MBE Advance Access published online on July 24, 2008
Molecular Biology and Evolution, doi:10.1093/molbev/msn160
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Research Article |
A Multi-locus Molecular Phylogeny of the Parrots (Psittaciformes): Support for a Gondwanan Origin During the Cretaceous
New Mexico State University and Smithsonian National Museum of Natural History
2 Genetics Program, National Museum of Natural History & National Zoological Park, Smithsonian Institution, 3001 Connecticut Ave., NW, Washington, DC 20008-0551
3 Departmento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brasil
4 Department of Biology and Museum of Natural Science, Louisiana State University, Baton Rouge, LA 70803
5 Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013
6 National Institute of Toxicology and Forensic Science, 38320 Tenerife, Spain
7 Department of Veterinary Medicine, Loro Parque Fundación, 3840 Puerto de la Cruz, Tenerife, Spain
8 School of Biological Sciences, Victoria University, PO Box 600, Wellington 6140, New Zealand
1 Corresponding author: Department of Biology, New Mexico State University, Las Cruces, NM 88003, wright{at}nmsu.edu, phone 505-646-1136, fax 505-646-5665
Received for publication February 27, 2008. Revision received June 9, 2008. Accepted for publication July 18, 2008.
The question of when modern birds (Neornithes) first diversified has generated much debate among avian systematists. Fossil evidence generally supports a Tertiary diversification, while estimates based on molecular dating favor an earlier diversification in the Cretaceous period. In this study we used an alternate approach, the inference of historical biogeographic patterns, to test the hypothesis that the initial radiation of the Order Psittaciformes (the parrots and cockatoos) originated on the Gondwana supercontinent during the Cretaceous. We utilized broad taxonomic sampling (representatives of 69 of the 82 extant genera and eight outgroup taxa) and multi-locus molecular character sampling (3941 bp from mtDNA genes COI and NADH2 and nuclear introns of RDPSN, TROP, TGFB2) to generate phylogenetic hypotheses for the Psittaciformes. Analyses of the combined character partitions using maximum parsimony, maximum likelihood and Bayesian criteria produced well-resolved and topologically similar trees in which the New Zealand taxon Nestor (Psittacidae) was sister to all other psittaciforms, and the cockatoo clade (Cacatuidae) was sister to a clade containing all remaining parrots (Psittacidae). Within this large clade of Psittacidae some traditionally recognized tribes and subfamilies were monophyletic (e.g. Arini, Psittacini, and Loriinae) while several others were polyphyletic (e.g. Cyclopsittacini, Platycercini, Psittaculini and Psittacinae). Ancestral area reconstructions using our Bayesian phylogenetic hypothesis and current distributions of genera supported the hypothesis of an Australasian origin for the Psittaciformes. Separate analyses of the timing of parrot diversification constructed with both Bayesian relaxed-clock and penalized likelihood approaches showed better agreement between geologic and diversification events in the chronograms based on a Cretaceous dating of the basal split within parrots than the chronograms based on a Tertiary dating of this split, although these data are more equivocal. Taken together, our results support a Cretaceous origin of Psittaciformes in Gondwana after the separation of Africa and the India/Madagascar block with subsequent diversification through both vicariance and dispersal. These well-resolved molecular phylogenies will be of value for comparative studies of behavior, ecology and life history in parrots.
Key Words: Cretaceous origin • divergence times • Gondwanan distribution • K/T boundary • molecular phylogeny • parrot • Psittaciformes • Tertiary origin