{{italictitle}}
{{italictitle}}{{Taxobox
| name =
Sinornithosaurus
| fossil_range =
Early CretaceousThe Early Cretaceous or the Lower Cretaceous , is the earlier or lower of the two major divisions of the Cretaceous...
, {{fossil range|124.6}}
| image = Sinornithosaurus millenii 2.JPG
| image_width = 200px
| image_caption =
Sinornithosaurus millenii fossil displayed in the Hong Kong Science Museum
| regnum =
AnimalAnimals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...
ia
| phylum =
ChordataChordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail...
| classis =
ReptiliaReptiles, or members of the class Reptilia, are air-breathing, generally "cold-blooded" amniotes that generally have skin covered in scales or scutes. They are tetrapods and lay amniote eggs, whose embryos are surrounded by the amnion membrane...
| superordo =
Dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
ia
| ordo =
SaurischiaSaurischia is one of the two orders, or basic divisions, of dinosaurs. In 1888, Harry Seeley classified dinosaurs into two orders, based on their hip structure...
| subordo =
TheropodaTheropods are a group of bipedal saurischian dinosaurs. Although they were primarily carnivorous, a number of theropod families evolved herbivory during the Cretaceous Period...
| familia =
DromaeosauridaeDromaeosauridae is a family of bird-like theropod dinosaurs. They were small to medium-sized, feathered carnivores that flourished in the Cretaceous Period. In informal usage they are often called "raptors" , a term popularized by the film Jurassic Park...
| genus =
Sinornithosaurus
| genus_authority =
XuXu Xing is a famed Chinese paleontologist who has named many dinosaurs, including the new Jurassic Ceratopsian Yinlong, the feathered relative of Tyrannosaurus, Guanlong, the unusual Gigantoraptor, and the "sleeping dragon" Mei. He was born in Xin Jiang, China, in 1969...
, Wang, & Wu, 1999
| subdivision_ranks =
SpeciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
| subdivision =
- S. millenii Xu, Wang, & Wu, 1999 (type)
- S. haoiana Liu J., Ji S., Tang F., & Gao C., 2004
}}
Sinornithosaurus (derived from a combination of Latin and
GreekAncient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek...
, meaning 'Chinese bird-lizard') is a
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
of
featheredThe realization that dinosaurs are closely related to birds raised the obvious possibility of feathered dinosaurs. Fossils of Archaeopteryx include well-preserved feathers, but it was not until the early 1990s that clearly nonavian dinosaur fossils were discovered with preserved feathers...
dromaeosaurid
dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
from the Lower
CretaceousThe Cretaceous , Latin language for "chalky", usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago . In the geologic timescale, the Cretaceous follows on the Jurassic period and is followed by the Paleogene period of the...
Period (late
BarremianThe Barremian is an age in the geologic timescale between 130.0 ± 1.5 Ma and 125.0 ± 1.0 Ma). It is a subdivision of the Early Cretaceous epoch...
) of the
Yixian FormationThe Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans 11 million years during the early Cretaceous period...
in what is now
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
. It caused a sensation because it was the fifth of the non - avian
feathered dinosaurThe realization that dinosaurs are closely related to birds raised the obvious possibility of feathered dinosaurs. Fossils of Archaeopteryx include well-preserved feathers, but it was not until the early 1990s that clearly nonavian dinosaur fossils were discovered with preserved feathers...
generaGenera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
discovered by 1999. It was collected from the Sihetun locality of western Liaoning. It was in Layer 6, lower (Chaomidianzi) Yixian Formation, Jehol Group.
The holotype specimen is IVPP V12811, in the collection of the
Institute of Vertebrate Paleontology and PaleoanthropologyThe Institute of Vertebrate Paleontology and Paleoanthropology of China is a prominent research institution and collections repository for fossils, including many dinosaur and pterosaur specimens . As its name suggests, research is focused on both paleontological topics and those relating to...
in
BeijingBeijing is a metropolis in northern China and the capital of the People's Republic of China...
,
ChinaChina is a cultural region, an ancient civilization, and, depending on perspective, a national or multinational entity extending over a large area in East Asia....
. Another specimen, NGMC - 91, is probably a juvenile
Sinornithosaurus. Qiang et al. (2001) were reluctant to name NGMC - 91 because, although the specimen is completely articulated, almost all of the bones shattered when the fossil slabs were split, so that only the silhouettes of theses bones are clear in most of the part and counterpart. This obscured diagnostic skeletal features, which made the specimen's genus uncertain. NGMC - 91, also called "Dave", is in the collection of the National Geological Museum of China. It was collected in Fanzhangzi quarry, near Lingyuan City, Liaoning Province, China. This is around 130 km from the Sihetun locality. A specimen of the fish
LycopteraLycoptera, Lycoptera davidi, was a fish that lived in the Late Jurassic 157 - 136 Ma mainly around present day China.-References:*...
is also preserved near the foot of NGMC - 91.
Xu Xing described
Sinornithosaurus and performed a phylogenetic analysis which demonstrates that it is basal, or primitive, among the dromaeosaurs.he has also demonstrated that features of the skull and shoulder are very similar to Archaeopteryx and other
AvialaeAvialae is a clade containing birds and their most immediate dinosaurian relatives.-Competing definitions:Systematic studies of the Avialae have produced different results depending on the specimens included and the definitions used. Including or excluding Archaeopteryx from the group Aves has a...
