Navegando por Assunto "Anuros"

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Acesso aberto (Open Access)
Diversidade de helmintos parasitos de uma população de Osteocephalus cabrerai (Anura: Hylidae) na Amazônia brasileira
(Universidade Federal do Pará, 2024-10) NEVES, Jorge Kevin da Silva; MELO, Francisco Tiago de Vasconcelos; http://lattes.cnpq.br/8939740618818787; https://orcid.org/0000-0001-8935-2923
Amphibians are good models for studies of parasite diversity due to their wide range of life strategies, standing out as hosts for various groups of nematodes, trematodes, cestodes, monogeneans, and acanthocephalans. The structure of parasitic communities in anurans can be influenced by various biotic or abiotic factors. Despite being extensively studied, the taxa found are rarely identified to the species level. To date, no parasitological studies have been conducted on representatives of Osteocephalus cabrerai, leaving the parasitic fauna of these anurans completely unknown. This study aims to characterize the diversity of parasitic helminths of O. cabrerai from the Beija-Flor Brilho de Fogo Extractive Reserve. This thesis comprises two chapters. The first chapter consists of a published Research Article that presents the first records of parasites for O. cabrerai, analyzing the composition and characteristics of the parasitic community, patterns of parasite distribution, and the correlation between host biotic factors and the characteristics of the community. We predominantly found nematodes with a monoxenous life cycle, high prevalence, and abundant infection. Most specimens represent the first record of parasites for the genus Osteocephalus. Additionally, in our analyses, individuals with greater body mass tended to have higher susceptibility to parasitic helminth infections. The second chapter presents a Short Communication with the first molecular and phylogenetic analyses involving A. pella, concluding that the genus Aplectana is not monophyletic. We provide the first study on the helminth community structure of O. cabrerai and add the first sequence of Aplectana from the Neotropical region. Thus, we enhance the understanding of the diversity and ecology of parasitic helminths in anurans, as well as the phylogenetic relationships of species within the family Cosmocercidae.
Acesso aberto (Open Access)
Impacto dos fatores antropogênicos e ambientais na dinâmica do microbioma e nas interações hospedeiro-patógeno em anfíbios
(Universidade Federal do Pará, 2025-04) MOSER, Camila Fernanda; BECKER, Guilherme; PELOSO, Pedro Luiz Vieira Del; http://lattes.cnpq.br/0963420424755544; https://orcid.org/0000-0003-0127-8293
Amphibians are among the most threatened vertebrates, with 41% of species at risk of extinction due to habitat loss, climate change, invasive species, and emerging diseases. A key factor influencing their health is the skin microbiota, a community of symbiotic microorganisms that contribute to immunity and disease resistance. However, this microbiome is highly sensitive to environmental disturbances, which can alter its composition and reduce its protective functions. One of the major threats to amphibians is chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), a pathogen that disrupts skin integrity and weakens host defenses, leading to high mortality rates. This infection interacts with environmental stressors, including pollution and habitat degradation, increasing amphibian vulnerability. This thesis explores the composition and ecological drivers of amphibian skin microbiota, its interactions with Bd, and the effects of environmental disturbances. The results show that microbiome diversity varies across species, seasons, and environmental conditions. A case study on Bd dynamics across different species and environmental conditions demonstrated that infection prevalence and load were lower in warmer temperatures and in species with non-aquatic habits, suggesting that abiotic factors and host ecology significantly influence Bd susceptibility. Furthermore, seasonal variations in microbiota composition were observed, with microbial diversity generally decreasing in colder months. These seasonal shifts could be linked to changes in amphibian behavior and immune function, highlighting the need for long-term monitoring of microbiota-host-pathogen interactions. In conclusion, this thesis provides novel insights into the complex interactions between amphibian microbiota, environmental changes, and disease dynamics. Understanding how anthropogenic disturbances and seasonal variations shape microbiome diversity is essential for developing effective conservation strategies. Future research should focus on longterm monitoring of amphibian microbiomes, explore the role of larval-stage microbiota in pathogen resistance, and investigate microbiome-based interventions to support amphibian populations facing increasing environmental threats.