Morpho-anatomical novelties of a dwarf Syagrus (Arecaceae) of canga: implications for ecology, conservation, and taxonomy

Canga are ferruginous campos rupestres with edapho-climatic harshness and high levels of biodiversity and endemism. They are also subjected to constant anthropic threats. The isolated Serra do Cabral mountain in the Brazilian state of Minas Gerais is home to a micro-endemic Syagrus of canga—Syagrus graminifolia subsp. cabraliensis. The type locality was impacted by past mining activities and currently experiences intensive fires and is crossed by a road with daily traffic. The taxon stands out with features not yet recorded within Syagrus, such as the presence of osmophores and three to six endocarp pores (subbasal or subbasal and subapical). It also has some flowers in tetrads, which is a rare feature within the genus. The well-developed prostrate stem may increase the ability of the taxon to survive intense fires. However, numerous seeds fall prey to beetle larvae, which helps to explain the absence of other populations in nearby areas. Geographic isolation combined with morpho-anatomical novelties clearly differentiate the taxon from S. graminifolia, and supports a new taxonomic status and combination, here proposed as the species Syagrus cabraliensis. The restricted range of occurrence of the only known canga species and the imminent risk of extinction caused by anthropogenic habitat destruction makes including the area of the population of S. cabraliensis within the borders of Serra do Cabral State Park, and diverting the road that crosses it, urgent necessities. The proposed status of species will increase visibility and contribute to underpinning the importance of canga as hotspots for conservation policies.