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.
Nyasasaurus
"Nyasasaurus" is likely either a basal dinosaur or close to Dinosauria. Other phylogenetic analyses have indicated that the sister group to Dinosauria is a family of herbivorous dinosauriforms called Silesauridae. The fossil record of silesaurids dates back to the late Anisian (the silesaurid "Asilisaurus" is also known from the Manda Formation), suggesting that the first dinosaurs also appeared around this time. Before "Nyasasaurus" was recognized as a possible dinosaur, a long ghost lineage of approximately 16 million years existed between the earliest dinosaurs and earliest silesaurids.