a migratory bird that occurs in the northeast of the State of Pará, Brazil, demonstrate B. appendiculata parasitizing the cloaca of these birds, through light microscopy, scanning electron microscopy and molecular biology. These studies allowed a redescription of males and females of this nematode in these hosts and in this geographical area through integrative taxonomy. The occurrence of lesions in the cloaca caused by this nematode parasite was registered using histological analysis. This is a new geographic report for this nematode.

For the first time in Brazil, Contracaecum australe is recorded parasitizing Phalacrocorax brasilianus (Aves, Suliformes, Phalacrocoracidae) from the Marine Extractive Reserve of Soure on Marajó Island, Brazilian Amazon. Its morphology revealed a body with a transversally striated cuticle, smooth or slightly cleft interlabia, lips with auricles, labial papillae, and conspicuous amphids. In males, the presence of the median papilla on the upper lip of the cloaca and spicules that reach almost half of the body of the parasite. These morphological characters, added to the number and distribution of the pre- and postcloacal papillae of the male specimens, and supported by the molecular phylogeny from the analysis of the ITS-1, 5.8S and ITS-2 genes, allowed the identification of these parasites.

A new species of Spirocamallanus Olsen, 1952 (Camallanidae), is described based on specimens found parasitizing Propimelodus eigenmanni (Siluriformes), an Amazonian fish. The new species has buccal capsule with 15-19 spiral ridges, males with caudal alae supported by 3 pairs of precloacal and 6 pairs of postcloacal papillae, and two terminal spikes on tail end, and females with a digitiform projection ending in two small spikes on tail end. The new species shares characteristics with a group of Neotropical Spirocamallanus that are characterized by the presence of caudal alae, 3 pairs of precloacal papillae, unequal spicules and the presence of spines on the tail tip of males. Several species of this group have been reported from marine environments, in contrast with Spirocamallanus delirae n. sp., which occurs in Amazon freshwaters. Among the Brazilian congeners placed in the referred morphological group are S. rarus, S. freitasi, S. macaensis, and S. halithophus, the last two being parasites of marine fishes. The new species differs from S. rarus (3-4), S. macaensis (12-15), and S. halithophus (10-15) based on the number of spirals in the buccal capsule and from S. fretasi based on the morphology of the larger spicule that is bifid in the former and undivided in the new species. The present description of Spirocamallanus delirae n. sp. adds new data to the biodiversity of parasites from freshwater siluriform catfish in the Neotropical region., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

About 20 valid species of the genus Rhabdias are known in the Neotropical region. The present study aimed to describe two new species of Rhabdias parasitizing the lungs of Leptodactylus macrosternum and Leptodactylus podicipinus from Brazil. Distinctive characteristics between these species are numerous and based on body size, size of the buccal capsule, shape and size of the oesophagus, and position of the vulva. Molecular data based on ribosomal genes 28S and ITS region and mitochondrial COI of the two species are presented. Molecular analysis and comparison of the partial mitochondrial COI sequence of Rhabdias matogrossensis n. sp. and Rhabdias guaianensis n. sp. revealed a genetic divergence between these new species and the sequences of Rhabdias spp. previously deposited in GenBank. In the phylogenetic analysis, R. matogrossensis n. sp. was grouped with R. breviensis species complex, and R. guaianensis n. sp. was grouped as a sister group of R. cf. stenochepala. This study contributes to improving the diversity of known species of Rhabdias described in Brazilian anurans., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Rhabdias fuelleborni was described by Travassos (1926), who identified it in the lungs of Rhinella gr. marina (=Bufo marinus) from São Paulo. Later, Kloss (1971) added new information on the morphology and diagnosis of the species and new data on host and localities. However, its taxonomic status remains uncertain, due in particular to the morphological uniformity of Rhabdias spp., while the original description lacks important morphological data. In the present study, we found and reevaluated the type series of R. fuelleborni, as well as examining fresh material obtained from the type host and type locality, using light and scanning electron microscopy and molecular tools. The type series was deposited by Travassos (1926), and according to museum records the type locality is Paraty, Rio de Janeiro, Brazil. Our morphological and molecular analyses reinforce the taxonomic validity of this species, while molecular phylogeny identified a close relationship between R. fuelleborni and Rhabdias sp.4 and Rhabdias sp. from other studies, and from bufonids. Also R. fuelleborni are sister taxa with R. cf. stenocephala from Leptodactylidae from the northeast of Brazil and R. vencesi from Boophis madagascarariensis, Madagascar, according to mitochondrial COI gene., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The puffer fish Colomesus psittacus, is not commercialized on Marajó Island. They are captured as bycacth and discarded dead in the environment in artisanal fisheries that occur in the estuaries of northern Brazil. In this sense, the objective was to identify the parasites present in the gills and to evaluate the histopathological alterations caused by these nematodes of the genus Huffmanela. Fifty-five fish were analyzed, and thirty-five specimens showed the parasite in the gills. Morphological characteristics suggest that it is a new species of the genus Huffmanela, and the histopathological exams showed an edematous inflammation in the secondary lamella and the presence of eggs of this nematode, which is the first record of this parasite in C. psittacus in Brazil.

