Drawing of Eolambia caroljonesa (reconstruction )

  • Utah, USA ( Cedar Mountain Formation)
  • Eolambia caroljonesa

Eolambia is a genus ornithopoder dinosaur from the group of Hadrosauroidea.

To date, several fragmentary skeletons of adults and juveniles are known; further embryonic remnants and possible eggshells could be described. All remains are from the Cedar Mountain Formation, a rich fossil deposit in the State of Utah, and to the early Cretaceous dated (early Cenomanian, before about 100 to 96 million years ago).

The only known species is Eolambia caroljonesa; Species and genus were described in 1998 by James I. Kirkland first time scientifically.


So far, three incomplete skulls are known, suggesting a skull length of up to one meter. Unlike the Lambeosaurinen nose and Zwischenkieferbein did not form bone crest. On each side of the upper jaw there were 32 dental trays while it each were probably less than 30 in the lower jaw at the holotype specimen. Under each "active" tooth were at least two replacement teeth at least in the lower jaw. The tooth crowns are characterized by a single central cutting edge and were the largest teeth 3.3 cm high and 1.7 cm wide. The rest of the skeleton ( Postkranium ) is characterized among other things by at least seven sacral vertebrae as well as high eddy thorns on the anterior caudal vertebrae. The forelimbs were compared with those of other genera massive and long.


Initially described James Kirkland Eolambia as a representative of the Lambeosaurinae, a subfamily within the Hadrosauridae, which is characterized by prominent head crests. Kirkland explained his association with various common features ( synapomorphies ), which in particular can be found at Zwischenkieferbein. Later authors classified Eolambia but outside the Hadrosauridae as representative of the original Hadrosauroidea. In a study published in 2001 reexamination of Eolambia fossils was found that there was indeed misinterpretations in many of the established Kirkland Lambeosaurinen - similar characteristics. This study looks Eolambia as close relatives of Probactrosaurus.

Research History and naming

1993 Carole and Ramal Jones discovered in the northwestern San Rafael Swell (east of Castle Dale, Utah) highly weathered fossil bones. They handed the fossils Donald Burge, director of the Prehistoric Museum in Price, which then organized an excavation that brought a fragmentary skeleton including skull -a-days. The skeleton lay just below the ground surface, which is why many bones were damaged by roots. Nearby is the skeleton of a new Nodosauriden genus was found. The site belongs to the Mussentuchit Members, a layer member of the Cedar Mountain Formation, and is today in honor of the discoverer as " Carol Site" known.

The scientific work of the new dinosaur took over the paleontologist James Kirkland. Kirkland examined more skeletons from the same excavation site, which were previously undescribed kept in the collection of the Oklahoma Museum of Natural History, and noticed that they can also be assigned to this genus. Kirkland named the new genus and species Eolambia caroljonesa. The genus name Eolambia means as much as " formerly Lambeosaurier " and underlines the very early appearance of this Kirkland of the subfamily Lambeosaurinae ascribed dinosaur. The second part of the species name, caroljonesa honors Carole Jones, who has discovered the reference to the type specimen.

Prior to his scientific description of the genus was the informal name " Eohadrosaurus ".


Further Reading

  • James Ian Kirkland: A new hadrosaurid from the upper Cedar Mountain Formation ( Albian - Cenomanian: Cretaceous ) of eastern Utah - the oldest known hadrosaurid ( Lambeosaurine? ). In: SG Lucas, JI Kirkland & JW Estep (eds.): Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin, 14, pp. 283-295, 1998
  • Jason J. Head: A reassessment of the phylogenetic status of Eolambia caroljonesa ( Ornithischia: Iguanodontia ), with comments on the North American iguanodontian record. Journal of Vertebrate Paleontology, 19, supplement to 3, 50 A, 1999
  • Jason J. Head: A reanalysis of the phylogenetic position of Eolambia caroljonesa ( Dinosauria, Iguanodontia ). Journal of Vertebrate Paleontology, 21, 2, pp. 392-396, 2001