Sinosauropteryx
Three specimens have been assigned to "Sinosauropteryx prima": the holotype GMV 2123 (and its counter slab [opposite face], NIGP 127586), NIGP 127587, and D 2141. Another specimen, IVPP V14202, was assigned to the genus but not to the only species by Zhang and colleagues. The assignment of an additional larger specimen to "S. prima", GMV 2124, was later found to be in error. All of the fossils were found in the Jianshangou or Dawangzhangzi Beds of the Yixian Formation in the Beipiao and Lingyuan regions of Liaoning, China. These fossil beds have been dated to 124.6–122 million years ago, during the early Aptian stage of the Early Cretaceous.
Daliansaurus
The Liaoning region of northeastern China has been one of the most productive fossil sites for understanding the evolution of feathered dinosaurs, including birds. All of the sinovenatorines - "Sinovenator", "Sinusonasus", "Mei", and "Daliansaurus" - lived in the Lujiatun Beds of the Yixian Formation. Rather than strict coexistence, it is possible that they replaced each other over time, or were geographically and ecologically segregated. Shen and colleagues identified the sinovenatorines as a localized radiation of troodontids confined to Liaoning during the Early Cretaceous; a similar radiation occurred with the many microraptorine dromaeosaurids which lived at roughly the same place and time. Sinovenatorines also paralleled dromaeosaurids in the minute but taxonomically informative anatomical differences between different members of the group. However, it is possible that some of these differences may arise from individual or ontogenetic variation.