Paw pads are specializations of the integument and important shock absorbers of the locomotor system, as well as pressure, pain, temperature, storage and excretion sensors. Aiming to describe the paw pad morphology of the main arboreal xenarthras species in the Amazon, 16 animals were studied, Bradypus variegatus (6), Choloepus didactylus (5), Tamandua tetradactyla (3) and Cyclopes didactylus (2) that after death were donated to the Animal Morphological Research Laboratory (LaPMA / Ufra). The corpses were thawed and fixed with 10% aqueous formalin solution. The paw pads were measured, photographed and removed by skin incision dorsally to them. Fragments were used for routine histological processing, using two staining techniques: Hematoxylin-Eosin (HE) and Gomori's Trichrome, in sections of 6 to 8 µm. Choloepus didactylus, Tamandua tetradactyla and Cyclopes didactylus have digital paw pads, one in each digit, and one palm, as well as a plantar, whose shapes and colours are distinct from each other. Bradypus variegatus, however, has only one palmar and one plantar pad. Histologically, they have keratinized stratified squamous epithelium, supported by a large amount of collagen fibres and fibroblast cords in the dermis and hypodermis. Groups of eccrine sweat glands were observed in the reticular dermis of C. didactylus, B. variegatus, T. tetradactyla and only in the hypodermis of Cyclopes didactylus., (© 2022 Wiley-VCH GmbH.)

Developmental ultrastructure of late embryos and cotylocidium larval morphogenesis of Rohdella amazonica, an aspidogastrean parasite of fish, were studied to reveal the functional aspects of larvigenesis within the egg as well as phylogenetically relevant characteristics of the embryos and larvae in this basal trematode group. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard methods of transmission electron microscopy (TEM) and cytochemistry. During late cleavage and rearrangement of the blastomeres, the vitelline syncytium that plays a role in eggshell formation and nutrient provision to the embryo completes its apoptotic degeneration as the embryonic mass grows substantially. Early larval morphogenesis involves cellular positioning that defines the anteroposterior polarity of the differentiating larva. Progressing through larvigenesis, the anterior end forms a muscular oral sucker surrounding the mouth, which leads inward into the pharynx and expanding digestive cavity. At the posterior end, a large disc forms as a precursor to the eventual ventral disc. The fully formed cotylocidium, still within the eggshell, is flexed ventrally, bringing the 2 poles into near juxtaposition. The neodermatan tegument with outwardly projecting small microvilli becomes fully formed, as myocytons, a protonephridial system, and 2 glandular regions occupy the body's interior. The ultrastructural features described here are very similar to those reported for Aspidogaster limacoides from fish and somewhat similar to those reported for Cotylogaster occidentalis from molluscs, but differ from the more diverse larvae of neodermatan taxa that have been studied more extensively., (© American Society of Parasitologists 2022.)

Egg structure and early embryonic development of the aspidogastrean, Rohdella amazonica, a basal trematode, were studied by transmission electron microscopy (TEM) to gain insight into functional, developmental, and phylogenetic characteristics. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard TEM methods. By the time of pronuclear fusion, the fertilized zygote was already enclosed in a thick, electron-dense pre-operculate eggshell and an underlying layer of vitellocytes that fused into a vitelline syncytium as they were still secreting their shell granules. When cleavage commenced, a small number of macromeres moved to the area just underneath the eggshell, where they fused to form a single syncytial embryonic envelope. Simultaneously, the smaller blastomeres continued to divide as they maintained contact with each other, but remained separate from the vitelline syncytium. Concurrent with these cellular changes, a thickened knob expanded at one pole of the eggshell and began to form an opercular suture. By the time the operculum was fully formed, the vitelline syncytium had mostly degenerated, while the smaller blastomeres had become cohesive as a single mass that preceded the differentiation and morphogenesis of the cotylocidium larva. The general pattern of cleavage and eggshell formation resembles that of other trematodes and polylecithal cestodes, but the single embryonic envelope has been reported only in a few basal taxa. The only other aspidogastrean studied in detail to date is very similar, indicating close phylogenetic affinity and conservatism within this basal neodermatan and neoophoran group., (© American Society of Parasitologists 2022.)

