Jehol Biota

The Jehol biota ^[1] includes all the living organisms – the ecosystem – of northeastern China between 133 to 120 million years ago (mya). This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation, some 125–121 mya,^[2] and the Jiufotang Formation. It is also believed to have left fossils in the Sinuiju series of North Korea.^[3]

The ecosystem in the Lower Cretaceous was dominated by wetlands and numerous lakes (not rivers, deltas, or marine habitats). Rainfall was seasonal, alternating between semi-arid, and mesic conditions.^[4] The climate was temperate. The Jehol ecosystem was interrupted at times by ash eruptions from volcanoes to the west.^[5] The word Jehol was the name given during the Japanese occupation of North-East China, 1933–1946.

The Jehol biota is noteworthy for the many different fossils and the large numbers of individuals of each species that have been recovered.

1. ↑ Chinese: 热河群; pinyin: rè hé qún
2. ↑ Swisher, Carl C. et al. 1999. "Cretaceous age for the feathered dinosaurs of Liaoning, China". Nature 400:58–61
3. ↑ Li, Quanguo & Gao, Ke-qin 2007. Lower Cretaceous vertebrate fauna from the Sinuiju basin, North Korea as evidence of geographic extension of the Jehol Biota into the Korean Peninsula. Journal of Vertebrate Paleontology 27, supplement to number (3). pp106A
4. ↑ Semi-arid: receives low annual precipitation. Mesic: a type of habitat with a moderate or well-balanced supply of moisture, i.e. a mesic forest, a temperate hardwood forest, or dry-mesic prairie.
5. ↑ Zhonghe, Zhou; Barrett, Paul M. & Hilton, Jason. 2003. An exceptionally preserved Lower Cretaceous ecosystem Nature 421:807–811.