page_title: Sinornis
section_title: Flight and perching
hierarchical_section_title: Sinornis / Description / Flight and perching
caption_attribution_description: Sinornis.
context_page_description: Sinornis is a genus of enantiornithean birds from the Lower Cretaceous Jiufotang Formation of the People's Republic of China.
  When it was described in 1992, this 120 million-year-old sparrow-sized skeleton represented a new avian sharing "primitive" features with Archaeopteryx as well as showing traits of modern birds. Its basal features include, but are not limited to, a flexible manus with unguals, a footed pubis, and stomach ribs. Sinornis is known only from the type species, Sinornis santensis. The generic name comes from the Latin Sino~, 'China' and the Greek ornis, 'bird'. The specific name santensis refers to the provenance from Chaoyang county in Liaoning Province as Santa, meaning "Three Temples", is a traditional name of the county.
context_section_description: Derived bird traits in the skeleton of Sinornis are typically flight or perching adaptations. At a time when very few intermediary forms were known, the fossil seemed to provide an early glimpse of flight evolution, showing the intermediate evolutionary step between the "primitive" wings of Archaeopteryx to specialized wings of modern birds. As in modern birds, Sinornis had a modified wrist bone, with a groove that lets the wrist bend sharply back, tightly tucking the wings during flight or rest. Sinornis was capable of flight similar to modern birds based on breastbone and shoulder structures that provided both room and support for bulky aerobic flight muscles. It also had reduced claws and small hands with a stable second finger that anchored important flight feathers. Unlike the fused finger bones of modern birds, Sinornis had separate finger bones that were well adapted for flight, while the reduction of the tail moved the centre of gravity forwards.  Sinornis was also capable of perching and climbing.
caption: Restoration of Sinornis perching
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