Zhongjianornis an enlarged, keeled breastbone in more advanced birds. However, later analysis of the anatomy of "Z. yangi" cast doubt on this interpretation of the bird as very primitive. Research published in 2012 found that some of the apparently primitive features were due to poor preservation of the bones, and that "Zhongjianornis" is more similar in anatomy to primitive euornitheans like "Chaoyangia" and "Schizooura". A phylogenetic analysis showed that a very primitive position in the bird family tree for "Z. yangi" is unlikely given current evidence. Zhongjianornis Zhongjianornis is a genus of beaked, pigeon-sized birds from the early Cretaceous period of
Pan American Association of Anatomy are: International Journal of Morphology (Revista Internacional de Morfología), Brazilian Journal of Morphology Sciences, Venezuelan Magazine of Morphological Sciences and Medical Journal of Costa Rica and Central America. Headquarters, dates and presidencies: Headquarters, dates and presidencies: Pan American Association of Anatomy The Pan American Association of Anatomy (PAA) is a public, nonprofit, scientific organization that brings together professionals engaged in the study of Anatomy and related sciences in the American continent. The Pan American Association of Anatomy (PAA) was created in July 1966 in Mexico City at the 1st Pan American Congress of Anatomy, which was held together with the