Ratites

From EvoWiki

Ratites, refers the assemblage of paleognathous, flightless birds including Struthionidae (ostriches), Dromiceidae (emus), Rheidae (rheas), Apterygidae (kiwis), and Casuariidae (cassowaries), and among extinct forms, moas and Malagasy elephant birds.. Ratitae has classically been considered a holophyletic taxon, first proposed as such on the basis of palatal configuration (paleognathous palate) by Thomas Huxley in 1867.

Since this time the phylogeny of these spectacular birds has been acrimoniously debated, with a variety of hypotheses expressed.

1. The modernist era saw the widespread conclusion that ratites are in fact a paraphyletic or polyphyletic grouping, most eloquently advanced by the work of the legendary Gavin de Beer of the British Museum of Natural History, Alexander Wetmore, equally renowned, of the Smithsonian, Ernst Mayr--dean of the Modern Synthesis and Dean Amadon, as well as others. Wetmore and de Beer both argued for the secondarily paleognathous, neognath derivation of ratites.
2. In a curious sort of deja vu, in 1974 enterprising cladist and paleornithologist Joel Cracraft engineered a cladistic analysis of Ratitae to test his infamous "vicariance biogeographic hypothesis" and concluded that Ratitae is in fact holophyletic, a viewpoint since championed by Bledsoe (1988), no less an authority than Walter Bock of Columbia and his colleague Paul Buhler (1988), Sibley & Ahlquist (1990) and Chatterjee (1997).
3. Nevertheless, the discovery and description of the magnificent Lithornithiformes by Houde and Olson (1981, see further work by Houde 1988) has argued convincingly for the polyphyly of Ratitae as classically defined. Holophyly of Ratitae must be seriously questioned considering the failure of any analysis upholding its phylogenetic unity to isolate synapomorphic characters with which to unite the ratites, and the leading hypothesis for ratite holophyly, Cracraft's zoogeographic model, is entirely refuted by the fossil record of these birds, and this researcher's proposed phylogeny of Ratitae is pure fiction.

JGK