MOLECULAR AND MORPHOMETRIC APPROACHES IN RECENTLY RADIATED SPECIES: Inga subnuda SALZM. EX BENTH AND Inga vera WILLD. (LEGUMINOSAE, MIMOSOID CLADE)

The species-rich genus Inga (Leguminosae) presents ca. 300 species widespread throughout the Neotropics and is recognized by its recent and rapid diversification. Forty-eight species of Inga are endemic of the Brazilian Atlantic Forest. Among them, Inga subnuda, with two subspecies: subsp. subnuda, which occurs from the state of Paraiba to Rio de Janeiro; and subsp. luschnathiana, which occurs from Espirito Santo to the state of Santa Catarina. Both subspecies occur in sympatry in the southeastern region and share floral and leaf characters, which hampers the morphological delimitation. The co-occurrence of Inga vera subsp. affinis. with both I. subnuda subspecies results in intermediate morphologies between I. vera subsp. affinis and I. subnuda subsp. luschnathiana, making the distinction between the latter species even harder. We sampled 94 individuals from 8 natural populations and evaluated morphological characters previously described as distinctive among the subspecies of I. subnuda in addition to others not measured yet. We used 84 plastid (trnD-trnT spacer) and 58 nuclear (ITS 1 and 2) sequences to characterize the phylogenetic relationships between the taxa. The results obtained point out I. subnuda subsp. subnuda as a more structured taxon in relation to the other subspecies, whilst I. subnuda subsp. luschnathiana and I. vera subsp. affinis constituted a cohesive group. The apportionment of haplotypes differed between the markers used, thus evincing a retention of ancestral polymorphism between the subspecies, given their recent diversification. This paper explores different lines of evidence, thus contributing to the delimitation of these species. Demographic and biogeographic scenarios are also discussed. A new status of for the taxon currently circumscribed as Inga subnuda subsp. luschnathiana is suggested.