'Land Birds'John Harshman
This tree diagram shows the relationships between several groups of organisms.
The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.
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Summary phylogenetic hypothesis for avian orders based on Hackett et al. (2008) and Ericson et al. (2006).
"Land Birds" is an informal name for a large and diverse group supported only by molecular characters (Hackett et al. 2008, Ericson et al. 2006). It encompasses most — though by no means all — of the familiar groups of land birds, including the largest order, Passeriformes, which comprises over half of all bird species. This group and relationships within it are a considerable departure from previous phylogenetic hypotheses and classifications, and some explanation is necessary.
Two traditional orders, Falconiformes and Coraciiformes, have been split. The family Falconidae (falcons) is not a close relative of the remaining falconiforms, and thus Falconiformes is limited to a single family (the falcons). The remaining birds of prey traditionally included within Falconiformes have been given their own order, Accipitriformes. Accipitriformes includes Cathartidae (New World vultures), which have often been supposed to be more closely related to Ciconiidae (storks).
Coraciiformes as traditionally defined includes both Bucerotiformes and Leptosomatidae. But if these groups were retained in the order, two additional orders, Piciformes and Trogoniformes, would also have to be submerged within it to maintain monophyly.
"Land Birds" holds other surprises. There has long been controversy about which group should be considered the closest relatives of Passeriformes. Traditional candidates have included Coraciiformes, Piciformes, Coliiformes, and Columbiformes (doves, which do not in fact belong to "Land Birds"). Psittaciformes and Falconiformes had not previously been suggested, and while further confirmation is needed, current molecular data show strong support for this grouping. Cariamidae (seriemas), traditionally considered to belong to Gruiformes, may also be closer to Passeriformes than to most other "Land Birds", though the support for this is not strong.
Ericson, P. G. P., C. L. Anderson, T. Britton, A. Elzanowski, U. S. Johansson, M. Kallersjo, J. I. Ohlson, T. J. Parsons, D. Zuccon, G. Mayr. 2006. Diversification of Neoaves: integration of molecular sequence data and fossils. Biology Letters 2(4):543-547.
Hackett, S. J., Kimball, R. T., Reddy, S., Bowie, R. C. K., Braun, E. L., Braun, M. J., Chojnowski, J. L., Cox, W. A., Han, K.-L., Harshman, J., Huddleston, C. J., Marks, B. D., Miglia, K. J., Moore, W. A., Sheldon, F. H., Steadman, D. W., Witt, C. C., and Yuri, T. 2008. A phylogenomic study of birds reveals their evolutionary history. Science 320(5884):1763-1768.
Correspondence regarding this page should be directed to John Harshman at
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- First online 27 June 2008
- Content changed 27 June 2008
Citing this page:
Harshman, John. 2008. 'Land Birds'. Version 27 June 2008 (under construction). http://tolweb.org/%27Land_Birds%27/26410/2008.06.27 in The Tree of Life Web Project, http://tolweb.org/