Morphological description of the digestive tract of the Amazonian Diving Lizard Uranoscodon superciliosus (Linnaeus, 1758) and its associations to the diet and foraging mode.

The study aimed to characterize the digestive tract of Uranoscodon superciliosus and its associations to the diet and foraging behavior already described for the species. Five lizards were captured in forest areas near the city of Manaus, Amazonas, Brazil. Tongue, oesophagus, stomach, small and large intestines fragments were collected, fixed, and processed for light microscopy. Hyaline cartilage was present in the center of the tongue, and the papillae from the apex and glands from the radix showed positive reaction to Alcian blue. The oesophagus presented a folded mucosa, covered by an epithelium with mucous and goblet cells positive to PAS and Alcian blue. There was presence of gastric glands in the cardic and fundic stomach regions, plus all the regions reacted positively to PAS. Fold and villi variations in both small and large intestine were noted, as well as the number and arrangement of goblet cells. Mucous and goblet cells from the small intestine were positively stained in PAS, while only the goblet cells were Alcian blue positive. These findings indicate that the Amazonian Diving Lizard's digestive tract organs, mainly the tongue and stomach, present morphologies associated to ambush-type foraging and a specific diet largely based on small invertebrates.

Hepatozoon Miller, 1908 parasites in the Colubridae snakes Clelia clelia (Daudin, 1803) and Drymarchon corais (Boie, 1827) from the Eastern Amazonia.

Based on the genetic, morphological, and morphometric data of blood gamonts, we identified Hepatozoon parasites in colubrid snakes sampled in the Eastern Amazon region. Hepatozoon trigeminum was detected in the mussurana snake Clelia clelia and exhibited wide and elongated gamonts (mean dimensions: 14.25±0.65 × 4.31±0.43 µm) with an evident parasitophorous vacuole. Hepatozoon odwyerae sp. nov. was described in the indigo snake Drymarchon corais, whose gamonts have elongated and thin bodies (mean dimensions: 13.41±0.79 × 3.72±0.35 µm) with one end more tapered than the other. Phylogenetic analyses, based on the amplification of a 441 bp fragment of the 18S rRNA gene, revealed that the novel sequences of Hepatozoon spp. from our study were closely related to hemogregarine lineages found in lizards and snakes from Brazil, forming a well-supported monophyletic clade with them. The present study provides the first species description of Hepatoozon in D. corais and a new record of a host species for C. clelia using the integrated taxonomic data. We also highlight the importance of further investigations into the diversity of Hepatozoon in snakes, a rich but underestimated group of parasites, especially in the Amazonian biome.

Hepatozoon parasites (Apicomplexa: Hepatozoidae) in fish Hoplias aimara (Characiformes, Erythrinidae) from the Eastern Amazon, Brazil.

This study reports the occurrence of parasites belonging to the Hepatozoon genus in fish Hoplias aimara from the Eastern Amazon. Fish (n = 54) were sampled from the Falsino River, located in the Amapá National Forest (FLONA), in the state of Amapá, northern Brazil. Fresh liver preparations were examined in the field between a slide and a coverslip under a light microscope. Cysts containing Hepatozoon cystozoites were observed in the liver of 5 (9%) out of 54 H. aimara individuals. The cysts were ovoid (mean dimensions 10.28 × 9.8 µm), presenting up to four elongated cystozoites (mean dimensions 11.04 × 1.68 µm), containing 1 to 4 residual bodies of different sizes. A single liver sample containing cysts was submitted to DNA extraction and PCR analyses based on a fragment of the 18S rRNA gene. The sequencing revealed a 465 bp fragment exhibiting 99% query coverage, 0.0 E-value, and 98.7% identity with Hepatozoon caimani (MF322538 and MF322539), detected in caimans (Caiman yacare) from Brazil. This is the first report of the occurrence of cysts containing Hepatozoon cystozoites in free-living fishes.

Phylogenetic analysis of chelonian hemogregarines reveals shared species among the Amazonian freshwater turtle Podocnemis spp. and provides a description of two new species of Haemogregarina.

