Aiouea altomacaensis (Lauraceae), new species from the mountains of Rio de Janeiro, Brazil

The Brazilian Atlantic Rainforest is one of the centres of diversity for the genus Aiouea (Lauraceae). This Neotropical genus comprises approximately 85 species, 35 of which occur in Brazil, with 24 being endemic. Based on a taxonomic review of herbarium collections and recently gathered specimens, we propose a new species of Aiouea endemic to the country and the Atlantic Rainforest. Herein, we describe and illustrate Aiouea altomacaensis . It is a medium-sized tree endemic to the State of Rio de Janeiro, southeast Brazil, specifically restricted to the mountainous region between Nova Friburgo and Petrópolis. This taxon can be confused with three others: Aiouea acarodomatifera , A. albopunctata and A. ombrophila . Aiouea altomacaensis differs from these mainly by its narrow leaves and short inflorescences. Initially, the species was assessed as Endangered (EN) under IUCN Criteria due to its restricted distribution. However, Data Deficient (DD) is a more appropriate classification until more reliable information on its actual range becomes available.