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The discovery of the fossilized remains of a previously unknown dinosaur found in a layer of the Ukureyskaya formation from a site called Kulinda, on the banks of the Olov River in the Zibaikalsky Krai region of southeastern Siberia (Russia), and dated at roughly 160 myo (Late Jurassic), is causing researchers to reexamine what they know about feathered dinosaurs in that it provides evidence that feathers were more widespread than previously thought.
Since the 1980s discoveries made primarily in northeastern China have produced several species of feathered dinosaurs, but they all belonged to the suborder of dinosaurs known as Theropoda, a primarily carnivorous group that first arose during the Late Triassic and thought to be the ancestors of modern birds.
But now an international team of researchers has reported in the journal Science the discovery of a new genus and species of an herbivorous dinosaur that is the first non-theropod to show conclusive evidence of having sported feathers.
This new dinosaur is called [i]Kulindadromeus zabaikalicus[i], with the generic name combining the name of the Kulinda site with the Greek word for "runner" (dromeus). The second part, or species name refers to the Zabaikal region. So essentially [i]Kulindadromeus zabaikalicus[i] means "Kulinda River running dinosaur."
It has been identified as being a basal member of the Neornithischia, an early type of ornithischian, an extinct type of plant-eating beaked dinosaur known as the "bird-hipped" dinosaurs because of their bird-like hip structure (even though birds are actually more closely related to the Saurischia, or "lizard-hipped" dinosaurs, than to the ornithischian dinosaurs).
Since Kulindadromeus belongs to a group other than theropods and displays evidence of having possessed both scales and feather-like structures this discovery indicates that plumage was present in a far greater number of species than previously thought and suggests that most and even possibly all dinosaurs had feathers.
As the lead author of the paper describing the discovery, paleontologist Pascal Godefroit of the Royal Belgian Institute of Natural Science in Brussels, said that "for the first time, we have found featherlike structures in a dinosaur is far from the lineage leading to birds," and added "probably that means the common ancestor of all dinosaurs had feathers."
According to Godefroit Kulindadromeus "was a small animal, not very impressive." Like other early neornithischians it was a bipedal creature, approximately 1.5 meters (just under 5') long with a short snout full of teeth clearly adapted to a herbivorous diet.
Kulindadromeus had a tail covered in large, thin scales and long, slender hindlimbs along with short forelimbs ending in strong digits.
The remains were exceptionally well preserved in volcanic ash in what was once a lake bottom and is now a Siberian hillside. They consist of six skulls, and hundreds of disarticulated skeletons found in two bone beds.
The researchers found three different types of feather-like structures which covered a large portions of Kulindadromeus' body.
The first type consists of simple thread-like monofilaments covering the trunk, thorax and head. These thin, bristle-like feathers are up to 3 cm (1") long and resemble the "dino-fuzz" previously seen in theropods like Sinosauropteryx.
The second type are composed of long filaments resembling downy feathers and found around the humerus, the femur, and the tibia. They were up to 1.5 cm (½") long and projected downwards in a compound structure of six or seven filaments from a base plate that are ordered in a hexagonal pattern but do not touch each other.
The third type were found on the upper portion of the lower limbs which were largely covered in reptile-like scales and are of a sort never seen prior to this. These unique feathers are comprised of bundles of six or seven “ribbon-shaped elements” or structures, up to 2 cm (¾") long. Each of these ribbons is made up of around ten parallel filaments that are up to 0.1 mm (0.004") wide.
The researchers think that since Kulindadromeus couldn't fly (nothing resembling flight feathers, short forelimbs) that the first two types of feathers likely served as insulation while the third may have been useful in attracting mates.
As noted above, bristly, hair-like monofilament type feathers that appear to have been slightly longer than those seen Kulindadromeus have previously been reported in ornithischian dinosaur discoveries (Psittacosaurus and Tianyulong), both from China, but the evidence was inconclusive. Moreover no other ornithischian has shown any indication of possessing feathers composed of multiple filaments.
As Dave Hone, a paleontologist and lecturer at the University of London's School of Biological and Chemical Sciences points out, "the fact that multiple filament types are turning up in a single species, and that this includes multiple filaments from a single point of origin really make it clear that more structurally complex coverings close to feathers are not exclusive to theropods."
Still as Godefroit and his colleagues are quick to point out more fossils must be found in order to determine if other groups of dinosaurs besides theropods and ornithischians had feathers.
And it should be noted that some scientists, like Brian Switek, while appearing optimistic wrt to the discovery, still want more definitive evidence that they are true feathers rather than feather-like structures (but that is how science works -- always wanting more evidence). Others, like Paul Barrett of the Natural History Museum in London, is more dobtful.
"Most feathers have a branching structure," he said. "Instead these look like little streamers coming from a central plate. No bird has that structure in any part of its plumage and none of the developmental models that biologists use to understand the evolution of feathers includes a stage that has anything like that kind of anatomy." Of course nobody is saying that these structures led to bird feathers and the ribbon-like ones might even have been dead-ends (thereby explaining their uniqueness)
Further Reading:
A Jurassic ornithischian dinosaur from Siberia with both feathers and scales Abstract
Siberian Discovery Suggests Almost All Dinosaurs Were Feathered
Siberian dinosaur spreads feathers around the dinosaur tree
Ancestors of birds were not the only dinosaurs with feathers includes 2½ min vid
Downy Beast Suggests All Dinos Sported Feathers
Fossils Found in Siberia Suggest All Dinosaurs had Feathers
Fluffy Dinosaur Raises Questions About the Origin of Dinofuzz
Jurassic aviary: New fossil suggests that all dinosaurs sported feathers
Newly Discovered Fossils Suggest That All Dinosaurs May Have Had Feathers
'Fluffy and feathery' dinosaurs were widespread
Since the 1980s discoveries made primarily in northeastern China have produced several species of feathered dinosaurs, but they all belonged to the suborder of dinosaurs known as Theropoda, a primarily carnivorous group that first arose during the Late Triassic and thought to be the ancestors of modern birds.
