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Patterns of speciation are similar across mountainous and lowland regions for a Neotropical plant radiation (Costaceae: Costus )
Author(s) -
Vargas Oscar M.,
Goldston Brittany,
Grossenbacher Dena L.,
Kay Kathleen M.
Publication year - 2020
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.14108
Subject(s) - species richness , ecology , biology , genetic algorithm , endemism , biogeography , biodiversity , parapatric speciation , range (aeronautics) , pollination , pollen , gene flow , genetic variation , biochemistry , materials science , composite material , gene
Abstract High species richness and endemism in tropical mountains are recognized as major contributors to the latitudinal diversity gradient. The processes underlying mountain speciation, however, are largely untested. The prevalence of steep ecogeographic gradients and the geographic isolation of populations by topographic features are predicted to promote speciation in mountains. We evaluate these processes in a species‐rich Neotropical genus of understory herbs that range from the lowlands to montane forests and have higher species richness in topographically complex regions. We ask whether climatic niche divergence, geographic isolation, and pollination shifts differ between mountain‐influenced and lowland Amazonian sister pairs inferred from a 756‐gene phylogeny. Neotropical Costus ancestors diverged in Central America during a period of mountain formation in the last 3 million years with later colonization of Amazonia. Although climatic divergence, geographic isolation, and pollination shifts are prevalent in general, these factors do not differ between mountain‐influenced and Amazonian sister pairs. Despite higher climatic niche and species diversity in the mountains, speciation modes in Costus appear similar across regions. Thus, greater species richness in tropical mountains may reflect differences in colonization history, diversification rates, or the prevalence of rapidly evolving plant life forms, rather than differences in speciation mode.