Basal birds from China: a brief review

We use the term "basal birds" for a relatively small number of primitive fossil birds that fall outside the major clade Ornithothoraces, which includes both modern birds and enantiornithines. Eight genera and twelve valid species have been reported from China in the last 15 years, whereas Archaeopteryx lithographica remains the only basal bird to have been described from non-Chinese specimens (although confuciusornithid material is apparently present in North Korea). Here we briefly review the Chinese basal birds and their anatomy, phylogeny and ecology. Chinese fossils have contributed extensively to scientific understanding of early avian evolution, demonstrating collectively that basal birds were generally relatively large and morphologically and ecologically quite diverse. Although some significant uncertainties remain, particularly with respect to the relative phylogenetic positions of Jeholornis, Sapeornis and Zhongornis, an increasingly clear picture of the first stages of avian evolution is emerging from the Chinese fossil record.