This study describes two new species of the genus Haemogregarina living in the Amazonian freshwater turtles Podocnemis expansa and Podocnemis sextuberculata. Haemogregarina species isolated from P. expansa have been characterized by the presence of encapsulated, folded immature gamonts, with the parasitophorous vacuole and fragmented chromatin located in the central region. In Haemogregarina found in P. sextuberculata, curved immature gamonts were observed inside a parasitophorous vacuole, with small, slightly arched meronts with rounded nuclei, and mature gamonts with trapezoid-shaped condensed nuclei. The novel 18S rRNA sequences obtained in this study clustered within a well-supported clade composed of hemogregarines isolated from other neotropical freshwater turtles from the families Podocnemididae and Geoemydidae. The hemogregarines found in this study were compared to Haemogregarina podocnemis from Podocnemis unifilis and Haemogregarina sp. from Podocnemis expansa, based on morphological, morphometric, and molecular data. The analysis supports the new species Haemogregarina karaja sp. nov. isolated from P. expansa and Haemogregarina embaubali sp. nov. found in P. sextuberculata.

Ticks on reptiles and amphibians in Central Amazonia, with notes on rickettsial infections.

Reptiles and amphibians are exceptional hosts for different ectoparasites, including mites and ticks. In this study, we investigated tick infestations on reptiles and amphibians trapped in Central Amazonia, and also assessed the presence of rickettsial infections in the collected ticks. From September 2016 to September 2019, 385 reptiles (350 lizards, 20 snakes, 12 tortoises, and three caimans) and 120 amphibians (119 anurans and one caecilian) were captured and examined for ectoparasites. Overall, 35 (10%) lizards, three (25%) tortoises and one (0.8%) toad were parasitized by ticks (124 larvae, 32 nymphs, and 22 adults). In lizards, tick infestation varied significantly according to landscape category and age group. Based on combined morphological and molecular analyses, these ticks were identified as Amblyomma humerale (14 larvae, 12 nymphs, 19 males, and one female), Amblyomma nodosum (three larvae, one nymph, and one female), and Amblyomma rotundatum (four larvae, three nymphs, and one female), and Amblyomma spp. (103 larvae and 16 nymphs). Our study presents the first records of A. nodosum in the Amazonas state and suggests that teiid lizards are important hosts for larvae and nymphs of A. humerale in Central Amazonia. Moreover, a nymph of A. humerale collected from a common tegu (Tupinambis teguixin) was found positive for Rickettsia amblyommatis, which agrees with previous reports, suggesting that the A. humerale-R. amblyommatis relationship may be more common than currently recognized.

Hepatozoon cevapii (Apicomplexa: Hepatozoidae) in the Thamnodynastes lanei snake (Colubridae, Tachymenini) from the Eastern Amazon, Brazil.

The aim of the present study was to verify the occurrence of hemogregarines in the colubrid snake Thamnodynastes lanei from the eastern Amazon region of Brazil. Intraerythrocytic gamonts with mean dimensions of 14.8 ± 1.8 × 4.0 ± 0.7 µm and encapsulated gamonts with mean dimensions of 15.3 ± 1.1 × 4.8 ± 0.5 µm were observed. Through morphological and molecular data based on the partial 18S rDNA gene, the parasite was identified as Hepatozoon cevapii, originally described in the viperid snake Crotalus durissus terrificus from the southeast region of Brazil. Thus, the findings of the present study extend the geographic range of H. cevapii and provide novel Hepatozoon-snake associations.

Redescription of Hepatozoon ameivae (Carini and Rudolph, 1912) from the lizard Ameiva ameiva (Linnaeus, 1758).

Blood samples from 72 Ameiva ameiva lizards from Central Amazonian upland forests were collected, and thin smears of 40 (55.5%) animals were positive for gamonts of Hepatozoon with a mean level of intensity of infection of 14 parasites/2000 blood erythrocytes (0.73%). The gametocytes were found attached with host cells' nuclei, and their dimensions were 14.28 ± 1.05 µm in length and 4.50 ± 0.80 µm in width. Phylogenetic analyses of the 18S rRNA gene showed that the new sequences obtained from A. ameiva constitute a monophyletic sister clade to the Hepatozoon spp. from Brazilian snakes. Based on morphological features and new molecular data, we redescribe this hemogregarine as Hepatozoon ameivae. This study also provides the first molecular characterization of a Hepatozoon species from a Brazilian lizard.

