CONTI, ELENA1*, TORSTEN ERIKSSON2, JUERG SCHOENENBERGER1, KENNETH J. SYTSMA3, and DAVID A. BAUM3. 1Institute of Systematic Botany, University of Zurich, Zollikerstr. 107, CH-8008 Zurich, Switzerland; 2Bergius Foundation, Royal Swedish Academy of Sciences, Box 50017, SE-104 05 Stockholm, Sweden; 3Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA.. - Molecular evidence for Early Tertiary out-of-India dispersal in Crypteroniaceae (Myrtales).
During its journey from Gondwana to Asia, India experienced dramatic
latitudinal and climatic changes that caused massive extinctions in
its biota. However, biogeographical and paleontological studies
suggested that some ancient Gondwanan taxa survived these vicissitudes
and dispersed "out-of-India" into South Asia, after India
collided with the Asian continent in the Early Tertiary. To
corroborate or refute these suggestions, independent estimates for the
time of origin of such groups are needed. Here we present molecular
evidence in support of the "out-of-India" hypothesis for
Crypteroniaceae. Maximum parsimony and likelihood analyses of
rbcL sequences suggested that Crypteroniaceae should be
restricted to Crypteronia, Axinandra, and
Dactylocladus and that Crypteroniaceae, so defined, are sister
to a clade formed by three small S African taxa (Oliniaceae,
Penaeaceae, and Rhynchocalycaeae) and the monotypic S American
Alzateaceae. Three molecular dating approaches (maximum likelihood
under a molecular clock, Langley-Fitch, and penalized likelihood) were
used to infer the age of Crypteroniaceae using both paleobotanical and
geologic calibrations. Comparisons among these three methods revealed
significant lineage effects in rbcL sequences. Our results
argue for an ancient Gondwanan origin of Crypteroniaceae in the Early
to Middle Cretaceous, followed by diversification on the rafting
Indian plate in the Early Tertiary and subsequent dispersal to SE
Asia. These findings are congruent with recent molecular dating
estimates in vertebrates that similarly point to a central role for
India in importing Gondwanan elements into Asia.
Key words: biogeography, Crypteroniaceae, molecular dating, Myrtales, penalized likelihood