Hifomicetos associados à serrapilheira nas áreas de várzeas do município de Cachoeira do Arari, Ilha de Marajó, Pará, Brasil.

Abstract

Amazonian floodplains (várzeas) are dynamic ecosystems characterized by periodic flooding and marked seasonal variations between flood and ebb periods. Although several studies on the fauna and flora of these environments have been carried out, data on fungal diversity are still scarce. Hyphomycetes stand out among the fungi present in várzeas. They represent the asexual phase of the Ascomycota and Basidiomycota phyla and play a fundamental ecological role, colonizing submerged plant substrates and contributing to nutrient cycle and energy flow in aquatic ecosystems. In order to expand the knowledge about this group, an inventory of hyphomycetes was carried out in várzeas of Marajó Island, Pará, Brazil. Four expeditions were carried out in floodplain areas of the municipality of Cachoeira do Arari, located on the east coast of the island, between January and September 2024. The collected samples were subjected to washing techniques under running water and kept in a moist chamber for up to 45 days. The reproductive structures of the fungi were observed under a stereomicroscope and mounted on semi-permanent slides for morphological analysis and identification. In total, 228 taxa distributed in 121 genera, 52 families, 36 orders and five classes were identified; 106 taxa were identified to the species level. Most fungi occurred in branches (112), followed by leaves (84); 32 occurred in both of these substrates. The results showed a high diversity of hyphomycetes acting as decomposers of submerged litter in várzeas of Marajó Island. Ecological analyses showed that species turnover is the main component of beta diversity, indicating the high replacement of species across substrates, localities and periods. This study presents the record of a new hyphomycete for the state of Pará (Chaetopsina fulva), seven new records for the Amazon (Arthrotaeniolella aquatica, Beltraniella havanensis, Circinotrichum falcatisporum, Eversia parvula, Magnopulchromyces scorpiophorus, Paliphora bilorata and Zanclospora bonfinensis), three for South America (Helicorhoidion pulchrum, Spadicoides cubensis and Xylocladium clautriavii) and two for the American continent (Sporidesmiella incrassata and Trichocladium aquaticum). Furthermore, a new species, Deightoniella sp. nov. is described. This work significantly expands the knowledge about fungi in Amazonian aquatic environments and highlights the importance of studies in Amazonian várzeas to explore the fungal biodiversity of the region.