Five new species of Lithospermum L. (Boraginaceae tribe Lithospermeae) in Andean South America: Another radiation in the Amotape-Huancabamba Zone.

We present a revision of Lithospermum for South America based on extensive field work and herbarium study which leads to the recognition often species including five new to science: Lithospermum bolivariensis, L. cuzcoensis, L. leymebambensis and L. rodriguezii from Peru, and L. azuayensis from Ecuador. The South American species group is morphologically heterogeneous and includes a wide range of growth forms, pollen types and corolla shapes. Molecular data indicate that the species from Ecuador, Peru and Bolivia are monophyletic (South American species group) and represent the sister group of Mexican L. distichum. Lithospermum mediale, disjunct between Colombia/Venezuela and Guatemala/Mexico, represents an independent introduction to South America. Diversification of Andean Lithospermum appears to have progressed from South to North, with the basal taxa being present in the high Andes of southern Peru. The bulk of the species is concentrated in the Arnotape-Huancabamba Zone (northern Peru to southern Ecuador), with five neo-endemic species being restricted to this area. Lithospermum apparently arrived in the Central Andes Ca. 5 Ma and subsequently migrated and diversified northwards, possibly parallel to the uplift of the northern Andes. [ABSTRACT FROM AUTHOR]