Phylogeny of the Turneraceae clade (Passifloraceae s.l.): Trans–Atlantic disjunctions and two new genera in Africa

Abstract

AbstractTurneraceae, with just over 200 species in 10 genera, is today often included in a widely circumscribed Passifloraceae. The vast majority of the species are found in the New World, whereas generic diversity is largest in the Old World. According to current circumscriptions, three of the genera show trans–Atlantic disjunctions: Turnera with over 135 species in America and two species in Africa (one in the south–western and one in the north–eastern part), Piriqueta with 44 species in America and one in southern Africa, and Erblichia with one species in Central America and four in Madagascar. The phylogeny of Turneraceae is reconstructed based on DNA sequences from plastid trnL–F and nuclear ITS and sampling for all genera, including both New and Old World species for the trans–Atlantic groups to test their monophyly. The genera of Turneraceae form a strongly supported monophyletic group, the Turneraceae clade, within Passifloraceae s.l. The phylogeny is geographically structured, with one clade comprising American species only, except for the two African species of Turnera, and another clade with all other African species plus the Central American Erblichia odorata. Turnera is retrieved as monophyletic with the two African species appearing as close relatives of T. ulmifolia, the type of Turnera. The existence of a trans–Atlantic disjunction in Turnera is therefore supported. It is most likely caused by long–distance dispersal and estimated to be not older than late Miocene. In Piriqueta only the American species are supported as a monophyletic group, whereas the single African species is resolved as a member of the African clade. The trans–Atlantic disjunction in Piriqueta is therefore not supported and the African species is proposed to be placed in a genus of its own, Afroqueta gen. nov., as Afroqueta capensis comb. nov. Erblichia on Madagascar is supported as sister to Mathurina, a genus endemic to Rodrigues Island in the Mascarenes, and does not group with E. odorata in Central America, the type of Erblichia. The trans–Atlantic disjunction in Erblichia is therefore not supported either and the genus Arboa gen. nov. is proposed to accommodate the four Malagasy species, Arboa integrifolia comb. nov., Arboa berneriana comb. nov., Arboa madagascariensis comb. nov., and Arboa antsingyae comb. nov.