Expanding the occurrence of Parmotrema enteroxanthum (Parmeliaceae, lichenized Ascomycota) in South America: first record from Brazil, and notes on distribution and conservation assessment

Parmotrema enteroxanthum is a restricted distribution foliose lichen, easily recognized by its yellow medulla and salazinic acid content. Previously known only from Venezuela, Colombia, and Bolivia, its distribution in South America remains poorly understood. This study documents the first record of the species in Brazil, with notes on ecology and conservation. Field collections were conducted from Cerrado areas in the state of Maranhão, northeastern Brazil. Morphological and chemical analyses were performed using microscopy, spot tests, and thin-layer chromatography. Distribution data were compiled from GBIF, and conservation status was preliminarily assessed using GeoCat, based on IUCN criteria. Parmotrema enteroxanthum was recorded in cerradão vegetation, extending its range into Brazil and the Cerrado domain (Brazilian Savanna). The species occurs in seasonally dry and rainforest habitats (open/ exposed microhabitats) in South America. Geospatial analysis indicated a wide Extent of Occurrence (~3.6 million km2), but a very restricted Area of Occupancy (16 km2), suggesting a fragmented distribution. According to IUCN criteria, the species may be considered potentially Endangered (EN) due to its low number of localities and ongoing habitat loss. This finding underscores the Cerrado as both a center of lichen diversity and a highly threatened biome.