Climbing Higher: Exploring Northern Andean Origin and Non-Floral Trait Evolution in a Rapid, Recent Angiosperm Radiation

Abstract

Aim

The centropogonid clade comprising Burmeistera H.Karst. & Triana, Centropogon C.Presl and Siphocampylus Pohl stands out as one of the most rapid plant radiations in the Neotropics. We investigated the origin and diversification of Burmeistera to enhance our understanding of fruit evolution and other non-floral traits in the genus. By exploring the interplay of morphological, ecological and geographical factors, we sought to provide new insights into how these elements have influenced the evolutionary trajectory of Burmeistera.

Location

Neotropics.

Time Period

Late Pliocene to present.

Taxon

Burmeistera H.Karst. & Triana (Lobelioideae: Campanulaceae).

Methods

Using Hyb-Seq data from 329 nuclear loci, we reconstructed a phylogenetic tree of Burmeistera using maximum likelihood in RAxML and calibrated the final tree with prior age estimates for the Lobelioideae. Additionally, we estimated the species tree in ASTRAL and performed various phylogenetic comparative analyses to explore the historical biogeography and evolution of non-floral traits across Burmeistera.

Results

Burmeistera originated in the Western Cordillera of the Colombian Andes, with species dispersing to the rest of the Northern Andes and Central America between the Late Pliocene and Mid-Pleistocene. Inflated fruits have evolved multiple times in the genus, with their distribution varying by region but reaching the highest proportion in the eastern slopes of the Andes. Higher elevations and larger fruit sizes both increased diversification, especially in a late-branching clade characterised by inflated berries and a climbing habit, which underscores the role of these traits in driving diversification.

Main Conclusions

Studies of diverse but overlooked taxa, such as Burmeistera, can greatly aid our understanding of the ecology and evolution of Neotropical cloud forest ecosystems.