Helminth Diversity in Anurans from the State of Piauí, Northeastern Brazil: New Occurrences and Ecological Aspects in a Caatinga-Cerrado ecotonal area.

Ecological studies and inventories regarding parasitic helminths in Piauí remain limited. Thus, this study aimed to describe the helminth communities of anurans in the State of Piauí, Northeastern Brazil, and present an updated list of helminth parasites of anurans for this state. We examined 145 anurans of 20 species. Among them, 48 specimens distributed across 12 host species were parasitized. The helminth communities included 12 nematodes and one cestode. We found 20 dominant taxa in the communities, four codominant, and five unsuccessful species. Most helminth parasites exhibited aggregated distribution patterns, and some taxa were found parasitizing more than one host species. In our literature review, we found 32 taxa from three groups (Nematoda, Platyhelminthes, and Acanthocephala) in 21 anuran host species. We report 20 new records of helminth infections in several anuran hosts that have previously been studied in the helminth communities in the State of Piauí, Brazil. In addition, we report the first time in three previously unexamined host species in the region, and present for the first record of Cylindrotaenia americana in Physalaemus cuvieri. These results provide new data on helminth diversity in Piauí and contribute to a better understanding of local patterns of parasite biodiversity.