Eira barbara, popularly known as irara, is a medium-sized carnivore member of the Mustelidae family. Despite its important role in the ecosystems in which its lives, data on the internal morphology of E. barbara remains scarce. Therefore, this study aimed to provide knowledge regarding the anatomy of the male reproductive system of this species to improve understanding of its reproduction to inform its conservation. We studied seven specimens who had died after being run over. The specimens were dissected for the evaluation of the reproductive system, which comprised a globular scrotum; a small pendulum covered with light-coloured hair; a pair of testicles of firm consistency and ellipsoid shape and suspended in the scrotum by the spermatic cord; a paired duct system; an ampoule of the deferens duct and prostate constituting the set of attached glands; a urethra divided into pelvic and penile portions; a penis with a baculum having a novel "C" shaped apex; and a prepuce. Microscopically, the testicular parenchyma consisted of seminiferous tubules separated by intertubular spaces formed by loose connective tissue, fibrocytes, Leydig cells, and blood and lymph vessels. The epididymis was surrounded by a capsule of dense connective tissue and extended to form septa. The baculum was microscopically classified as a compact bone containing several bony lamellae with osteocytes and osteoblasts. The macro and microscopic findings were generally similar to those of domestic carnivores, with some notable differences., (© 2022 Wiley-VCH GmbH.)

Bradypus variegatus, popularly known as common sloth or brown-throated sloth, is a species with wide geographical distribution in Brazil. Expand on the literature about the species, we aimed to describe the morphology of its eye and its main annexes. For this study, six frozen specimens donated to the Animal Morphological Research Laboratory of the Federal Rural University of Amazonia were used. The specimens were fixed in a 10% aqueous solution of formaldehyde. The structures that constitute the ocular apparatus were identified and described after dissection and histological analysis using light microscopy. The bulbar conjunctiva presented a stratified cuboidal epithelium, with a considerable number of serous glands. The stroma layer and the posterior limiting lamina were found well defined in the species. The corneoscleral meshwork possessed a large opening for drainage of aqueous humour, followed by a wide retinal region, in which a layer of photoreceptors was visualized. Cones and rods could not be discriminated from each other. Microscopy of the medial angle of the eye revealed the cartilage and glands of the third eyelid, and a well-developed lacrimal gland structure. Bradypus variegatus distinguishing features and similarities in comparison with other domestic and wild mammal and bird species already described were investigated, which expounded the limited knowledge that is presently available on the morphology of wild fauna. The data extend the limited knowledge that are presently available on the ocular histology of B. variegatus., (© 2021 Wiley-VCH GmbH.)

Raising of Muscovy ducks Cairina moschata domestica for subsistence of human populations is common in northern Brazil, although their helminth infections have been poorly investigated, despite the possible presence of helminths with zoonotic potential. The aim of this study was to investigate the diversity of parasite endohelminths in C. moschata domestica raised in the Marajó Island region, state of Pará, Brazilian Amazon region. Of 33 specimens examined, 90.9% were parasitized by one or more parasite species, for a total of 926 parasites recorded. The species mean richness of endohelminths varied from 0 to 6, and there was a predominance of hosts with 1 to 2 species of parasite endohelminths and low prevalence and low abundance of parasites. This was the first report of larvae of Anisakis sp., Contracaecum sp., Hysterotylacium sp., Raphidascaris sp., Eustrongylides sp., Syngamus sp., Ascocotyle sp. and Athesmia heterolecithodes for C. moschata domestica . The parasitic community of C. moschata domestica was composed of 11 species, with a high species richness for nematode species and a small number of digeneans., Competing Interests: Conflict of interestAuthors declare that there is no conflict of interest regarding the publication of this paper., (© Indian Society for Parasitology 2021.)

Helminthiasis occurs frequently in wild or domestic pigs in the most varied environments or production systems; however, the literature includes few taxonomic studies for the purpose of expanding this knowledge about the parasitic diversity in these animals. Thus, in order to expand this knowledge regarding parasitic diversity in these animals, the present study reports the occurrence and redescribes Globocephalus urosubulatus infecting domestic pigs in the state of Pará, Brazil, using microscopy. Four hundred and ten specimens of Sus scrofa intestinal nematodes were collected extensively in the municipality of Moju, northeastern mesoregion of Pará and observed under light and scanning electron microscopy. Based on morphological characteristics, the nematodes were identified as G. urosubulatus, and new morphological data were added by light microscopy and scanning electron microscopy for the diagnosis of this parasite.

