RESUMO

The phylum Arthropoda comprises approximately 85% of all described animal species. The class Arachnida includes some invertebrates of great importance as they are either involved in the transmission of diseases or poses a risk of human envenomation. Spiders belonging to the genus Phoneutria sp., are the arachnids exhibiting medical importance. These animals were quarantined and maintained in captivity at the Biotério de Artrópodes of the Instituto Butantan, São Paulo, Brazil, for the production of the anti-arachnid serum. A total 509 feces samples from different Phoneutria nigriventer were analyzed, and 131 (25.73%) samples were found to be positive for flagellates and ciliates. All positive samples were subjected to DNA extraction and amplification of 18S gene. A total of 16 sequences were obtained and analyzed using BLAST. Sequences were identified as Colpoda steiini, one as Colpoda aspera, one to Colpoda sp., and one as "ciliated". Four identified as Parabodo caudatus, two as Urostipulosphaera sp., one as Helkesimastix sp., and one as a Euglena-like. The presence of clinical signs was observed in 16 spiders. The intestinal protozoa that affect armed spiders were identified for the first time as an initial step for understanding the parasitic diseases in these organisms.