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.
Tyrannosaurus
Sue Hendrickson, an amateur paleontologist, discovered the most complete (approximately 85%) and largest "Tyrannosaurus" skeleton in the Hell Creek Formation on August 12, 1990. The specimen Sue, named after the discoverer, was the object of a legal battle over its ownership. In 1997, the litigation was settled in favor of Maurice Williams, the original land owner. The fossil collection was purchased by the Field Museum of Natural History at auction for $7.6 million, making it the most expensive dinosaur skeleton to date. From 1998 to 1999, Field Museum of Natural History staff spent over 25,000 hours taking the rock off the bones. The bones were then shipped to New Jersey where the mount was constructed, then shipped with the bones back to Chicago for the final assembly. The mounted skeleton opened to the public on May 17, 2000 in the Field Museum of Natural History. A study of this specimen's fossilized bones showed that Sue reached full size at age 19 and died at age 28 years, the longest estimated life of any tyrannosaur known.