[D] Sinornithosaurus millenii [Su] [sG] [T]
Describer
Xu, Wang & Wu, 1999
Time
?Cretaceous Early
Classification
Saurischia Theropoda Tetanurae Coelurosauria Dromaeosauridae
Diet
Carnivore
Fossilsite
Yixian Formation, Liaoning province, China
Info
Genus - Typespecies - Skull
Holotype (and only specimen)
IVPP V12811
Sinornithosaurus not only greatly increases our knowledge of Dromaeosauridae but also provides evidence for a filamentous integument in this group. It is remarkably similar to early birds postcranially. The shoulder girdle shows that terrestrial dromaeosaurids had attained the prerequisites for powered, flapping flight, supporting the idea that bird flight originated from the ground up.
Sinornithosaurus millenii represents the fifth non-avialean theropod genus recovered from this locale which features a filamentous integument. Nowhere else in the world have non-avialean theropod specimens been found which unambiguously preserve these elusive details.
Distinctive cranial characteristics of Sinornithosaurus millenii include the presence of a deep excavation on the posteroventral margin of the premaxilla, a diastema between the premaxillary and maxillary teeth, a number of pits and ridges on the anterolateral surface of the antorbital fossa, long posterolateral process of the parietal that are sharply posteriorly directed, the column-like margin of the pterygoid process of the quadrate, the bifurcated posterior end of the dentary, and a distinctive groove posterior to the anterior carina on the lingual surface of the premaxillary tooth crowns.
The study on the skull of Sinornithosaurus millenii [Xu, X. and Wu, X.-C. (2001) provides new information on the poorly known cranial anatomy of dromaeosaurid dinosaurs, revealing that dromaeosaurids share more similarities with Archaeopteryx than previously thought. It also provides evidence suggesting that early dromaeosaurids are more bird-like than the later, more derived ones, thus contradicting claims that more bird-like dinosaurs appeared later in fossil record than the earliest birds.
Xu, Wang & Wu, 1999
Time
?Cretaceous Early
Classification
Saurischia Theropoda Tetanurae Coelurosauria Dromaeosauridae
Diet
Carnivore
Fossilsite
Yixian Formation, Liaoning province, China
Info
Genus - Typespecies - Skull
Holotype (and only specimen)
IVPP V12811
Sinornithosaurus not only greatly increases our knowledge of Dromaeosauridae but also provides evidence for a filamentous integument in this group. It is remarkably similar to early birds postcranially. The shoulder girdle shows that terrestrial dromaeosaurids had attained the prerequisites for powered, flapping flight, supporting the idea that bird flight originated from the ground up.
Sinornithosaurus millenii represents the fifth non-avialean theropod genus recovered from this locale which features a filamentous integument. Nowhere else in the world have non-avialean theropod specimens been found which unambiguously preserve these elusive details.
Distinctive cranial characteristics of Sinornithosaurus millenii include the presence of a deep excavation on the posteroventral margin of the premaxilla, a diastema between the premaxillary and maxillary teeth, a number of pits and ridges on the anterolateral surface of the antorbital fossa, long posterolateral process of the parietal that are sharply posteriorly directed, the column-like margin of the pterygoid process of the quadrate, the bifurcated posterior end of the dentary, and a distinctive groove posterior to the anterior carina on the lingual surface of the premaxillary tooth crowns.
The study on the skull of Sinornithosaurus millenii [Xu, X. and Wu, X.-C. (2001) provides new information on the poorly known cranial anatomy of dromaeosaurid dinosaurs, revealing that dromaeosaurids share more similarities with Archaeopteryx than previously thought. It also provides evidence suggesting that early dromaeosaurids are more bird-like than the later, more derived ones, thus contradicting claims that more bird-like dinosaurs appeared later in fossil record than the earliest birds.