A taxonomic revision of the South American papilionoid genus Luetzelburgia (Fabaceae)

Abstract

A taxonomic revision of the monophyletic vataireoid genus Luetzelburgia (Fabaceae, Papilionoideae) is presented, including comments on the biogeography, phylogeny and morphological evolution derived from a combined phylogenetic analysis of morphology and seven DNA regions. The genus is characterized by the unique combination of crimped petals, sericeous on outer surface and biauriculate at the base, oblong to obovate standard petal, lateral and abaxial petals undifferentiated in shape, nearly free filaments and a samara with an indistinct endocarp, usually bearing a small wing on each side of the seed chamber. Luetzelburgia spp. are often confined to disjunct patches of South American seasonally dry tropical forests and woodlands (succulent biome). Our revision involved the examination of about 500 specimens from 56 herbaria. Species circumscription in Luetzelburgia has been a source of confusion because of the difficulty of finding complete herbarium material. All but one species was studied in the field and our extensive field work was critical for arriving at species circumscriptions that relied in large part on floral morphologies. In our revision, four names are lectotypified and one is synonymized, one species is newly described and 13 species are recognized: L.amazonica, L.andina, L.andrade-limae, L.auriculata, L.bahiensis, L.guaissara, L.guianensis, L.harleyi, L.neurocarpa, L.praecox, L.purpurea, L.sotoi and L.trialata. This revision comprises morphological descriptions and illustrations, synonymies, nomenclatural notes, phenology, phylogenetic affinities, distribution maps and preliminary conservation assessments for each species. © 2014 The Linnean Society of London.