Coelozoic parasites of the family Myxidiidae were observed in fish of the order Characiformes captured in the middle Tocantins River, Maranhão, Brazil, within the transition between the Cerrado savanna biome and the eastern extreme of the Brazilian Amazon Forest. The analysis of the morphological characteristics of the parasites, complemented with a Bayesian phylogenetic analysis, supported the description of new specie Myxidium imperatrizensis n. sp., found parasitising the gallbladder of specimens of the fish Triportheus angulatus. The study is also only the second report of the occurrence of Myxidium parasites in fish of the family Triportheidae in Brazilian rivers. The results of the present study expand the known distribution of the genera Myxidium the basin of the Tocantins River, the largest hydrographic basin located entirely within Brazil, which encompasses parts of both the Cerrado and Amazon biomes., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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.

Fermentative herbivorous animals have peculiar conformations of the digestive system. It is known that B. variegatus obtained the capacity for evolutionary adaptation, due to their ecology and eating habits. However, despite the literature on feeding management for this species, there is a lack of published information regarding its gastric morphology, and such information would support a better understanding on the diet and digestion of these individuals. We found seven gastric compartments, which histologically revealed three distinct patterns: an aglandular keratinized fraction (mechanical stomach) and two glandular fractions, one a mucus secretor and the other one composed of acid secreting cells (chemical stomach). With these evidences we understand that these individuals have gastric resemblance to ruminants, with some inherent peculiarities of this species, including the transit of the bolus., (© 2020 Wiley Periodicals LLC.)

This study aimed to investigate the presence of nematodes Spirocamallanus krameri and Contracaecum sp. in Hoplerythrinus unitaeniatus caught in a lake in the state of Pará, in northern Brazil, eastern Amazon region (Brazil). From 92 hosts, 83.7% were infected, and a total of 401 parasites were covered. There was a high prevalence of S. krameri, while the predominance was of Contracaecum sp. larvae. Both parasite species presented aggregated dispersion, and abundance of these parasites presented positive correlation with weight and length of the hosts. Morphological and morphometric data of third-stage larvae of Contracaecum sp. are described.

The genus Cotylophoron belongs to the Paramphistomidae family and its definitive hosts are ruminants in general. This work describes the presence of a new species of the gender, a parasite in the rumen and reticulum of Bubalus bubalis, on Marajó Island in the Eastern Brazilian Amazon, using of light microscopy, scanning electronic microscopy and molecular biology techniques. One hundred and ten animals were analyzed, of which 4.54% were parasitized by flukes in their adult forms. The helminths were found fixed to the ruminal mucosa and present Liorchis-type pharynx, Cotylophoron-type genital sucker, oblique testicles larger than the ovary, uterus in rings full of eggs and Cotylophoron-type acetabulum. These morphologic characters do not fit into any previously described species. Thus, it is proposed that this is a new species in the genus Cotylophoron. The present work expands the record of parasitism by helminths in Bubalus bubalis, this being the first record of trematoda from the genus Cotylophoron for this host in the Brazilian Amazon.

Rhabdias pocoto n. sp. is herein described from the lungs of the swamp frog Pseudopaludicola pocoto Magalhães, Loebmann, Nogueira, Kokubum, Baptista, Haddad & Garda, 2014, from the Caatinga biome in the state of Ceará, in north-eastern Brazil. The new species is characterized by a body that dilates posteriorly, six small lips (protuberances) and two rounded lateral expansions of cuticular inflation on the anterior end, each containing an amorphous gland-like structure inside and a short and conical tail. Additionally, molecular analysis and comparison of the partial mitochondrial cytochrome c oxidase I sequence of R. pocoto n. sp. revealed genetic divergence between the new species and the sequences of Rhabdias spp. previously deposited in GenBank. Phylogenetic analysis grouped the new taxon into the R. pseudosphaerocephala species complex + R. glaurungi clade. The new discovery represents the 19th species of Rhabdias spp. described in the Neotropical region, the ninth in Brazil and the first species of Rhabdias found parasitizing South American frogs of the genus Pseudopaludicola, as well as the first Caatinga biome species of Rhabdias.

