Rapid diversification of Tragopogon and ecological associates in Eurasia
Open Access
- 16 November 2012
- journal article
- Published by Oxford University Press (OUP) in Journal of Evolutionary Biology
- Vol. 25 (12), 2470-2480
- https://doi.org/10.1111/j.1420-9101.2012.02616.x
Abstract
Tragopogon comprises approximately 150 described species distributed throughout Eurasia from Ireland and the UK to India and China with a few species in North Africa. Most of the species diversity is found in Eastern Europe to Western Asia. Previous phylogenetic analyses identified several major clades, generally corresponding to recognized taxonomic sections, although relationships both among these clades and among species within clades remain largely unresolved. These patterns are consistent with rapid diversification following the origin of Tragopogon, and this study addresses the timing and rate of diversification in Tragopogon. Using BEAST to simultaneously estimate a phylogeny and divergence times, we estimate the age of a major split and subsequent rapid divergence within Tragopogon to be ~2.6 Ma (and 1.7-5.4 Ma using various clock estimates). Based on the age estimates obtained with BEAST (HPD 1.7-5.4 Ma) for the origin of crown group Tragopogon and 200 estimated species (to accommodate a large number of cryptic species), the diversification rate of Tragopogon is approximately 0.84-2.71 species/Myr for the crown group, assuming low levels of extinction. This estimate is comparable in rate to a rapid Eurasian radiation in Dianthus (0.66-3.89 species/Myr), which occurs in the same or similar habitats. Using available data, we show that subclades of various plant taxa that occur in the same semi-arid habitats of Eurasia also represent rapid radiations occurring during roughly the same window of time (1.7-5.4 Ma), suggesting similar causal events. However, not all species-rich plant genera from the same habitats diverged at the same time, or at the same tempo. Radiations of several other clades in this same habitat (e.g. Campanula, Knautia, Scabiosa) occurred at earlier dates (45-4.28 Ma). Existing phylogenetic data and diversification estimates therefore indicate that, although some elements of these semi-arid communities radiated during the Plio-Pleistocene period, other clades sharing the same habitat appear to have diversified earlier.Keywords
This publication has 67 references indexed in Scilit:
- Extended phylogeny of Aquilegia: the biogeographical and ecological patterns of two simultaneous but contrasting radiationsÖsterreichische botanische Zeitschrift, 2009
- Historical biogeography of the endemic Campanulaceae of CreteJournal of Biogeography, 2009
- Chromosome Numbers in Veroniceae (Plantaginaceae): Review and Several New Counts1Annals of the Missouri Botanical Garden, 2008
- Influence of Mediterranean sea‐level changes on the Dacic Basin (Eastern Paratethys) during the late Neogene: the Mediterranean Lago Mare facies decipheredBasin Research, 2005
- Phylogeny and biogeography of Valerianaceae (Dipsacales) with special reference to the South American valeriansOrganisms Diversity & Evolution, 2005
- Veronica: Parallel morphological evolution and phylogeography in the MediterraneanÖsterreichische botanische Zeitschrift, 2004
- Syntaxonomy of theTrifolio-Geranietea (saum vegetation) in SloveniaFolia Geobotanica et Phytotaxonomica, 1997
- Alternate interpretation of the Messinian salinity crisis: Controversy resolved?Geology, 1996
- Developing model systems for molecular biogeography: Vicariance and interchange in marine invertebratesExperientia Supplementum, 1994
- Vegetation Response to Upper Pliocene Glacial/Interglacial Cyclicity in the Central MediterraneanQuaternary Research, 1993