Phylogenetic relationships of the species of Abuta in Peru with emphasis in the affinities of Abuta grandifolia s.l. (Menispermaceae)

Abuta (Anomospermeae, Menispermaceae), comprising 32 species, is the second most diverse genus of Neotropical moonseeds. Several species are known as sources of the arrow poison curare and are used in traditional medicine; among them, Abuta grandifolia is the best known for the treatment of various ailments. This species exhibits marked morphological variation, which previous studies have arranged into four informally recognized morphological groups (Agstsl, Agvar, Agll, and Aggu). Despite its widespread use, the phylogenetic relationships of A. grandifolia within Abuta remain poorly understood. A recent family-wide molecular study recovered A. grandifolia as sister to the remaining species of the genus, although taxon sampling was limited. In this study, we expand taxon sampling within Abuta to investigate species-level phylogenetic relationships, with focus on the affinities of A. grandifolia. Phylogenetic analyses based on combined ITS and two plastid DNA regions support the monophyly of Abuta and provide new insights into interspecific relationships. Accessions representing individual species, including the widespread A. grandifolia, were recovered as monophyletic. Within A. grandifolia, accessions form four well-supported clades that are congruent with the previously recognized morphological groups. Pending resolution of taxonomic limits and associated nomenclature, the species is treated here in a broad sense and referred to as A. grandifolia s.l. Notably, Abuta mycetandra, a poorly known taxon, was recovered as the sister lineage to A. grandifolia s.l.