But now an international team of researchers has reported in the journal Science the discovery of a new genus and species of an herbivorous dinosaur that is the first non-theropod to show conclusive evidence of having sported feathers.
This new dinosaur is called [i]Kulindadromeus zabaikalicus[i], with the generic name combining the name of the Kulinda site with the Greek word for "runner" (dromeus). The second part, or species name refers to the Zabaikal region. So essentially [i]Kulindadromeus zabaikalicus[i] means "Kulinda River running dinosaur."
It has been identified as being a basal member of the Neornithischia, an early type of ornithischian, an extinct type of plant-eating beaked dinosaur known as the "bird-hipped" dinosaurs because of their bird-like hip structure (even though birds are actually more closely related to the Saurischia, or "lizard-hipped" dinosaurs, than to the ornithischian dinosaurs).
Since Kulindadromeus belongs to a group other than theropods and displays evidence of having possessed both scales and feather-like structures this discovery indicates that plumage was present in a far greater number of species than previously thought and suggests that most and even possibly all dinosaurs had feathers.
As the lead author of the paper describing the discovery, paleontologist Pascal Godefroit of the Royal Belgian Institute of Natural Science in Brussels, said that "for the first time, we have found featherlike structures in a dinosaur is far from the lineage leading to birds," and added "probably that means the common ancestor of all dinosaurs had feathers."
According to Godefroit Kulindadromeus "was a small animal, not very impressive." Like other early neornithischians it was a bipedal creature, approximately 1.5 meters (just under 5') long with a short snout full of teeth clearly adapted to a herbivorous diet.
Kulindadromeus had a tail covered in large, thin scales and long, slender hindlimbs along with short forelimbs ending in strong digits.
The remains were exceptionally well preserved in volcanic ash in what was once a lake bottom and is now a Siberian hillside. They consist of six skulls, and hundreds of disarticulated skeletons found in two bone beds.
The researchers found three different types of feather-like structures which covered a large portions of Kulindadromeus' body.
The first type consists of simple thread-like monofilaments covering the trunk, thorax and head. These thin, bristle-like feathers are up to 3 cm (1") long and resemble the "dino-fuzz" previously seen in theropods like Sinosauropteryx.
The second type are composed of long filaments resembling downy feathers and found around the humerus, the femur, and the tibia. They were up to 1.5 cm (½") long and projected downwards in a compound structure of six or seven filaments from a base plate that are ordered in a hexagonal pattern but do not touch each other.
The third type were found on the upper portion of the lower limbs which were largely covered in reptile-like scales and are of a sort never seen prior to this. These unique feathers are comprised of bundles of six or seven “ribbon-shaped elements” or structures, up to 2 cm (¾") long. Each of these ribbons is made up of around ten parallel filaments that are up to 0.1 mm (0.004") wide.
The researchers think that since Kulindadromeus couldn't fly (nothing resembling flight feathers, short forelimbs) that the first two types of feathers likely served as insulation while the third may have been useful in attracting mates.
As noted above, bristly, hair-like monofilament type feathers that appear to have been slightly longer than those seen Kulindadromeus have previously been reported in ornithischian dinosaur discoveries (Psittacosaurus and Tianyulong), both from China, but the evidence was inconclusive. Moreover no other ornithischian has shown any indication of possessing feathers composed of multiple filaments.
As Dave Hone, a paleontologist and lecturer at the University of London's School of Biological and Chemical Sciences points out, "the fact that multiple filament types are turning up in a single species, and that this includes multiple filaments from a single point of origin really make it clear that more structurally complex coverings close to feathers are not exclusive to theropods."
Still as Godefroit and his colleagues are quick to point out more fossils must be found in order to determine if other groups of dinosaurs besides theropods and ornithischians had feathers.
And it should be noted that some scientists, like Brian Switek, while appearing optimistic wrt to the discovery, still want more definitive evidence that they are true feathers rather than feather-like structures (but that is how science works -- always wanting more evidence). Others, like Paul Barrett of the Natural History Museum in London, is more dobtful.
"Most feathers have a branching structure," he said. "Instead these look like little streamers coming from a central plate. No bird has that structure in any part of its plumage and none of the developmental models that biologists use to understand the evolution of feathers includes a stage that has anything like that kind of anatomy." Of course nobody is saying that these structures led to bird feathers and the ribbon-like ones might even have been dead-ends (thereby explaining their uniqueness)
Further Reading:
A Jurassic ornithischian dinosaur from Siberia with both feathers and scales Abstract
Siberian Discovery Suggests Almost All Dinosaurs Were Feathered
Siberian dinosaur spreads feathers around the dinosaur tree
Ancestors of birds were not the only dinosaurs with feathers includes 2½ min vid
Downy Beast Suggests All Dinos Sported Feathers
Fossils Found in Siberia Suggest All Dinosaurs had Feathers
Fluffy Dinosaur Raises Questions About the Origin of Dinofuzz
Jurassic aviary: New fossil suggests that all dinosaurs sported feathers
Newly Discovered Fossils Suggest That All Dinosaurs May Have Had Feathers
'Fluffy and feathery' dinosaurs were widespread
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