Aortic branches and rete mirabile of the limbs of two-toed sloth (Choloepus didactylus).

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.

Morphological identification of Skrjabinisakis Mozgovoi, 1951 (Nematoda: Anisakidae) in Kogia sima (Cetacea: Kogiidae) from Brazilian waters.

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.

Ozolaimus megatyphlon and Ozolaimus cirratus parasitizing the Iguana iguana (Linnaeus, 1758) from Marajó Island, Pará, Brasil: new occurrence and morphological redescription.

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.

A new nematode of the family Capillariidae identified in Cairina moschata (Linnaeus) on Marajó Island in the Brazilian Amazon.

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.

Urogenital development and sexual differentiation in males of the species Dasyprocta fuliginosa.

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.

Redescription of Brevimulticaecum baylisi () (Nematoda: Heterocheilidae), a parasite of Caiman crocodilus (Crocodylia: Alligatoridae) in the north-eastern Peruvian 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.

Systematic and parasite-host relationship by Baruscapillaria appendiculata in Phalacrocorax brasilianus collected from Marajó Island, State of Pará, Brazil.

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 Nasincová, 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.

Morphological and molecular characterization of Contracaecum australe (Nematoda: Anisakidae) parasitizing Phalacrocorax brasilianus (Aves: Phalacrocoracidae) on the north coast of Brazil.

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.

Spirocamallanus delirae n. sp. (Nematoda, Camallanidae), a parasite of Propimelodus eigenmanni (Siluriformes: Pimelodidae) from the Brazilian Amazon.

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.

Revisiting the taxonomy of Rhabdias fuelleborni Travassos, 1928 (Nematoda, Rhabdiasidae) with approaches to delimitation of species and notes on molecular phylogeny.

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.

Integrative taxonomy in the genus Rhabdias Stiles et Hassall, 1905 from anuran in Brazil, description of two new species and phylogenetic analyses.

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.

Morphological identification of Skrjabinisakis Mozgovoi, 1951 (Nematoda: Anisakidae) in Kogia sima (Cetacea: Kogiidae) from Brazilian waters / Identificação morfológica de Skrjabinisakis Mozgovoi, 1951 (Nematoda: Anisakidae) em Kogia sima (Cetacea: Kogiidae) em águas brasileiras

Abstract 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.

Resumo São apresentados, neste trabalho, novos dados morfológicos, morfométricos e de microscopia eletrônica de varredura de um nematoide da família Anisakidae, recuperado de Kogia sima, um cetáceo que veio a óbito na costa norte do Brasil. Características morfológicas, como o ventrículo em forma de violino, espículos curtos e iguais, além da distribuição de papilas pós-cloacais e especificidade pelo hospedeiro definitivo (cetáceos Kogiidae) demonstram similaridade a Skrjabinisakis paggiae. Esta pesquisa registra Kogia sima e S. paggiae na costa estuarina paraense, norte do Brasil.

A new species of Huffmanela (Nematoda: Trichosomoididae) parasitizing Colomesus psittacus (Tetraodontiformes) from Marajó Island, Pará State, Brazil.

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.

Comparative morphology of the paw pad of the main arboreal Xenarthras from Amazon.

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.

Morphology of the male reproductive tract of Eira barbara.

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.

Ocular microscopy of Bradypus variegatus.

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.

A new species of Huffmanela (Nematoda: Trichosomoididae) parasitizing Colomesus psittacus (Tetraodontiformes) from Marajó Island, Pará State, Brazil / Uma nova espécie de Huffmanela (Nematoda: Trichosomoididae) parasitando Colomesus psittacus (Tetraodontiformes) da Ilha de Marajó, Pará, Brasil

Abstract 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.

Resumo O baiacu amazônico Colomesus psittacus é um peixe de importância comercial para a aquariofilia, além de ser capturado como bycacth e descartado morto no ambiente nas pescarias artesanais que ocorrem nos estuários da região Norte do Brasil. Nesse sentido, objetivou-se identificar e descrever nematódeos do gênero Huffmanela em baiacus oriundos da ilha de Marajó, bem como as alterações histopatológicas causadas por eles. Cinquenta e cinco peixes foram analisados, e trinta e cinco espécimes apresentaram o parasita nas branquias. Características morfológicas sugerem tratar-se de uma nova espécie do gênero Huffmanela, e os exames histopatológicos demonstraram uma inflamação edematosa na lamela secundária e presença de ovos desse nematódeo. Esse fato se torna o primeiro registro desse gênero parasito em C. psittacus no Brasil.

Diversity of endohelminths parasitizing bred Muscovy ducks Cairina moschata domestica (Anseriformes: Anatidae) from the eastern Brazilian Amazon.

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.

Spirocamallanus krameri and Contracaecum sp. thirdstage larvae (Nematoda) in Hoplerythrinus unitaeniatus (Erythrinidae) of eastern Amazon (Brazil).

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.

Globocephalus urosubulatus (Alessandrini, 1909) (Nematoda: Ancylostomatidae) in Brazil: a morphological revisitation.

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.