The phylogeny of the living and fossil Palaeognathae

KSEPKA, D.T.; BERTELLI, S.; DYKE, G.J.; CRACRAFT, J.

Mesa, Arizona

Congreso; Sixty-Fifth Annual Meeting of the Society of Vertebrate Paleontology; 2005

Society of Vertebrate Paleontology

The Palaeognathae, the sister group to all other neomithine birds, comprises the large,flightless Ratitae and the volant Tinamidae and Lithomithidae. Because eatire clades(Lithornithidae, Dinornithiformes, Aepyornithidae} and landmasses (Madagascar) are represented only by extinct taxa, inclusion of data from fossils is crucial for an Understanding of palaeognaüi phylogeny and biogeography. We conducted a morphology-based phylogenetic analysis of the Paiaeognathae,incorporating all extant genera and the fossil taxa Aepyornis,Mitllerornif, Palaeotix. Lithornis, Pxeudocrypturus. Paracathartes and five dinornithiform (moa) genera. Ourmatrixof osteological, integumentary and oological characters is Ihe first to sample nearly all palaeognaths at the generic leve! and more than doubles the oumber of characters used in previous analyses. In particular, we utilized a suite of 67 cranial characters, the majority never before included in a cladistic analysis of the group. Aheurisüc search using TNT recovered3 raost parsimonious trees. Ourresults confirm the monophyly of the Tinamidae, Lithornithidae, and Ratitae, and support a sister group relaüonship between the latter two clades. The probtem of radte phylogeny is one of the classic examples of confliet between morphologicaf and molecular data, and our expanded data set bighlights areas of confliet by providing new character support for raany morphology-based clades, Within Ratitae, our results clash with those of molecular analyses by placing Struthio and Rhea äs sister taxa rather than äs basal ratite üneage-s and by allying Apteryx wilh the Dinomithiformes radier than with the Australian ratites. These groupings were also recovered by analysis of a cranial partition of our data set, indicating they are not the result of convergences in the postcranial skeleton. A novel clade grouping theAepyorniÜiidae{elephant birds) with Apteryx and the Dinornithiformes is one of the more surprising results of our analysis.