Caudipteryx
Name:
Caudipteryx
(tail feather).
Phonetic: Caw-dip-teh-rix.
Named By: Q. Ji, P. J. Currie, M. A.
Norrel & S. Ji - 1998.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Oviraptorosauria, Caudipteridae.
Species: C. zoui (type), C.
dongi.
Diet: Omnivore?
Size: Up to about 1 meter long.
Known locations: China, Liaoning Province -
Yixian Formation.
Time period: Aptian of the Cretaceous.
Fossil representation: Several specimens.
Caudipteryx
the animal.
Caudipteryx
is one of the most primitive oviraptosaurs
so far known to us, only
the genus Incisivosaurus
is known to be older at the time of writing.
The skull of Caudipteryx can be easily described
as being box-like,
and the jaws are already formed into a beak. Teeth are still present
however in the anterior portion of the upper jaw. The legs are fairly
long and well-built indicating that Caudipteryx was
a capable runner.
Caudipteryx
is confirmed to have had a covering of downy feathers all over its
body, the presence of which was almost certainly for insulation.
Arrangements of larger twenty centimetre long feathers are known to
have existed upon the arms however. These feathers had vanes for
increased rigidity as well as barbs so that they all connected
together, and are seen as analogous to the first set of flight
feathers of birds. Only one row has been confirmed as present so
far, and that fact combined with the overall shape of Caudipteryx
has
yielded the conclusion that this row of feathers was not capable of
producing flight, and thus were probably present more as a display or
perhaps steering purpose when turning while running at high speed.
How is Caudipteryx
related to
dinosaurs and birds?
As
a feathered dinosaur Caudipteryx is just one of
many that are confirmed
as having feathers. However the primitive features of Caudipteryx
have blurred the line between what constitutes a dinosaur and what
constitutes a bird. There is now a clear split between
palaeontologists with some considering that Caudipteryx
is a non-avian
dinosaur, while others consider it a bird. There are now a
multitude of variations of these theories, but they can generally be
labelled under two areas.
Option 1 - Caudipteryx
is
an oviraptosaur and directly descended from non-avian dinosaurs.
Caudipteryx
is an oviraptosaur, a member of the oviraptosauria that as a group
was founded upon the description of Oviraptor.
Since the
establishment of this group in 1976 by Rinchen Barsbold, the
oviraptosaurs have been considered a sub group of the what we now call
the Maniraptora (set up in 1986). The maniraptoria is the home
for many other kinds of feathered dinosaurs and was considered to be
the probable origin of the birds. Members of this group are thought
to have evolved from the theropod dinosaurs of the saurischian line.
The
oviraptosaurs are often interpreted as one line of feathered dinosaurs
descended from this group, and under this interpretation,
Caudipteryx and its relatives are classed as
dinosaurs. This is
because a clear line can be drawn between the development of theropod
dinosaurs and later oviraptosaurs. The presence of feathers on
oviraptosaurs like Caudipteryx has been seen as a
sign that these
dinosaurs evolved from similar ancestors as birds.
Option 2 - Caudipteryx
is
an oviraptosaur and directly descended from birds.
Many
researchers have pointed out that Caudipteryx is
more bird like and may
actually be descended from actual birds. In this scenario birds
would have already evolved from dinosaurs with features that clearly
identify them as birds. One group of these birds however regressed in
evolutionary terms so that more dinosaur-like characteristics
re-appeared. This is not that far-fetched an idea as all researches
will concede that evolution in animals doesn’t always go one way,
and that more primitive forms can re-appear if ecological conditions
drive a creature to do so.
A
bird ancestry might more easily explain the presence of large feathers
on the arm. A bird ancestor would not necessarily have to be capable
of flight, but has been recognised that if oviraptosaurs are evolved
from birds the n they might be secondarily -flightless. This is a
controversial theory as at the time of writing it flies into the face
of longer accepted thinking, but if this is true then two things
might happen. The first is that birds would not just be descended
from dinosaurs, they would technically ‘be’ dinosaurs. The only
other alternative would be to re-classify oviraptosaurs and possibly
other kinds of maniraptorans as ‘birds’ and not ‘dinosaurs’.
Caudipteryx in
the Yixian
Formation
Caudipteryx
is one of many feathered creatures from the now famous Yixian Formation
which has yielded the discoveries of many feathered dinosaurs and
primitive birds alike. Caudipteryx seems to have
been quite common,
though as of 2014 fossils for the genus are only known from the
Yixian Formation, which might suggest a dense but localised
population. Other creatures from the Yixian Fomation that Caudipteryx
may have lived alongside include dinosaurs such as Dilong,
Beipiaosaurus,
Sinocalliopteryx,
Yutyrannus,
Sinornithosaurus
and Tianyuraptor,
birds such as Confuciusornis,
Jixiangornis and
Zhongornis, and pterosaurs
such as Feilongus,
Boreopterus
and
Zhenyuanopterus.
Further reading
- Two feathered dinosaurs from northeastern China - Nature 393
(6687): 753–761 - Q. Ji, P. J. Currie, M. A.
Norrel & S. Ji - 1998.
- A new species of Caudipteryx from the Yixian
Formation of
Liaoning, northeast China. - Vertebrata Palasiatica 38
(2): 113–130. - Z. Zhou & X. Wang - 2000.
- Important features of Caudipteryx -
Evidence from two nearly
complete new specimens. - Vertebrata Palasiatica 38 (4):
241–254. - Z. Zhou, X. Wang, F. Zhang & X.
Xu - 2000.
- Dinosaurs of the Air: The Evolution and Loss of Flight in
Dinosaurs and Birds. Johns Hopkins University Press (ISBN
0-8018-6763-0) - Gregory S. Paul - 2002.
- Avialan status for Oviraptorosauria. - Acta Palaeontologica
Polonica 47 (1): 97–116. - T. Maryańska, H.
Osmólska & M. Wolsan - 2002.
- Oviraptorosaurs compared to birds. - J. Lü, Z. Dong,
Y. Azuma, R. Barsbold & Y. Tomida - In,
Proceedings of the 5th Symposium of the Society of Avian
Paleontology and Evolution, 175–189. Z. Zhou & F.
Zhang (eds.). Beijing Science Press. - 2002.
- The Dinosauria Weishampel, Dodson, Osmolska. - Chapter 8
Oviraptorosauria - University of California Press. - Halszka
Osmólska, Philip J. Currie & Rinchen Barsbold - 2004.
- The Debate on Avian Ancestry; Phylogeny, Function and Fossils
- Mesozoic Birds: Above the Heads of Dinosaurs (ISBN
0-520-20094-2) : 3–30. - Lawrence M. Witmer - 2005.
- Caudipteryx as a non-avialan theropod rather
than a flightless
bird. - Acta Palaeontologica Polonica 50 (1): 101–116.
- Gareth J. Dyke & Mark A. Norell - 2005.
- Non-Avian dinosaur fossils from the Lower Cretaceous Jehol Group of
western Liaoning, China - Geological Journal 41: 419–437.
- X. Xu & M. A. Norell - 2006.
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