This study aimed to describe the occurrence, morphology and prevalence of Spirocamallanus krameri, a parasite of Hoplerythrinus unitaeniatus collected in state of Pará, Brazil. The morphological and morphometric characteristics are consistent with the species S. krameri, by having a hexagonal mouth opening, 16 cephalic papillae and two lateral papillae on the amphids. The buccal capsule is internally different in both sexes, with (11-13) spiral ridges in males and (13-17) spiral ridges in females. The basal ring is well developed, and three teeth are present in males and absent in females. Ten sessile caudal papillae and a pair of phasmidial pores occur in males. The spicules are small, subequal, 81-101 µm in length and the tail is tapered. The vulva in females is postequatorial, the tail is conical with lateral phasmidial pores. Among the species of Spirocamallanus that have short spicules, the general morphology of S. krameri most resembles that of S. inopinatus, but differs from that species, which have two cephalic teeth visible (absent in S. krameri) and specimens of S. inopinatus do not have sexual dimorphism in the buccal capsule of present in S. krameri.

Mammomonogamus spp. are parasites with curious characteristics, such as the "Y" shape that results from male and female maintaining the permanent copulation position and the controversial presence or absence of spicules. These nematodes are hematophagous and cause damage to the upper respiratory tracts of cattle, sheep, goats, deer, wild yaks, and orangutans. Human infection is rare and most cases until now have been in the Caribbean Islands or in Brazil, and mainly in farmworkers but recently there have been reports affecting tourists. In the present work, the parasites were recovered from the laryngopharynx and larynx region of Bubalus bubalis on the island of Marajó, Pará, Brazil. Different microscopy methodologies were applied (bright field, fluorescence, and scanning electron microscopy) to explore the ultrastructural details of the anterior end, genital structures and the host tissue damage caused by the nematodes. The well-developed mouth is an important structure in the identification of these nematodes and used by the parasite to adhere to the host's tissue. Different methodologies in microscopy and molecular biology contributed to a detailed morphological description and showed the phenotypic position of Mammomonogamus laryngeus. Light and scanning electron microscopy (SEM) showed details of the papillae, amphids, festoons, ribs, and teeth. Fluorescence microscopy enabled a detailed characterization of different structures, such as the bursal rays and SEM enabled the visualization of the specialized features of the cuticle surface in the male and female. Histopathological analyses, cryofracture and environmental SEM experiments of the infected tissues were carried out in order to investigate the lesions resultant from the parasitism. In addition, the parasite couples were submitted to cryofracture and these results revealed details of the reproductive structures of both sexes, including the male spicule., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Buteogallus schistaceus (Sundevall) is an endemic bird of prey from the Amazon region, with a declining population according to international conservation agencies. The objective of this study was to report the occurrence of a parasitic nematodes in an individual treated at the Ambulatório de Animais Silvestres of Universidade Federal Rural da Amazônia, Belém campus. The animal was captured on campus and showed no resistance to capture. Fluid therapy and deworming were made, later the bird regurgited ten nematodes identified as belonging to the genus Procyrnea Chabaud (1958). Reviewing the scientific literature, it was found that so far there are no records on the helminth fauna of this bird species, which is therefore the first report of a nematode in B. schistaceus.

Fossil evidence suggests that scent glands are basal features of Testudines. However, we know little about the structure of these glands in the Brazilian Kinosternidae. In this study, we described the macroscopic anatomy, histology, and histochemistry of the scent glands of three males and three females of Kinosternon scorpioides scorpioides from the Marajó mesoregion, Pará State, Brazil. In all of the specimens analyzed, regardless of sex, we found four scent glands, including two axillary and two inguinal glands that were structurally similar to each other. Each gland consisted of a single holocrine secretory lobule, a large lumen surrounded by relatively thin glandular secretory epithelium, an adjacent narrow layer of loose connective tissue, and a thick layer of skeletal striated muscle tissue surrounded by a serous tunic. The secretory epithelium produced a characteristic malodorous yellowish substance that was passed via a single duct through a bone channel in the bridge connecting the carapace to the plastron and excreted through an outer pore in the plate of each respective gland. Histologically, the secretory epithelium presented cells with two types of secretory vacuoles. Type 1 vacuoles stained red were the largest and most frequently found, and stained positively with Periodic acid-Schiff (PAS), suggesting they contained glycoproteic complexes. Type 2 vacuoles were translucent, smaller in size and fewer in number, and negative for PAS staining. Because they are very primitive structures, scent glands must play important roles in the lives of chelonians, but their real function remains unknown. Several hypotheses suggest that they can act as protection against ectoparasites, as a repellent of predators, in addition to attracting mates and eliciting other pheromonal responses. In this study, all animals reacted by exuding malodorous substances when handled, as a form of defense. However, these are just assumptions that need to be clarified with additional studies on animal behavior. Anat Rec, 303:1489-1500, 2020. © 2019 American Association for Anatomy., (© 2019 American Association for Anatomy.)

