Enzo Emmerich

Ochetosoma heterocoelium (Travassos, 1921) was collected from the mouth and oesophagus of a pit viper, Bothrops moojeni Hoge, 1966 in São Sebastião do Paraíso Farm (21°51’48.26" S, 48°26’56.78" W), municipality of Boa Esperança do Sul, São Paulo State, Brazil. In this study, we provide the first molecular characterisation of this digenean using 28S rDNA and COI sequences, and its phylogenetic position within the Plagiorchiida is assessed. Furthermore, new morphological features are added to the diagnosis of the species, and scanning electron microscopy photomicrographs are presented. Sequences of the 28S rRNA gene of O. heterocoelium were successfully obtained and aligned with 35 digenean species belonging to Plagiorchiida. Only three congeners – O. aniarum (Leidy, 1890), O elongatum (Seo et al. 2024), and O. kansense (Crow, 1913) – have been sequenced for this molecular marker. The newly sequenced individuals of O. heterocoelium are 98.7% and 99.4% similar to O. aniarum and O. kansensis, respectively, and Ochetosoma is not recovered as a monophyletic group. Dasymetra nicolli Holl and Allison, 1935 and Lechriorchis tygarti Talbot, 1933 are nested with Ochetosoma.

Purpose Brazilian anurans are considered the most diverse and species rich around the world. Although in recent years there has been a strong focus on research related to this group of animals, their parasites have not received the same attention. Thus, this study aimed to provide morphological and molecular data on haemogregarines biodiversity infecting Brazilian anurans. Methods During 2020, 116 anurans were collected from four Brazilian States and their blood and fragment of organs were screened for haemogregarine parasites. Results From the total, seven (6.03%) animals were found infected with species of Hepatozoon and Dactylosoma. Based on the morphological and molecular analysis, four anurans were found infected with Hepatozoon latrensis. The phylogenetic analysis has shown the isolates from this study grouping with the Brazilian anuran Hepatozoon clade, also with gene similarity ranging from 99.70 to 100% to H. latrensis isolates available on GenBank. Furthermore, three specimens (Trachycephalus typhonius, Leptodactylus latrans, and Rhinella diptycha) were infected with the same species of Dactylosoma (100% genetic similarity), with a genetic similarity of 98.56% to Dactylosoma piperis the only other species described in Brazil. In support of the molecular data, different morphological characters were observed in the blood smears as compared to D. piperis, suggesting that the species of Dactylosoma from the present study infecting three different species of Brazilian anurans is an undescribed species. Conclusion Thus, this study increases the knowledge of Brazilian anuran blood parasites and demonstrates the importance of using integrative approaches for the diagnosis of haemoparasites.

Cosmocerca spp. are common nematode parasites of amphibians. We provide herein molecular data for two species of Cosmocerca and describe a new species, Cosmocerca albopunctata n. sp., using light microscopy and molecular data (cytochrome c oxidase subunit 1 – COI mtDNA). Cosmocerca albopunctata n. sp. can be easily distinguished from other congeneric species by the combination of characteristics such as body size, length of spicules and gubernaculum, and the arrangements and number of caudal papillae (7 + 1:1 + 1:6). The phylogenetic results based on the partial COI mtDNA sequences clustered the new species in a monophyletic clade along with the other sequences of Cosmocerca spp. Therefore, our results contribute to the knowledge about the species diversity and genetic data for Cosmocerca spp. in the Neotropical region.

During a parasite survey in Brazilian amphibians from São Paulo state, Brazil, Gorgoderina parvicava Travassos, 1922 was found in the urinary bladder (11 adult worms) and (five juvenile worms) in the kidneys of the pepper-frog Leptodactylus labyrinthicus (Spix, 1824). Parasites were examined by microscopy and 28S rDNA and COI gene were sequenced and analyzed for the molecular study. The phylogenetic reconstructions resulted in identical topologies with highly supported values in the nodes in most clades using Maximum likelihood and Bayesian inference methods and positioned G. parvicava in the subclade formed by species of subfamily Gorgoderinae parasitizing the urinary bladder of amphibians. Molecular phylogenetic data showed that this species is related to other species of Gorgoderina. In addition, new molecular data and the analyses of genetic distances provide extra comparative data, which can be applied in further investigations on the taxonomic status and the diversity among Gorgoderina spp. and host-parasite relationships.

A new nematode species, Rhabdochona (Rhabdochona) fuscovaria sp. n. (Rhabdochonidae), is described based on specimens collected from the stomach of the snouted treefrog Scinax fuscovarius (Hylidae) in the São Sebastião do Paraíso farm, municipality of Boa Esperança do Sul, southeastern Brazil. This species is characterized by deirids small, simple and stylet shaped, prostom funnel-shaped with 14 teeth, conspicuous left spicule (585.7 µm), distal tip slightly widened, moderately dilated, right spicule (132.9 µm), boat-shaped, without dorsal barb at the distal tip, 18 pairs of caudal papillae (9 pairs precloacal and 9 pairs postcloacal), and nonfilamented eggs. This is the fourth species described for South America and the 13th for the Neotropical Region.

Purpose Species of Hepatozoon Miller, 1908 (Hepatozoidae) are blood protozoans with a cosmopolitan distribution and are reported to parasitize a range of vertebrate hosts including mammals, birds, reptiles, and amphibians. The present study aimed to describe a new species of Hepatozoon (Apicomplexa: Adeleorina: Hepatozoidae) found infecting the sleep snake Dipsas mikanii (Schlegel, 1837) (Squamata: Colubridae: Dipsadinae). Methods The snake was collected in 2017 at the municipality of Britânia, Goiás State, Brazil. Blood smears were made in order to find blood gametocytes and PCR was performed targeting the 18S rRNA gene. Results Microscopy screening of blood smears revealed the presence of intraerythrocytic gamont stages of Hepatozoon sp. in the peripheral blood with a parasitemia of 0.25%. Furthermore, meronts and monozoic cysts were observed in histological sections of the liver from the infected individual. The interspecific divergence of 18S rRNA sequences fragments isolated from D. mikanii had differences (2.39–11.3%) as compared to other sequences of species of Hepatozoon from snakes. Conclusions Based on morphological and molecular data, a new species of Hepatozoon infecting D. mikanii from Brazil is described.

Two digenean species, Infidum infidum Faria, 1910 (Dicrocoeliidae) and Travtrema stenocotyle Cohn, 1902 (Plagiorchiidae), were collected in the large pit viper Bothrops moojeni Hoge, 1966 from Reserva Particular do Patrimônio Natural Cisalpina, municipality of Brasilândia, Mato Grosso do Sul State, Brazil. In this study, we provide the first molecular characterisation using the 28S rDNA and phylogenetic position data of these two common digeneans from B. moojeni. The molecular framework revealed topologies with strongly supported clades using maximum likelihood and Bayesian inference methods, positioned I. infidum among Plagiorchiidae and not among Dicrocoeliidae as expected and T. stenocotyle (Plagiorchiidae) surprisingly grouped as a sister group to Allassogonoporidae, Microphallidae, Pleurogenidae, and Prosthogonimidae, not related to plagiorchids. Our molecular phylogenetic data showed that these species may not correspond to their assigned families and encourage future studies on the systematic of these understudied groups.