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.
Cetiosaurus
The first fossils, vertebrae and limb elements, were discovered near Chipping Norton in the early nineteenth century and were reported upon by collector John Kingdon in a letter read on 3 June 1825 to the Geological Society; they were seen as possibly belonging to a whale or crocodile. In 1841 biologist, comparative anatomist and palaeontologist Sir Richard Owen, named these as the genus "Cetiosaurus", the year before he coined the term Dinosauria. Owen initially did not recognise "Cetiosaurus" for a dinosaur but considered it a gigantic sea-dwelling reptile. This was reflected by the name, derived from Greek κήτειος, "kèteios", "sea-monster". In 1842 Owen named two species in the genus: "Cetiosaurus hypoolithicus" and "Cetiosaurus epioolithicus". The specific names reflected whether the finds had been made below (hypo) or above (epi) the so-called oolithic layers. The first species was based on the material of Kingdon; the latter on vertebrae and metacarpals found at White Nab in Yorkshire. The publication did not contain a sufficient description and the species are often considered "nomina nuda". The same year in a subsequent publication Owen named four additional "Cetiosaurus" species: "Cetiosaurus brevis", "the short one"; "Cetiosaurus brachyurus", "the short-tailed"; "Cetiosaurus medius", "the medium-sized", and "Cetiosaurus longus", "the long one". Owen had abandoned the two earlier names, as shown by the fact that their fossils were referred to several of the new species. These again were each mostly based on disparate material, from often geographically widely separated sites. As became apparent in 1849, some of these bones were not sauropod in nature at all but of Iguanodontidae. That year Alexander Melville, in a misguided attempt to clear matters up, named the authentic sauropod material of "C. brevis" as "Cetiosaurus conybeari" but thereby merely created a junior objective synonym of the former name.