Biogeography of the grasses (Poaceae): a phylogenetic approach to reveal evolutionary history in geographical space and geological time

Abstract

The grasses (Poaceae) are the fifth most diverse family of angiosperms, including 800 genera and more than 10 000 species. Few phylogenetic studies have tried to investigate palaeo‐biogeographical and palaeo‐ecological scenarios that may have led to present‐day distribution and diversity of grasses at the family level. We produced a dated phylogenetic tree based on combined plastid DNA sequences and a comprehensive sample of Poaceae. Furthermore, we produced an additional tree using a supermatrix of morphological and molecular data that included all 800 grass genera so that ancestral biogeography and ecological habitats could be inferred. We used a likelihood‐based method, which allows the estimation of ancestral polymorphism in both biogeographical and ecological analyses for large data sets. The origin of Poaceae was retrieved as African and shade adapted. The crown node of the BEP + PACCMAD clade was dated at 57 Mya, in the early Eocene. Grasses dispersed to all continents by approximately 60 million years after their Gondwanan origin in the late Cretaceous. PACCMAD taxa adapted to open habitats as early as the late Eocene, a date consistent with recent phytolith fossil data for North America. C4 photosynthesis first originated in Africa, at least for Chloridoideae in the Eocene at c. 30 Mya. The BEP clade members adapted to open habitats later than PACCMAD members; this was inferred to occur in Eurasia in the Oligocene. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162, 543–557.

Late Cretaceous origin of the rice tribe provides evidence for early diversification in Poaceae

“…This placement of the Late Cretaceous fossils has radical implications for the amount of diversification that had taken place within the Poaceae at the close of the Mesozoic era. In the phylogeny used herein, it can be inferred that, by 65 Ma (K-Pg boundary), the Ehrhartoideae had split from the Pooideae + PACMAD lineage 18 , or else from the other clades within the BEP 13,16,17 . In addition, the Oryzeae must have split from the Ehrharteae within the Ehrhartoideae.…”

Available Climate Regimes Drive Niche Diversification during Range Expansion

“…Trees were generated using Bayesian and relaxed-clock methods in BEAST, version 1.5.2 (Drummond and Rambaut 2007), and calibrated using a secondary calibration point obtained from Bouchenak-Khelladi et al (2010). Details of the tree generation and molecular dating methods are described in Antonelli et al (2011;see also Humphreys et al 2011).…”

“…Furthermore, the repeated, spatially distinct radiations within the clade (Linder et al 2014) should warrant statistical power in analyses of niche evolution. The Danthonioideae likely originated in southern Africa in the Oligocene (21-38 Ma; Bouchenak-Khelladi et al 2010), and multiple early dispersals to Australia, New Zealand, and South America and subsequent dispersals during the Late Miocene and Pliocene to Southeast Asia, Northern America, and Europe resulted in the clade now occupying all continents except Antarctica and Greenland ).…”

Widespread Development of Silcrete in the Cretaceous and Evolution of the Poaceae Family of Grass Plants

“…Leaves of modern day wild grass (which also belongs to the Poaceae family of grass) were collected, dried, carbon coated and and examined using an ISI ABT-55 scanning electron microscope (SEM) with Link Analytical 10/55S EDAX facility for the occurrence of silica in the leaves. This is based on the assertion that the Poaceae family of grass plants evolved and diversified during the Cretaceous as it is documented in the biogeological records (e.g., Bouchenak-Khelladi et al, 2010;Bremer 2002;Jassen and Bremer 2004;Kellogg, 2010). X-ray spectra and backscattered images were obtained from the SEM.…”

“…The grass family includes about 10,000 species classified into 600-700 genera (Clayton and Renvoize, 1986;Watson and Dallwitz, 1989). The evolutionary history of grass is complex, however biogeographic studies (e.g., Bouchenak-Khelladi et al, 2010;Bremer 2002;Jassen and Bremer 2004;Kellogg, 2001) have shown that the Poaceae family evolved and diversified during the Cretaceous period. This is consistent with the works of Prasad et al (2005) who reported the occurrence of silicified plant tissues (phytoliths) preserved in the Cretaceous Lameta Formation occurring at Pisdura, central India.…”