Phylogeny and taxonomy of the Andean Gynoxys group (Asteraceae, Senecioneae, Tussilagininae). Genus concepts and species diversity within the Gynoxyoid clade (Senecioneae, Compositae)

Abstract: The Gynoxyoid is a monophyletic group of five morphologically diverse genera (Aequatorium, Gynoxys, Nordenstamia, Paracalia and Paragynoxys). The delimitation of the genera is meanly based on morphological and distributional data, yet no study focused on the origin and evolution of the morphological diversity of the clade. We inferred the ancestral character-state of eleven morphological characters on the latest comprehensive whole plastid phylogenetic tree which comprises representatives of all genera. Additionally, we evaluated the character-states on all members of the Gynoxyoids and elaborated a taxonomic treatment for all recognized genera in this study. The character-state inferences displayed a high level of homoplasy which difficult genera delimitation. Nevertheless, a specific combination of characters enabled the recognition of four genera: Aequatorium, Gynoxys, Paracalia and Paragynoxys. The genus Nordenstamia was synonymized under Gynoxys including eight species since no molecular nor morphological evidence supported the clade as monophyletic.