Resolving the evolutionary history of Ctenium and Kampochloa using phylogenomics, and a new circumscription of Cteniinae (Cynodonteae, Poaceae)

Abstract

AbstractCtenium has about 20 species distributed in Africa, Arabia, and the Neotropics, with no species occurring on more than one continent. Its relationship with the morphologically similar Kampochloa is still unclear and has not been investigated. In this study, we performed phylogenomic analyses using 71 protein‐coding genes of 24 newly sequenced plastomes, of 13 species of Ctenium and 1 species of Kampochloa to understand their biogeography and the phylogenetic and evolutionary relationships between these two genera and within Ctenium. Our results support two major clades of Ctenium: the Neotropics and Old‐World clades. Kampochloa is shown to be a close relative of the genus Ctenium, and their morphological similarities support this. Divergence time estimation analyses show that Kampochloa and Ctenium diverged around 7.99 Ma, and might have originated in the late Miocene during the rapid expansion of C4 grasslands. With this evidence from morphology and phylogenomic data, we propose the inclusion of the previously unplaced Kampochloa into the subtribe Cteniinae.