Sapeornis

Name: Sapeornis ‭(‬SAPE bird‭).
Phonetic: Sape-or-niss.
Named By: Zhou‭ & ‬Zhang‭ ‬-‭ ‬2002.
Synonyms: Didactylornis,‭ ‬Sapeornis angustis,‭ ‬Shenshiornis primita.‭ ‬Possibly also Omnivoropteryx.
Classification: Chordata,‭ ‬Aves,‭ ‬Omnivoropterygiformes,‭ ‬Omnivoropterygidae.
Species: S.‭ ‬chaoyangensis‭ (‬type‭)‬.
Diet: Herbivore/Omnivore‭?
Size: About‭ ‬30-33‭ ‬centimetres long.
Known locations: China,‭ ‬Liaoning Province‭ ‬-‭ ‬Jiufotang Formation‭ & ‬Yixian Formation.
Time period: Aptian of the Cretaceous.
Fossil representation: Several individuals.




       Sapeornis is named from a combination of SAPE and the Ancient Greek‭ ‘‬ornis‭’ ‬which means bird.‭ ‬SAPE is actually an acronym for the Society of Avian Palaeontology and Evolution.‭ ‬Also in‭ ‬2002‭ ‬another genus of bird named Omnivoropteryx was created by Stephen Czerkas and Qiang Ji.‭ ‬Omnivoropteryx was established as being separate to Sapeornis by the authors on the basis that the pubis is longer.‭ ‬At the time Sapeornis was not known by skull material and while Omnivoropteryx was,‭ ‬it was treated as valid.‭ ‬Since the naming however,‭ ‬skulls for Sapeornis have now been found,‭ ‬and these are near identical to the skull of Omnivoropteryx,‭ ‬which means that the only clear difference between the two genera is the length of the pubis.‭ ‬This has now led to speculation that Omnivoropteryx should become a synonym to Sapeornis,‭ ‬perhaps at a new species level as opposed to a separate genus.
       Like with many of the early birds living in China during the early Cretaceous,‭ ‬Sapeornis shows a mix of characteristics that place it at some point between the early bird forms of the late Jurassic such as Archaeopteryx,‭ ‬and the more advanced bird forms that became prevalent towards the end of the late Cretaceous.‭ ‬Sapeornis had a rod-like pygostyle similar to Confuciusornis,‭ ‬though Sapeornis might have actually had a small number of‭ ‬tail flight feathers.‭ ‬Overall while the wings could have‭ ‬definitely been used for gliding,‭ ‬they did not have the same range of motion as modern birds and may have only been capable of limited flapping ability.‭ ‬The presence of a deeply keeled sternum to support strong pectoral muscles for flapping is still uncertain as one has not been found.
       Sapeornis only had a small number of teeth that were present in the anterior tip of the upper jaw.‭ ‬Sapeornis is also known to have used gastroliths‭ (‬small stones swallowed to help break up food‭)‬,‭ ‬indicating that Sapeornis may have eaten harder food such as seeds.‭ ‬Sapeornis would not be the only early bird to do so as a seed eating diet has been confirmed for Jeholornis too.‭ ‬Like with most basal birds‭ (‬and theropod dinosaurs‭)‬,‭ ‬Sapeornis grew very slowly at first,‭ ‬before entering a rapid growth spurt upon approaching sexual maturity.‭ ‬Scleral ring analysis of Sapeornis indicates that it was diurnal,‭ ‬that is,‭ ‬active only during the daytime.




Further reading
-‭ ‬Anatomy of the primitive bird Sapeornis chaoyangensis from the Early Cretaceous of Liaoning,‭ ‬China.‭ ‬-‭ ‬Zhonghe Zhou‭ & ‬Fucheng Zhang‭ ‬-‭ ‬2003.
-‭ ‬Scapular orientation in theropods and basal birds,‭ ‬and the origin of flapping flight‭ ‬-‭ ‬P.‭ ‬Senter‭ ‬-‭ ‬2006.‭ ‬-‭ ‬Zhonghe Zhou‭ & ‬Fucheng Zhang‭ ‬-‭ ‬2006.
-‭ ‬A new sapeornithid bird from China and its implication for early avian evolution.‭ ‬-‭ ‬D.‭ ‬hu etal‭ ‬-‭ ‬2010.
-‭ ‬Nocturnality in Dinosaurs Inferred from Scleral Ring and Orbit Morphology.‭ ‬-‭ ‬L.‭ ‬Schmitz‭ & ‬R.‭ ‬Motani‭ ‬-‭ ‬2011.
- A subadult specimen of the Early Cretaceous bird Sapeornis chaoyangensis and a taxonomic reassessment of sapeornithids. - Journal of Vertebrate Paleontology. 32 (5): 1103–1112. - C. Gao, L. M. Chiappe, F. Zhang, D. L. Pomeroy, C. Shen, A. Chinsamy & M. O. Walsh - 2012.
- Comment on the absence of ossified sternal elements in basal paravian dinosaurs. - Proceedings of the National Academy of Sciences, 111(50): E5334-E5334. - C. Foth - 2014.

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