Prevalence and parasitemia of Haemogregarina sp. in Podocnemis expansa (Testudines: Podocnemididae) from the Brazilian Amazon.

Seventy-five turtles Podocnemis expansa in the Brazilian Amazon were examined for the presence of ectoparasites and hemoparasites. Samplings were performed in three study areas in the state of Tocantins, Brazil. Twenty-five specimens were sampled per study area (a commercial breeding facility, an indigenous subsistence breeding facility and a wild population of the Javaés River). Hemoparasites of the genus Haemogregarina were found in 66% (50/75) of the turtle specimens, and the infections were restricted to the commercial breeding facility and to the wild population of the Javaés River. The mean level of parasitemia was 54/2,000 erythrocytes (2%). There was no correlation between the body condition index of the chelonians and the level of parasitemia, with no significant difference between genders. No leeches were observed during the physical exams in any of the study areas, but the specimens from the commercial breeding facility were in poor physical condition with shell deformities and the presence of a relatively high amount of skin ulcerations, most likely caused by fungi and bacteria. This was the first study to record the occurrence of hemogregarines on a population scale in P. expansa and helps to increase knowledge about hemoparasites in chelonians in Brazil.

Prevalence and parasitemia of Haemogregarina sp. in Podocnemis expansa (Testudines: Podocnemididae) from the Brazilian Amazon / Prevalência e parasitemia de Haemogregarina sp. em Podocnemis expansa (Testudines: Podocnemididae) da Amazônia Brasileira

Seventy-five turtles Podocnemis expansa in the Brazilian Amazon were examined for the presence of ectoparasites and hemoparasites. Samplings were performed in three study areas in the state of Tocantins, Brazil. Twenty-five specimens were sampled per study area (a commercial breeding facility, an indigenous subsistence breeding facility and a wild population of the Javaés River). Hemoparasites of the genus Haemogregarina were found in 66% (50/75) of the turtle specimens, and the infections were restricted to the commercial breeding facility and to the wild population of the Javaés River. The mean level of parasitemia was 54/2,000 erythrocytes (2%). There was no correlation between the body condition index of the chelonians and the level of parasitemia, with no significant difference between genders. No leeches were observed during the physical exams in any of the study areas, but the specimens from the commercial breeding facility were in poor physical condition with shell deformities and the presence of a relatively high amount of skin ulcerations, most likely caused by fungi and bacteria. This was the first study to record the occurrence of hemogregarines on a population scale in P. expansa and helps to increase knowledge about hemoparasites in chelonians in Brazil.

Setenta e cinco tartarugas Podocnemis expansa foram examinadas para a presença de ectoparasitos e hemoparasitos na região amazônica brasileira. As coletas foram realizadas no Estado do Tocantins, Brasil. No estudo foram amostrados 25 indivíduos por local, um criatório comercial, um criatório de subsistência indígena e uma população silvestre do rio Javaés. Foram encontrados hemoparasitos pertencentes ao gênero Haemogregarina em 66% (50/75) dos animais, sendo que as infecções foram restritas ao criatório comercial e a população silvestre do rio Javaés. A parasitemia média foi de 54/2.000 eritrócitos (2%). Não houve relação entre o índice de condição corporal dos quelônios e os níveis de parasitemia e nem diferença quanto ao sexo dos animais. Não foram observadas sanguessugas durante os exames físicos, porém os animais do criatório comercial apresentaram condições físicas ruins com deformidades no casco e presença de uma quantidade relativamente alta de ulcerações na pele, provavelmente causadas por fungos ou bactérias. Este estudo registrou a primeira ocorrência de hemogregarinas em uma escala populacional de P. expansa e contribui para expandir o conhecimento de hemoparasitos em quelônios no Brasil.