Luiz Eduardo Roland Tavares

Studies on nematodes in Brazilian fishes began with the description of Trichocephalus gibbosus (currently Oncophora melanocephala) by Rudolphi (1819), based on specimens collected from Thunnus thyn...

Fleshy fruits are a key resource for many terrestrial and aquatic animals, especially in tropical rainforests and rivers. Frugivory is well documented as a fundamental interaction between plants and animals, contributing to seed dispersal and the maintenance of biological diversity. Although fruit falling from riparian plants plays important roles in aquatic resource inputs, these ecosystem processes are not widely studied which can lead to geographical and functional trait biases. We demonstrated this gap of information in a literature survey using a bibliographical analysis. We found clear geographical biases towards more frequent studies in the Americas, especially in Brazil, and shortfalls in other tropical areas, such as Asian and African tropical regions. In contrast, studies on fruit-animal interaction in tropical terrestrial ecosystems are far more frequent than those in aquatic ecosystems. Some approaches and concepts originally developed for terrestrial studies can be applied to tropical freshwater and marine ecosystems, offering new insights into their functioning. This integration can foster a more comprehensive understanding of terrestrial–aquatic linkages while promoting greater collaboration and equity in research partnerships.

Species of Micropleura Linstow, 1906 (Dracunculoidea: Nematoda) are common parasites of crocodilians worldwide. Studies related to this genus remain scarce, particularly regarding genetic characterizations, due to the difficulty in obtaining the parasite specimens. Although the morphology of M . vazi Travassos, 1933, a parasite of Caiman spp. in the Neotropics, has been previously evaluated, some morphological inconsistencies persist, and certain features are insufficiently described. Moreover, there is no genetic data for the species. In this regard, we provide the first genetic characterization of M . vazi along with detailed morphological analysis using light and scanning electron microscopy (SEM). We report for the first time in M . vazi the presence of phasmids and of oesophageal gland nuclei, in addition to provide a clearer view of the cephalic region and the accurate position of the vulva. Genetic characterization of the species was conducted using partial sequences of the 18S and 28S rDNA, and the phylogenetic reconstructions using these first indicated the monophyly of Micropleura and of most families within Dracunculoidea. Moreover, Micropleuridae appears to be the sister group to Dracunculidae, and Philonematidae should be considered valid as it is not close to Philometridae. Furthermore, Anguillicolidae should be allocated in another superfamily, Anguillicoloidea, which is basal relative to Dracunculoidea and far from it. The absence of males in the current sampling may suggest a seasonal occurrence of these parasites, as has been reported for other dracunculoid nematodes.

Purpose: Oswaldofilaria bacillaris is the type species of the genus, but its morphology remains little known and partially contradictory. Moreover, there are no genetic data and scanning electron microscopical observations on the species, like in most Oswaldofilaria spp. The phylogenetic relationships among Oswaldofilaria spp. are practically unknown. This study aimed to evaluate the detailed morphology of O . bacillaris , provide its first genetic characterization, and discuss the phylogenetic relationships within Oswaldofilaria . Methods: Parasites infecting the body cavity of Caiman yacare in Pantanal wetlands, Mato Grosso do Sul, Brazil, were collected and processed for morphological studies using light and scanning electron microscopy. Genetic characterization was based on partial sequences of 18S and 28S rDNA. A phylogeny was reconstructed based on 28S sequences including all Oswaldofilaria available. Results: Nematodes were assigned to O . bacillaris mainly based on the oral opening markedly displaced ventrally. Males had seven pairs of caudal papillae encircling the cloaca, and their two most posterior pairs were hardly visible, which is also characteristic in other congeners. Moreover, a delicate area rugosa previously unreported in the species was observed. Oswaldofilaria bacillaris formed a monophyletic assemblage with the congeners, being sister to O . chabaudi , and O . petersi was basal, these last two parasites of lizards. Conclusion: The present findings strengthened the specific diagnosis of O . bacillaris and elucidated the morphological contradictions. The phylogeny reinforced the hypotheses that Oswaldofilaria emerged in lizards and colonized crocodilians by host switch, and reduction in number of caudal papillae in males is a derived feature.

The diversity of Rhabdias includes 101 species, 71 of which parasitize the lungs of anurans, caudates, gymnophionans, and some occur in reptiles worldwide. Currently, 26 species are found in the Neotropical region, and in Brazil, there are 16 nominal species, a relatively low number considering the high diversity of potential hosts. Here, we describe a new species of Rhabdias found in Physalaemus albonotatus , with morphological and molecular data, as well as phylogenetic analyses using sequences of the mitochondrial gene Cytochrome Oxidase Subunit I (COI). Rhabdias taquariensis n. sp. differs from other known species by a set of morphometric traits and by presenting a well-defined internal shape of the cephalic dilation. Molecular analyses revealed that R. taquariensis n. sp. exhibits a significant divergence of 13.6% in COI compared to the Rhabdias cf. stenocephala species complex. Additionally, phylogenetic reconstructions indicate that the new species represents a distinct lineage, external to a clade formed by species such as Rhabdias fuelleborni , Rhabdias cf. stenocephala , and Rhabdias waiapi. Rhabdias taquariensis n. sp. is the 27th species described in the Neotropical region and the 16th in Brazil, the first description of a species of the genus Rhabdias for Physalaemus albonotatus , and one of the few Rhabdias species described for the Cerrado biome.

