Dating phylogenetically basal eudicots using rbcL sequences and multiple fossil reference points

• A molecular dating of the phylogenetically basal eudicots (Ranunculales, Proteales, Sabiales, Buxales and Trochodendrales sensuAngiosperm Phylogeny Group II) has been performed using several fossils as minimum age constraints. All rbcL sequences availablein GenBank were sampled for the taxa in focus. Dating was performed using penalized likelihood, and results were compared withnonparametric rate smoothing. Fourteen eudicot fossils, all with a Cretaceous record, were included in this study for age constraints.Nine of these are assigned to basal eudicots and the remaining five taxa represent core eudicots. Our study shows that the choice ofmethods and fossil constraints has a great impact on the age estimates, and that removing one single fossil change the results in themagnitude of tens of million years. The use of several fossil constraints increase the probability of approaching the true ages. Ourresults suggest a rapid diversification during the late Early Cretaceous, with all the lineages of basal eudicots emerging during thelatest part of the Early Cretaceous. The age of Ranunculales was estimated to 120 my, Proteales to 119 my, Sabiales to 118 my,Buxales to 117 my, and Trochodendrales to 116 my.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biologisk systematik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biological Systematics (hsv//eng)

Nyckelord

Cretaceous

dating

eudicots

fossils

Systematics and phylogenetics

Systematik och fylogeni

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)