. Together these two facts demonstrate that the earliest dromaeosaurs were more like birds than the later dromaeosaurs were. This contradicts one argument made by critics of the theory that birds evolved from dinosaurs. See
Temporal paradox (paleontology)The temporal paradox, or time problem is a controversial issue in the evolutionary relationships of birds. It was described by paleornithologist Alan Feduccia.- Objection to consensus :The concept of a "temporal paradox" is based on the following facts...
.
Feathers
Both of the
Sinornithosaurus specimens above preserved impressions of feathers. They were composed of filaments, and showed two features that indicate they are early feathers. First, several filaments were joined together into "tufts", similar to the way down is structured. Second, a row of filaments (
barbs) were joined together to a main shaft (
rachis), making them similar in structure to normal
birdBirds are winged, bipedal, endothermic , vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the Bee Hummingbird to the ...
feathers. However, they do not have the secondary branching and tiny little hooks (
barbulesBarbules are a part of the tree formed by feathers : the trunk, or axis, being the rachis and the barbs the main boughs, barbules are the secondary branches.Barbules have minute hooks called barbicels for cross-attachment.-References:*...
) that modern feathers have, which allow the feathers of modern birds to form a discrete vane. In NGMC - 91 the feathers covered the entire body, including the head in front of the eye, the neck, wing - like sprays on the arms, long feathers on the thighs, and a lozenge - shaped fan on the tail like that of
ArchaeopteryxArchaeopteryx, sometimes referred to by its German name Urvogel , is the earliest and most primitive bird known...
.
Classification
Sinornithosaurus was a member of the family
DromaeosauridaeDromaeosauridae is a family of bird-like theropod dinosaurs. They were small to medium-sized, feathered carnivores that flourished in the Cretaceous Period. In informal usage they are often called "raptors" , a term popularized by the film Jurassic Park...
, a group of agile,
predatoryA carnivore , meaning 'meat eater' , is an animal that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of vertebrate and/or invertebrate animal tissue, whether through predation or scavenging...
dinosaurs with a distinctive sickle-shaped toe claw, which also includes
DeinonychusDeinonychus was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter long dinosaur lived during the early Cretaceous Period, about 115-108 million years ago...
and
UtahraptorUtahraptor is the largest known member of the theropod dinosaur family Dromaeosauridae, and dates from the upper Barremian stage of the Early Cretaceous period .-Discovery:...
. It lived about 125 million years ago in the Barremian
ageIn chronostratigraphy, a stage is a succession of rock strata laid down in an single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
of the Lower Cretaceous period, which makes it among the earliest and most primitive dromaeosaurids yet discovered. The presence of vaned feathers on
Sinornithosaurus is consistent with feather evidence from other Dromaeosaurs. see
MicroraptorMicroraptor is a genus of small, dromaeosaurid dinosaur. About two dozen well-preserved fossil specimens have been recovered from Liaoning, China...
,
VelociraptorVelociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 mya during the later part of the Cretaceous Period. Only two species are currently recognized, although others have been assigned in the past. The type species is V...
, and
RahonavisRahonavis is a genus of dinosaur from the Late Cretaceous of what is now northwestern Madagascar. It is known from a partial skeleton found in Maevarano Formation rocks at a quarry near Berivotra, Mahajanga Province.-Description:Rahonavis was a small predator, about the size of Archaeopteryx,...
. see also
feathered dinosaursThe realization that dinosaurs are closely related to birds raised the obvious possibility of feathered dinosaurs. Fossils of Archaeopteryx include well-preserved feathers, but it was not until the early 1990s that clearly nonavian dinosaur fossils were discovered with preserved feathers...
.
Sinornithosaurus is known from at least two species.
S. millenii ("millennium Chinese bird-lizard") is the
type speciesIn taxonomy, a type species is a technical phrase, involved in the application of formal names...
, described in 1999. A second species,
S. haoiana ("Hao's Chinese bird-lizard") was described by Liu
et al. in 2004 based on a new specimen which differed from
S. millenii in features of the skull and hips. An incredibly well-preserved microraptorian nicknamed "Dave" (specimen NGMC 91) may represent a third species of
Sinornithosaurus, or a juvenile.
Discovery
Sinornithosaurus was discovered by Xu Xing, Wang Xiaolin and Wu Xiaochun of the Institute of Vertebrate Paleontology and Paleoanthropology of
BeijingBeijing is a metropolis in northern China and the capital of the People's Republic of China...
. An almost-complete
fossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
with feather impressions, was recovered from Liaoning Province, China, in the
Yixian FormationThe Yixian Formation is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans 11 million years during the early Cretaceous period...
; the same incredibly rich location where four dinosaurs with feathers were discovered previously,
ProtarchaeopteryxProtarchaeopteryx is a genus of turkey-sized feathered theropod dinosaur from China.Well-developed, vaned feathers extended from the short, stubby tail; the hands were long and slender, and had three fingers with sharp, curved, claws. Its bones were hollow, and bird-like, and it possessed a wishbone...
,
SinosauropteryxSinosauropteryx is the first and most primitive genus of dinosaur found with the fossilized impressions of feathers. It lived in China during the early Cretaceous period and may have been a close relative of Compsognathus. It was the first dinosaur genus discovered from the famous Jehol Biota of...
,
CaudipteryxCaudipteryx is a genus of peacock-sized theropod dinosaurs that lived in the Aptian age of the early Cretaceous Period . They were feathered and remarkably birdlike in their overall appearance....
, and
BeipiaosaurusBeipiaosaurus is a genus of therizinosauroid theropod dinosaur. The discovery of Beipiaosaurus , which translates as "Beipiao lizard" after a city in China near the location of its discovery, was announced in the May 27, 1999, issue of the journal Nature...
.
External links