The bones of a dinosaur with peculiar bird-like traits has been discovered
by scientists in a fossil bed in southeast China, among the remnants of
preserved fish and turtles.
The discovery, which is thought to be around 30 million years older than
any verified avian fossil, may provide some important insights into the
early stages of bird development.Paleontologist Min Wang of the Chinese
Academy of Sciences and associates determined the new fossil's position in
the dino-bird family tree by comparing it to the skeletal remains of other
extant and extinct dinosaurs. The new fossil was called Fujianvenator
prodigiosus.
The pheasant-sized and probably feathered Fujianvenator prodigiosus,
according to the researchers, belonged to the ancestral group avialae, which
is comprised of current birds and the closest dinosaur predecessors to
them.
Such fossilized remains of our earliest bird predecessors are rare and
valuable windows into the development of birds and their Earthly
environments.
To acknowledge the remarkable diversity and distinctive composition found
at that particular period and location in Earth's history, researchers have
called the collection Fujianvenator, which was discovered in Zhenghe
Fauna.
The 150 million-year-old fossilized bones of the dinosaur Archaeopteryx
characterized an important early stage in the evolution of modern birds for
many years.
Researchers are now less certain, discovering that the renowned feathered
species shares more similarities with Deinonychosauria than with Avialae.
Because there aren't many other credible fossils from this era that resemble
birds, scientists can only speculate as to what an early bird would have
looked like.
Situated halfway between extinct dinosaurs and contemporary birds,
Fujianvenator may hold some clues. It appeared only a few million years
after
Archaeopteryx.
The peculiar four-winged
Anchiornis
and other dinosaurs with fewer bird-like traits are more comparable to the
pelvis of Fujianvenator. This indicates that the morphological shift from
arms to wings occurred very early in the evolutionary history of birds,
while their legs were still performing distinct functions. It also implies
that Fujianvenator diverged from the line that gave rise to birds.
"Our comparative analyses demonstrate that significant changes in body
plan, primarily driven by the forelimb, occurred along the early avialan
line, ultimately giving rise to the typical bird limb proportion,"
says Wang.
"Fujanvenator, on the other hand, is a peculiar species that deviated from
this primary trajectory and evolved an unusual hindlimb architecture."
Given its lengthy hindlimbs and the fossils it was discovered with,
Fujianvenator may have been a fast runner or a long-legged marsh
dweller.
These leg proportions are used for both sprinting and wading; sadly,
Fujianvenator's feet, which may help distinguish between these activities,
are not well-defined, thus more fossil discoveries will be required to
corroborate this.
However, this is the first time that an identified potential swamp avialan
has been found. The remaining avialans that paleontologists have found thus
far all exhibit characteristics of tree dwellers.
This research was published in
Nature.
