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Abstract Detail



Biogeography

Berger, Brent [1], Kriebel, Ricardo [2], Spalink, Daniel [2], Sytsma, Kenneth J. [2].

Divergence times, historical biogeography, and shifts in speciation rates of Myrtales.

We examine the eudicot order Myrtales, a clade that has strong Gondwanan representation for most of its families. Although previous phylogenetic studies greatly improved our understanding of intergeneric and interspecific relationships within the order, our understanding of inter-familial relationships still remains unresolved and thus we also lack a strong time-calibrated chronogram to address hypotheses (e.g., biogeography and diversification rates) that have implicit time assumptions. Six loci (rbcL, ndhF, matK, matR, 18S, and 26S) were amplified and sequenced for 107 taxa across Myrtales and three outgroup taxa from Geraniales and ten fossil priors were utilized to produce a chronogram in BEAST. Combretaceae is identified as the sister clade to all remaining families with moderate support, and within the latter clade, two strongly supported groups are seen: 1) Onagraceae + Lythraceae form a subclade with strong support, 2) The Melastomataceae + Vochysiaceae and the Myrtaceae + CAP families. Divergence time estimates suggest Myrtales diverged from Geraniales c. 123.5 Mya during the Aptian of the Early Cretaceous. The crown date for Myrtales is estimated at c. 116.4 Mya (Albian-Aptian). BioGeoBEARS showed significant improvement in the likelihood score when the “jump dispersal” parameter was added. South America and/or Africa are implicated as important ancestral areas in most deeper nodes. BAMM diversification analyses indicate that the best configuration included three significant shifts in speciation rates within Myrtales: near the crown of Melastomataceae (c. 67-64 Mya), along the stem of subfamily Myrtoideae (Myrtaceae; c. 75 Mya), and along the stem of tribe Combreteae (Combretaceae; c. 50-45 Mya).


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1 - St. John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA
2 - University of Wisconsin, Department of Botany, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
BAMM diversification
BioGeoBEARS
biogeography
fossil
Myrtales
Gondwana
Cretaceous.

Presentation Type: Oral Paper:Papers for Topics
Session: 59
Location: Salon 3/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 10:15 AM
Number: 59008
Abstract ID:407
Candidate for Awards:None


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