Species Delimitation of Endemic Atlantic Forest Inga subnuda (Leguminosae, Caesalpinioideae, mimosoid clade) Subspecies Based on Morphological, Ecological and Palaeoecological Data

Inga subnuda Salzm. ex Benth. are one of 31 endemic species in the Brazilian Atlantic Forest. Intermixed leaf and floral traits have made morphological distinctiveness difficult, and its current taxonomic treatment considers I. subnuda as one species with two subspecies. We aim to explore different lines of evidence to disentangle and clarify species boundaries in these two subspecies. Morphological variation and bioclimatic data of the two subspecies of the complex were assessed by using multivariate morphometric analyses and ecological niche modeling. Morphological quantitative characters allowed the recognition of different groups. The climatic space was similar but not identical, and the recent climatic cycles that could have shaped the current distribution are discussed. The results of our integrative study suggest regard both subspecies as two different species. Moreover, we propose a change in status of I. subnuda subsp. luschnathiana to the rank of species. The new up-ranked taxon is described and illustrated.