The tayra (Eira barbara) is a mammal belonging to the Mustelidae family that occurs in all Brazilian biomes. The present work aimed to describe the morphology of the tongue of these specimens highlighting their structures and particularities that will serve as a subsidy to elucidate the anatomy of the same and for comparative studies among other species of domestic and wild animals. Five adult male specimens of E. barbara were studied, which were fixed using 10% aqueous formaldehyde solution. The tongue was removed by opening the oral cavity and separating the maxillary/mandible bone complex. Being in possession of the material, photodocumentations and collection of the fragments were made for the proper preparation of histological slides and Scanning Electron Microscopy (SEM). The lingual papillae found in tayra were mechanical: filiform and conical; and gustative: fungiform and circumvallated. Histologically, the papillae are constituted by keratinized stratified epithelium and in the innermost region, it was composed of tissue connective dense unshaped followed by a layer of muscle bundles of skeletal striated. In the region of the root of the tongue of E. barbara, there were a set of small mixed salivary glands (serous and mucous) and the punctual presence of gustatory corpuscles at the level of epithelium. The morphological description of the E. barbara tongue revealed similarity to that described in literature for other domestic and wild mammals. However, the particularity of the absence of foliate papilla and the quantitative of four papillae circumvallate in the region of the root of the tongue of this species., (© 2020 Blackwell Verlag GmbH.)

The present work provides the first ultrastructural analysis of spermatozoa of two digeneans (Aphanurus stossichii (Monticelli, 1891) and Ectenurus lepidus Looss, 1907) belonging to the unexplored subfamilies of the Hemiuridae, namely, the Aphanurinae and the Dinurinae. In March 2019, these hemiurids were collected respectively from the digestive tract of the bogue Boops boops (Teleostei, Sparidae) and the Atlantic horse mackerel Trachurus trachurus (Teleostei, Carangidae) captured in the coastal zone of the Mediterranean Sea, off La Chebba (Tunisia). The ultrastructural study reveals that both spermatozoa exhibit the Bakhoum et al.'s type II of the digenean sperm cells characterized by the presence of two 9+'1' axonemes, an external ornamentation of the plasma membrane not associated with cortical microtubules and located in the anterior part of the spermatozoon, a single bundle of cortical microtubules, the maximum number of cortical microtubules located in a middle part of the sperm cell, and one mitochondrion. Moreover, they share several ultrastructural features with the studied spermatozoa of Hemiuridae such as the presence of two axonemes with the 9+'1' trepaxonematan pattern, a reduced number of parallel cortical microtubules organized into one field with their maximum number located in the median (A. stossichii) or posterior (E. lepidus) part of the spermatozoon, an external ornamentation of the plasma membrane in the anterior part of the spermatozoon, one mitochondrion, a nucleus, and a small amount of glycogen granules. However, the two studied hemiurids could be distinguished by the morphology of the anterior and posterior spermatozoon extremities and the presence of mitochondrial matrix granules in A. stossichii.

Among the avian used for human consumption, the Muscovy duck is well adapted to various climatic conditions and its breeding is widespread due to its easy handling, and its meat is widely consumed and appreciated, especially in the cuisine of northern Brazil. The present study aimed to report and identify taxonomically the nematodes found in the esophagus of Muscovy ducks reared and marketed in the municipality of Soure, Marajó Island, state of Pará, Brazil, and discuss its zoonotic potential to human. The samples consisted of 30 specimens of Cairina moschata domestica analyzed. A total of 258 nematodes were recovered, which were strongly fixed in the esophageal mucosa of hosts. The morphological and morphometric characteristics were compatible with Anisakis third-stage larvae.

