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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