<i>Croton buiquensis</i> (Euphorbiaceae), a new species from northeastern Brazil, its phylogenetic placement, and niche modeling

A new species of <i>Croton,</i> microendemic of the dry forests of northeastern Brazil in the state of Pernambuco, is here described. Morphological and ITS molecular data provide evidence for placing <i>C. buiquensis</i> sp. nov. as part of <i>Croton</i> section <i>Pedicellati</i>. Specimens of <i>C. buiquensis</i> had been previously identified in herbaria as <i>C. pedicellatus</i>, but the former can be distinguished from the latter by the hispid indumentum of the leaf blade, the ovate shape of the petals of staminate flowers, pistillate flowers with 4-fid to multifid styles, and a crossbow-shape caruncle. Evidence from ecological niche modeling points to other areas in the state of Pernambuco, specifically the "Agreste" region, as likely locations for the occurrence of the new species, which could be the target of future botanical surveys. <i>Croton buiquensis</i> is here provisionally considered as Critically Endangered based on IUCN criteria. This is the first record of multifid styles (more than six stigmatic tips) in <i>C.</i> sect. <i>Pedicellati</i> and also the first species of the section endemic to the state of Pernambuco.