Reconstruction of the evolutionary biogeography reveals the origins of Alpinia Roxb. (Zingiberaceae): A case of “out-of-Asia” migration to the Southern Hemisphere

ABSTRACT Alpinia is considered the largest genus of Zingiberaceae with ca. 250 species occurring in tropical and subtropical Asia, Australia, and Pacific Islands. The historical biogeography of Alpinia was conducted to explain where Alpinia originated and how it migrated to other regions. The phylogeny, divergence times and ancestral area reconstruction of Alpinia were performed by using the molecular data based on the comprehensive taxon sampling. Our results provide an objective approach to understand the historical biogeography of Alpinia. The genus originated in Asia during the Late Cretaceous ca. 69 Ma and started to diverge after the K-Pg boundary during the early Paleocene with the presence and development of the tropical rainforest and a warm, moist climate. Alpinia migrated to Malesia and then dispersed to Australasia. The molecular analyses supported the diversification of Alpinia in Asia and Malesia. Additionally, the Indian Alpinia has likely a common ancestor with Renealmia and Aframomum, and it is possible that after originating in Asia, Alpinia migrated from Asia to India then to Africa during the early period of collision between the Indian subcontinent and Eurasia to form the common ancestor of Indian Alpinia, Renealmia, and Aframomum. Our phylogeny provides a framework for studies in biogeography, comparative ecology, and evolution.