Medullary bone found in Cretaceous birds
(PHYSorg.com Archaeology & Fossils)

A team of scientists led by Jingmai O`Connor from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, reported the first occurrence of medullary bone in Enantiornithes, the dominant clade of birds during the Cretaceous. The findings were published in Nature Communications on Dec. 5.