The ultrastructural characteristics of the mature spermatozoon of the aspidogastrean Rohdella amazonica (Aspidogastridae, Rohdellinae) were studied by means of transmission electron microscopy. The sperm cell shows two axonemes of the 9 + '1' trepaxonematan pattern of Platyhelminthes, parallel cortical microtubules, a well-developed lateral expansion, external ornamentation of the plasma membrane, one mitochondrion, an electron-dense ring, a nucleus and granules of glycogen. The present results were compared with those observed in the aspidogastreans studied to date and in other Platyhelminthes. The lateral expansion and the electron-dense ring are typical characters for aspidogastreans. Although a lateral expansion has been described in other Platyhelminthes such as monogeneans and digeneans, the Aspidogastrea shows a much larger lateral expansion with both peripheral and internal microtubules. The dense ring is observed as a cylinder in a longitudinal view and shows a more granular appearance in sperm cells from the seminal vesicle in comparison to a more electron-dense appearance in sperm cells from the seminal uterine receptacle.

Among the Nematodes of Cerdocyon thous, the genus Pterygodermatites is characteristic for presenting cuticular projections along the body, being mentioned in different hosts in South America, although there are no records of its occurrence in the Amazon Biome. To enable further exploration in terms of their morphology and morphometry, the nematodes collected from cadavers of C. thous were fixed and observed using bright field microscopy and scanning electron microscopy, revealing characteristics compatible with P. (Multipectines) affinis, thus contributing more information about the geographic distribution of the parasite, as well as knowledge of the helminthological fauna of wild mammals in the Brazilian Amazon.

The family Capillariidae is one of the most important in the superfamily Trichinelloidea, with 27 genera and more than 300 species parasitizing vertebrates. This study considers the morphology, morphometry and prevalence of Eucoleus contortus parasitizing the Muscovy duck Cairina moschata domestica esophagus from Marajó Island, in State of Pará, Brazil. Morphologically the nematodes had a filiform body, with transversely striated cuticle, long esophagus, divided into two parts, one muscular and another consisting of stichocytes, spicule weakly sclerotized, spiny sheath and pseudobursa present in males. Females had a pre-equatorial vulva, barrel-shaped eggs and were bioperculated. In the northern region of Brazil, the Muscovy duck is an abundant bird, and one of the items in the food supply for human communities. The occurrence of E. contortus adds data to the biodiversity of parasites described in Anseriform birds of the Brazilian Amazon, especially those used as source of protein by human communities of Marajó.

The ocelot (Leopardus pardalis) is a Felidae of wide geographical distribution and food flexibility; therefore, it is essential to understand the morphology of the species. Thus, we aimed to describe its lingual morphology in order to gain information regarding the anatomy of this carnivore's digestive system. The tongues ​​were removed for ex situ macroscopic and morphometric analyses, as well as for light microscopy and scanning electron microscopy, of fragments of the different lingual regions. The tongue of L. pardalis had an elongated form that was subdivided into the apex, body and root, in which four papillary types were observed: filiform, fungiform, circumvallate and conical. It presented with a stratified, keratinized squamous epithelium, followed by loose and dense connective tissues, as well as a skeletal striated musculature that comprised most of the organ. In addition, in scanning electron microscopy the filiform papillae showed a complex with multiple layers of keratin with triangular shape projected caudally in oral cavity. The fungiform papillae were distributed among the filiform and showed a rounded shape with some gustatory pores, and are keratinized but in a lower intensity if compared with filiform. The vallate papillae, located in lingual root, showed an oval format, had a deep groove surrounded the papillae and some gustatory pores. The conical papillae are located in lingual root and are similar to the filiform. The tongue of L. pardalis resembles other carnivorous species, mainly among felids. However, it differed in relation to the quantity of vallate papillae and the absence of foliate papillae., (© 2019 Blackwell Verlag GmbH.)

A macroscopic and microscopic study of the mandibular organ of the silky anteater (Cyclopes didactylus) was carried out. The organ extends from below the zygomatic bone line to the middle of the mandible body, between the skin and the masseter muscle, on both sides of the animal. It has an average length of 11.7 mm and a width of 6.3 mm. In the mesoscopic analysis, it was observed that the organ presents in yellowish color due to the high amount of sebaceous content. In the histological analysis, the mandibular organ was observed to be composed of innumerable alveoli of the specialized sebaceous gland, surrounded by a layer of adventitia tunica. Scanning electron microscopy (SEM), revealed an apparent alveolar division with what appeared to be a sulcus at its center. The information here presented regarding the constitution and location of this structure has not been previously explored for other species and differs with respect to other descriptions for anteaters. Based on the present study, it is suggested that the mandibular organ is involved in social interaction in this species., (© 2019 Wiley Periodicals, Inc.)

