Evolution and Diversification in the Sapindales
Muellner, Alexandra N. , Vassiliades, Dionyssios D. , Renner, Susanne S. .
Biebersteiniaceae: relationships, geographic origin, and revised crown group age estimates for the sapindalean families.
Biebersteiniaceae comprise a single genus with four species of perennial herbs occurring in temperate mountainous regions from central Asia to Greece. A previous molecular phylogenetic study placed one of the species in an isolated position in Sapindales, while morphological studies traditionally placed Biebersteinia in or near Geraniaceae, albeit doubtfully. We tested the monophyly and placement of the family with data from the chloroplast genes rbcL and atpB obtained for all four species and representatives of all families of Sapindales plus relevant outgroups for a total of up to 114 taxa. Parsimony, Bayesian, and likelihood trees agree in placing Biebersteinia in the Sapindales, possibly as sister to the other eight families. Strict and relaxed molecular clocks constrained with fossils of Biebersteinia and up to eight other Sapindales suggest that the crown group of Biebersteinia diversified in the Oligocene and Miocene, while the stem lineage dates back to the Late Paleocene, if not the Early Paleocene, thus predating the collision of India with southern Asia and the uplift of large mountain chains and plateaus. Ages for other sapindalean families are earlier than those obtained in more sparsely sampled analyses, although estimates for Burseraceae agree surprisingly well. Ancestral area analyses suggest that Biebersteinia expanded from the eastern part of its distributional range (mainly the mountainous regions of Tibet and Inner Mongolia) to the west. Our results highlight the need for dense taxon sampling as well as the importance of checking results against other types of evidence if time estimates are to be trusted. Sapindales, with their rich fossil record, provide an exceptional system for comparing different clock approaches because they permit such critical cross-validation.
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1 - Research Institute Senckenberg, Department of Botany and Molecular Evolution, Grunelius-Moellgaard Laboratory, Senckenberganlage 25, Frankfurt, D-60325, Germany
2 - 24 Issiodou St, Athens, GR-10674, Greece
3 - Ludwig-Maximilians Universitaet Muenchen, Faculty of Biology, Munich, D-80638
Bayesian relaxed clock
Presentation Type: Symposium or Colloquium Presentation
Location: Boulevard B/Hilton
Date: Tuesday, July 10th, 2007
Time: 8:30 AM