The Yixian Formation is a geological formation in Liaoning, People's Republic of China, that stems from the early Cretaceous period. It is known for its fossils. It was initially recognized during the time the Japanese Empire controlled a large chunk of Manchuria (Northern China) called "Jehol". During the occupation of Jehol, many Japanese scientists had noticed fossil remains of extinct fish and reptiles, possibly the champsosaurs. These initial fossil discoveries made by Japanese scientists vanished from history once World War II ended in 1945. By 1949, when administration of the area passed to the Communist Party and its leader Mao Tse-Tung, the fossils of Yixian were studied only by Chinese scientists. It was not until the 1990s when remarkable fossils of birds and dinosaurs were excavated. Since 1996, a number of dinosaur fossils that have revolutionized our knowledge of these animals have been found at Yixian; among them are the first known non-avian theropods with feathers.
Fossils found at Yixian include:
Dinosaurs
- Sinosauropteryx, the first dinosaur found here
- Protarchaeopteryx
- Caudipteryx
- Psittacosaurus
- Sinornithosaurus
- Beipiaosaurus
- Dilong
- Mei long, a small dinosaur that has been fossilized in a sleeping position, with its head under a wing
- Jinzhousaurus
- Sinovenator
- Liaoceratops
- Incisivosaurus
- Scansoriopteryx
- Microraptor
- Shenzhousaurus
- Jeholosaurus
- Huaxiagnathus
- Liaoningosaurus
Birds
- Cathayornis
- Jeholornis
- Sapeornis
- Confuciusornis
- Liaoxiornis
- Liaoningornis
- Longipteryx
Mammals
- Repenomamus, an early mammal
- Jeholodens
- Eomaia
- Sinodelphys
- Maotherium
- Sinobaatar
- Zhangheotherium
- Akidolestes
Reptiles
Pterosaurs
- Sinopterus
- Haopterus
- Jeholopterus
- Eosipterus
- Beipiaopterus
- Boreopterus
- Feilongus
Others
- Manchurochelys, a turtle
- Hyphalosaurus
- Monjorosuchus
- Dalinghosaurus, a lizard
- Yabeinosaurus, a lizard related to geckos and skinks
Amphibians
- Jeholotriton, a gilled salamander
- Callobatrachus, a frog
- Mesophyrne, a frog with clawed toes
Fish
- Peipiaosteus, a fish related to sturgeons
- Lycoptera, herring-like fish
- Sinamia
- Mesomyzon mengae, a fossil lamprey
Insects and other Arthropods
- giant water strider bug
- Jehol crayfish
- Orb-weaving spider
- Mayfly
- Carrion-eating beetles
- Cicada
- Dragonfly
- Cockroach
- Palaepangonius, an early pollinating fly
Plants
- Archaefructus
- Horsetail
- Ephedra
- Conifer trees
- Ginkgo trees
- Archaeamphora, the earliest known carnivorous plant