This study compared the structure of helminth parasite communities in two populations of Astronotus ocellatus from two localities in Pará State, eastern Amazon (Brazil). Hosts from the Tapajós River were infected by Posthodiplostomum sp. metacercarie, larvae of Contracaecum sp. and Pseudoproleptus sp., with predominance of Contracaecum sp. Hosts from Iara Lake were infected by Procamallanus spiculastriatus, Proteocephalus sp. and Acanthocephala gen. sp., with predominance of P. spiculastriatus. Parasites had an aggregated dispersion and there were differences in Shannon diversity index and the evenness between both host populations, because the parasite component community showed no similarity. The existence of variation in infracommunity and community of parasites for A. ocellatus from different localities indicates the presence of an uneven distribution in terms of species and density of parasites, as well as of intermediate hosts in the localities surveyed.

The coccidians of the family Calyptosporidae are parasites of the tissue and organs of fish and aquatic invertebrates, in particular in the tropical region. In contrast with other apicomplexans of the suborder Eimeriorina, the diversity and ecology of the species of the genus Calyptospora have been poorly investigated, resulting in a lacuna that restricts the understanding of the distribution and prevalence of this group of eukaryote microparasites in the Amazon region. In the present study, the integrated comparative analysis of morphological characteristics, histological and structural traits, and the sequences of a fragment of the 18S rRNA gene, provides support for the identification of a new species of Calyptospora, found parasitizing the hepatic tissue of the piscivorous blue peacock bass, Cichla piquiti, captured in the reservoir of the Estreito hydroelectric dam on the middle Tocantins River in northern Brazil. This new species was named Calyptospora paranaidji n. sp., (© 2018 International Society of Protistologists.)

Dipetalonema caudispina (Molin, 1858) and D. gracile (Rudolphi, 1809) (Filarioidea: Onchocercidae) are two of six known species of filarial nematodes that parasitize Neotropical non-human primates. Adult filariae were collected from the thoracic and abdominal cavities of 38 of 44 specimens of Sapajus macrocephalus (Spix, 1823) and nine of ten specimens of Cebus albifrons (Humboldt, 1812) (Primates: Cebidae), distributed in the Yavarí-Mirín river basin and used locally for human consumption. Co-occurrence of D. caudispina and D. gracile is reported for the first time, with a prevalence of 18.5% (10 of 54 hosts examined). Our finding of D. caudispina and D. gracile in cebids from the Peruvian Amazon constitutes a new geographical record for both filariae, two new host records for D. caudispina, and the first report of D. gracile in S. macrocephalus. In addition, we provide morphometric data for D. caudispina, complementing the original description, as well as scanning electron microscopy details on the structure of the area rugosa and number of caudal papillae in males.

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.

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.

A new species of Procamallanus Baylis, 1923 was found as a parasite of the fish Astronotusocellatus (Agassiz, 1831) from a lake in the Jardim Botânico Bosque Rodrigues Alves, Belém, Brazil. Procamallanusspiculastriatus sp. n. has a smooth buccal capsule and a well-developed basal ring that is armed with four sclerotized tooth-like structures. The male of the new species is similar to the two species that are known from Brazilian fish, P.peraccuratus Pinto, Fábio, Noronha & Rolas, 1976, and P.annipetterae Kohn & Fernandes, 1988, by the absence of the gubernaculum. It differs from these two by the morphology of the buccal capsule, the number are arrangement of the caudal papillae in males, the size and morphology of the spicules and the shape of the tail of both sexes. Procamallanusspiculastriatus sp. n. is the third species discovered in fish from Brazil. This finding extends the geographical distribution of the genus into the Brazilian Amazon.

Studies of helminths in road-killed wild animals are still uncommon but may provide promising results since they can identify the parasites in juvenile and adult hosts and meet the recommendations of current discussions on bioethics that prioritize alternative methods for the use of animals. This study evaluated three Cerdocyon thous individuals that were donated after dying from being run over. Two of them had small nematode adults in the epithelial and connective tissues of the tongue. The diagnosis was based on the presence of eggs, observed in histological sections, and morphological characteristics of the nematodes in the tongue. Morphologically, this nematode has a body with transverse grooves, simple mouth opening and no lips, esophagus and stichosome with stichocytes and bacillary bands along the body, which is characteristic morphology of the family Capilariidae and genus Capillaria . The presence of this nematode in the tongue of C. thous is an extremely important fact that contributes to what is known about the biodiversity of zoonotic parasites in wild canid populations. However, an explanation for these findings remains unclear because, until now, this has not been observed in the biological cycle of the species.