Confuciusornithidae

Confuciusornithids Temporal range: Early Cretaceous, 131–120 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil specimen of Confuciusornis sanctus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Clade:	Avialae
Clade:	Pygostylia
Clade:	†Confuciusornithiformes Hou et al., 1995
Family:	†Confuciusornithidae Hou et al., 1995
Type species
†Confuciusornis sanctus Hou et al., 1995
Genera
†Changchengornis †Confuciusornis †Eoconfuciusornis †Evgenavis? †Yangavis †"Proornis"? †Zhongornis?

Confuciusornithidae is an extinct family of pygostylian avialans known from the Early Cretaceous, found in northern China. They are commonly placed as a sister group to Ornithothoraces, a group that contains all extant birds along with their closest extinct relatives. Confuciusornithidae contains four genera, possessing both shafted and non-shafted (downy) feathers. Some specimens probably referable to this clade represents one of the earliest known fossil evidence of primary feather moulting.^[1] They are also noted for their distinctive pair of ribbon-like tail feathers of disputed function.

The wing anatomy of confuciusornithids suggests an unusual flight behavior, due to anatomy that implies conflicting abilities. They possessed feathers similar to those of fast-flapping birds, which rely on quick flapping of their wings to stay aloft. At the same time, their wing anatomy also suggests a lack of flapping ability. Confuciusornithids are also noted for their beak and lack of teeth, similar to modern birds. Both predators and prey, confuciusornithid fossils have been observed with fish remains in their digestive systems and have themselves been found in the abdominal cavities of Sinocalliopteryx, a compsognathid predator.