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

Abstract

Abstract— Inga subnuda is one of 31 Inga species endemic to the Brazilian Atlantic Forest and is currently treated as having two subspecies (I. subnuda subsp. subnuda and I. subnuda subsp. luschnathiana). However, due to intermixed leaf and floral traits, these subspecies are difficult to morphologically distinguish. This study aimed to better understand the boundaries of these two subspecies and to test if these taxa should be treated at the species level. Morphological variation and bioclimatic data related to the two subspecies of the complex were assessed using multivariate morphometric analyses and ecological niche modeling. Different groups were recognized using morphological quantitative characters. The climatic space was similar but not identical, and recent climatic cycles that could have shaped the current distributions of the subspecies are discussed. The results of our integrative study suggest the subspecies are distinct species. Thus, we propose changing the status of I. subnuda subsp. luschnathiana to the rank of species. The new taxon is described and illustrated.