Species relationships and divergence times in beeches: new insights from the inclusion of 53 young and old fossils in a birth-death clock model.
The fossilized birth-death (FBD) model can make use of information contained in multiple fossils representing the same clade, and we here apply this model to infer divergence times in beeches (genus Fagus), using 53 fossils and nuclear sequences for all nine species. We also apply FBD dating to the fern clade Osmundaceae, with about 12 living species and 36 fossils. Fagus nuclear sequences cannot be aligned with those of other Fagaceae, and we therefore use Bayes factors to choose among alternative root positions. The crown group of Fagus is dated to 53 (62-43) Ma; divergence of the sole American species to 44 (51-39) Ma and divergence between Central European F. sylvatica and Eastern Mediterranean F. orientalis to 8.7 (20-1.8) Ma, unexpectedly old. The FBD model can accommodate fossils as sampled ancestors or as extinct or unobserved lineages; however, this makes its raw output, which shows all fossils on short or long branches, problematic to interpret. We use hand-drawn depictions and a bipartition network to illustrate the uncertain placements of fossils. Inferred speciation and extinction rates imply approximately 5× higher evolutionary turnover in Fagus than in Osmundaceae, fitting a hypothesized low turnover in plants adapted to low-nutrient conditions.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.
Systematic Botany and Mycology, University of Munich, Menzinger Street 67, 80638 Munich, Germany renner@lmu.de.
S S
0000-0003-3704-0703
SS
Renner
Department of Palaeontology, University of Vienna, Althanstraße 14, 1090 Vienna, Austria.
Guido W
0000-0003-0674-3553
GW
Grimm
The Exelixis Lab, Scientific Computing Group, Heidelberg Institute for Theoretical Studies, 68159 Heidelberg, Germany.
Paschalia
P
Kapli
Department of Palaeobiology, Swedish Museum of Natural History, Svante Arrhenius Väg 9, 10405 Stockholm, Sweden.
Thomas
T
Denk
D005075:Biological Evolution; D019143:Evolution, Molecular; D029964:Fagus / Q000502:physiology*; D029624:Ferns / Q000502:physiology*; D005580:Fossils / Q000033:anatomy & histology*; D049810:Genetic Speciation; D008954:Models, Biological; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA
D010940:Plant Proteins
Osmundaceae; beeches; evolutionary turnover rate; fossil record; fossilized birth–death model; molecular-clock calibration