Dating origin orchidaceae 100 dating sites in california


03-Sep-2017 20:18

However, we estimate the crown age of the five orchid subfamilies to be generally (~1-8 Ma) younger than previously calculated under the Penalized Likelihood algorithm and using a single internal fossil calibration.

The crown age of Contrary to recent suggestions that orchid diversification began in a period of global warming, our results place the onset of diversification of the largest orchid subfamilies (Orchidoideae and Epidendroideae) in a period of global cooling subsequent to the Early Eocene Climatic Optimum.

The diversification of appears even more correlated to late Tertiary climatic fluctuations than previously suggested.

With the incorporation of new fossils in the orchid phylogeny and the use of a method that is arguably more adequate given the present data, our results represent the most up-to-date estimate of divergence times in orchids.].

Then, to explore how the high-level age estimates obtained here may affect the evolutionary interpretation of a species-level orchid clade, we date the origin and diversification of the rare South American orchid genus ]. Half of these are "micro-endemic" - known from a single natural population, and some only from the type collection.

This represents the first definitive fossil record for the Orchidaceae.

Reprinted by permission from Macmillan Publishers Ltd: Nature 448(30), copyright 2007.

The genus is endemic to Brazil, where it is confined to the High Altitude Rocky Complexes (Brazilian Campos Rupestres and Campos de Altitude) of Minas Gerais, Rio de Janeiro, Espírito Santos and Bahia states. We have been able to obtain or generate sequences for all but a single species, thus reaching a 98% complete species sampling..

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Support values for the different clades and branches were high, with only a few values below 0.90 Bayesian posterior probability.

The most diverse orchid subfamilies Orchidoideae and Epidendroideae appear to have started to diversify in the Eocene, 50 Ma (95% CI: 34 - 67 Ma) and 44 Ma (95% CI: 29 - 60 Ma), respectively (Table ].