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Description
A basal member of Dromaeosauridae , Sinornithosaurus was a tiny feathered dinosaur that lived in the early Cretaceous of what is now China. It was one of the first dinosaurs found with direct evidence of feathers. Although it was covered in feathers and hair-like filaments and had large wings, it is believed that it wouldn't have been capable of sustained, powered flight. The feathers on its arms lacked the structure of flying bird primaries and secondaries that keep them strong and able to repair themselves from the stresses of flight, and they also don't have the chest muscular for the degree of flapping necessary for flying. That said, it is believed that they would have been capable climbers and gliders, perhaps swooping down onto prey from branches above.

In 2009, a team of researchers presented evidence that Sinornithosaurus possessed a venomous bite. Later analysis of the features refuted this claim: the 'venom glands' and fang-like teeth were the results of poor preservation and misinterpretation and the grooves on the teeth are found in plenty of non-venomous animals. Despite the fact that even the authors of the paper have backed down on the claim, Sinornithosaurus is still frequently mentioned as a venomous dinosaur when it is mentioned in popular media.

This reconstruction shows an adult and a juvenile Sinornithosaurus. The juvenile is based on 'Dave', a famous fossil covered in preserved filaments. 'Dave' has often been listed as a juvenile Sinornithosaurus, with their anatomical differences from adults described as an example of dromaeosaur ontogeny (different anatomy depending on growth stages). There is a general consensus that 'Dave' is a juvenile Sinornithosaurus, so that is the direction I took with this reconstruction.

Another important thing to discuss about Sinornithosaurus is that studies of their fossil feathers and downy filaments have shown evidence of coloration! A range of reddish-browns, yellows, grey, and bands of black were discovered. As I could not find the exact patterning of these colors, this depiction is my best guess, not necessarily how it would have looked in life.

Cheers, folks!

-Keenan

Skeletal reference: Sinornithosaurus growth stages
Zhang et al (Coloration paper) oro.open.ac.uk/22432/2/4106469…

Description
A basal member of Dromaeosauridae , Sinornithosaurus was a tiny feathered dinosaur that lived in the early Cretaceous of what is now China. It was one of the first dinosaurs found with direct evidence of feathers. Although it was covered in feathers and hair-like filaments and had large wings, it is believed that it wouldn't have been capable of sustained, powered flight. The feathers on its arms lacked the structure of flying bird primaries and secondaries that keep them strong and able to repair themselves from the stresses of flight, and they also don't have the chest muscular for the degree of flapping necessary for flying. That said, it is believed that they would have been capable climbers and gliders, perhaps swooping down onto prey from branches above.

In 2009, a team of researchers presented evidence that Sinornithosaurus possessed a venomous bite. Later analysis of the features refuted this claim: the 'venom glands' and fang-like teeth were the results of poor preservation and misinterpretation and the grooves on the teeth are found in plenty of non-venomous animals. Despite the fact that even the authors of the paper have backed down on the claim, Sinornithosaurus is still frequently mentioned as a venomous dinosaur when it is mentioned in popular media.

This reconstruction shows an adult and a juvenile Sinornithosaurus. The juvenile is based on 'Dave', a famous fossil covered in preserved filaments. 'Dave' has often been listed as a juvenile Sinornithosaurus, with their anatomical differences from adults described as an example of dromaeosaur ontogeny (different anatomy depending on growth stages). There is a general consensus that 'Dave' is a juvenile Sinornithosaurus, so that is the direction I took with this reconstruction.

Another important thing to discuss about Sinornithosaurus is that studies of their fossil feathers and downy filaments have shown evidence of coloration! A range of reddish-browns, yellows, grey, and bands of black were discovered. As I could not find the exact patterning of these colors, this depiction is my best guess, not necessarily how it would have looked in life.

Cheers, folks!

-Keenan

Skeletal reference: Sinornithosaurus growth stages
Zhang et al (Coloration paper) oro.open.ac.uk/22432/2/4106469…