Evolutionary dynamics and biogeography of Musaceae reveal a correlation between the diversification of the banana family and the geological and climatic history of Southeast Asia.

Brecht Verstraete,Steven B. Janssens,Filip Vandelook,Erik Smets,Rony Swennen,Edmond De Langhe,Ines Vandenhouwe

doi:10.1111/nph.13856

Abstract

Summary Tropical Southeast Asia, which harbors most of the Musaceae biodiversity, is one of the most species‐rich regions in the world. Its high degree of endemism is shaped by the region's tectonic and climatic history, with large differences between northern Indo‐Burma and the Malayan Archipelago. Here, we aim to find a link between the diversification and biogeography of Musaceae and geological history of the Southeast Asian subcontinent.The Musaceae family (including five Ensete, 45 Musa and one Musella species) was dated using a large phylogenetic framework encompassing 163 species from all Zingiberales families. Evolutionary patterns within Musaceae were inferred using ancestral area reconstruction and diversification rate analyses.All three Musaceae genera – Ensete, Musa and Musella – originated in northern Indo‐Burma during the early Eocene. Musa species dispersed from ‘northwest to southeast’ into Southeast Asia with only few back‐dispersals towards northern Indo‐Burma.Musaceae colonization events of the Malayan Archipelago subcontinent are clearly linked to the geological and climatic history of the region. Musa species were only able to colonize the region east of Wallace's line after the availability of emergent land from the late Miocene onwards.

Highlights

Tropical Southeast Asia can be considered as one of the most biodiversity-rich regions in the world
In order to correctly estimate node ages for Ensete, Musa and Musella, we extended the Musaceae dataset with 156 Zingiberales species and two outgroup taxa (Methods S1)
Within the lineage towards the Musa and Rhodochlamys sections, the positions of the M. acuminata ssp. schizocarpa clade, M. balbisiana clade and M. acuminata ssp. siamea differ between the two phylogenetic trees, yet these incongruences are only weakly supported (Fig. S2)

Summary

Introduction

Tropical Southeast Asia can be considered as one of the most biodiversity-rich regions in the world. The enormous plant biodiversity in Southeast Asia can be partly ascribed to its current geographic position in tropical and subtropical climatic zones, it is especially the region’s complex tectonic and climatic evolution that has shaped the present species richness and high degree of endemism (Sodhi et al, 2004; Woodruff, 2010; Wong, 2011). When geographically and climatically comparing mainland Indo-Burma – with its northern boundary situated in the tropical area of Yunnan (Southwest China) – with the islands of Sunda and Sahul, it is clear that their evolutionary history is remarkably different, despite being part of the same large Southeast Asian geographic region (de Bruyn et al, 2014; Deng et al, 2014). The northern area of tropical Southeast Asia (further referred to as northern Indo-Burma), despite its high latitude and elevation, has a tropical moist climate.

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Conclusion