page_title: Eomaia
section_title: Classification
hierarchical_section_title: Eomaia / Classification
caption_attribution_description: Italiano: Fossil of Eomaia, an extinct mammal- Took the photo at Musee d'Histoire Naturelle, Paris
context_page_description: Eomaia is a genus of extinct fossil mammals containing the single species Eomaia scansoria, discovered in rocks that were found in the Yixian Formation, Liaoning Province, China, and dated to the Barremian Age of the Lower Cretaceous about 125 million years ago. The single fossil specimen of this species is 10 centimetres in length and virtually complete. An estimate of the body weight is between 20–25 grams. It is exceptionally well-preserved for a 125-million-year-old specimen. Although the fossil's skull is squashed flat, its teeth, tiny foot bones, cartilages and even its fur are visible.
context_section_description: The discoverers of Eomaia claimed that, on the basis of 268 characters sampled from all major Mesozoic mammal clades and principal eutherian families of the Cretaceous, Eomaia could be placed at the root of the eutherian "family tree" along  with Murtoilestes and Prokennalestes. This initial classification scheme is summarized below.
   
  In 2013, a much larger study of mammal relationships (including fossil species) was published by Maureen O'Leary and colleagues. 
  The study, which examined 4541 anatomical characters of 86 mammal species (including Eomaia scansoria), found "100% jackknife support that Eomaia falls outside of Eutheria as a stem taxon to Theria", and so could not be considered a placental or a eutherian as previously believed. The results of this study are summarized in the cladogram below.
  The 2013 study by O'Leary et al. is controversial.
  The original classification of Eomaia as a eutherian mammal is still widely accepted.
caption: Fossil cast
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