Purpose In this study, 143 lutjanid fishes representing four different species from the Northeast coast off Brazil were analyzed for parasites. The aim of the present study is to provide a detailed redescription of R. (I.) vicentei, collected from lutjanid fishes in Brazil, including the first observation of the species using scanning electron microscopy (SEM). Methods Nematodes found clarified in a crescent glycerin series, were photographed and measured (in mm), and some specimens destined for SEM. The Illustrations were made using an optical microscope with a drawing tube. Results Nematodes found were identified as Raphidascaris (Ichthyascaris) vicentei, infecting 6.29% of the examined fish. Detailed morphological analysis revealed the following characteristics observed for the first time in this species: labial papillae, narrow lateral alae and the detailed structure of male spicules. These contributions help filling the gaps in the literature and expand the knowledge of this parasite morphology. Conclusions The presence of R. (I.) vicentei in four lutjanid species may indicates low host specificity, highlighting its adaptability to different hosts. Furthermore, new host records are given. This research provides the most comprehensive morphological description of R. (I.) vicentei to date, generating crucial insights for a better understanding of the parasitic biodiversity off the Brazilian Northeastern coast of Brazil, as well as establishing foundation for future investigations on the ecology and impacts of these parasites in fish populations from this region.

(1) Background: Although Physaloptera retusa is one of the most widespread species infecting reptiles in the Americas, numerous taxonomic problems and little genetic data are associated with it. To clarify the taxonomy of this species, we used an integrative approach. (2) Methods: Physaloptera retusa-infecting Erythrolamprus typhlus (snake) from the Pantanal wetlands, Brazil, was morphologically and genetically characterised (18S and 28S rDNA; COI mtDNA) and compared with conspecific sequences available in GenBank, from parasites of Tupinambis teguixin (lizard), using species delimitation methods. Type specimens of P. liophis were re-evaluated given its morphological similarities with P. retusa. (3) Results: The morphology of the present specimens was equal to that of P. retusa, in which the only difference from P. liophis was the relative position of the vulva. Species delimitation methods were more accurate for the COI dataset; all of them (except ABGD) indicated interspecificity among P. retusa sequences. However, a lack of morphological data or voucher material, associated with the deposited sequences, prevented more assertive conclusions. (4) Conclusions: The present results highlight the importance of a clear association between genetic data and morphology of the isolation source, or at least its adequate vouchering. Moreover, P. retusa may represent a species complex in cryptic speciation, since it is widespread and has low hosts specificity.

The teiid Ameiva ameiva is commonly found in natural or anthropized open environments throughout South America, part of Central America and Florida, whereit was introduced. As A. ameiva has a wide range and common occurrence, several reports of predation events on this teiid are available in the literature. However, only a few predation records of A. ameiva were reported in a review on predators of Squamata considered a limited source of data. In this paper we documented the predation of the Savanna hawk Heterospizias meridionalis on a specimen of A. ameiva in southeastern Brazil. In addition, we updated the list of predators of A. ameiva, seeking to determine if there is any specific group of predators that exert greater pressure on this lizard. We found only two records of predation by H. meridionalis on A. ameiva, in Suriname and in Costa Rica respectively. Thus, we report the predatory interaction between H. meridionalis and A. ameiva in Brazil for the first time. In our review, we found 111 records of predation of A. ameiva distributed in six countries and identified 61 species of vertebrates and one of invertebrates as predators. Among vertebrates, the highest number of species was recorded for reptiles (32 species), followed by birds (15 species), mammals (13 species) and amphibians (one species). Snakes constituted the main group of predators of A. ameiva. Furthermore, we found 47 species not previously listed, increasing the predator richness to 62 species.

Parasitic otitis in cattle, caused by mites, has been reported from several continents. The present study aimed to determine the distribution, prevalence, intensity, mean intensity, and range of the agent in cattle in the state of Mato Grosso do Sul, Brazil. The samples were designed at random, with an acceptable margin of error of 3% and a confidence interval of 99%. A total of 449 animals were sampled immediately after slaughter from 34 different municipalities in the state using the technique of flushing both ear canals. Only Raillietia auris (Leidy, 1872) were found, with a prevalence of 98.6%, mean intensity of 53.78 mites/animal, and a range of 1-323. Impressively, the prevalence found was identical to another survey carried out 39 years ago in the same region. Details about the parasite intensity in different age categories of the animals are presented. The study demonstrates that the prevalence and intensity of infestation by Raillietia auris are high, and in older cattle are higher than young ones.

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