Eolambia

Eolambia (meaning "dawn lambeosaurine") is a genus of herbivorous hadrosauroid dinosaur from the early Late Cretaceous of the United States. It contains a single species, E. caroljonesa, named by paleontologist James Kirkland in 1998. The type specimen of Eolambia was discovered by Carole and Ramal Jones in 1993; the species name honors Carole. Since then, hundreds of bones have been discovered from both adults and juveniles, representing nearly every element of the skeleton. All of the specimens have thus far been found in Emery County, Utah, in a layer of rock known as the Mussentuchit Member of the Cedar Mountain Formation.

Measuring up to long, Eolambia is a large member of its group. While it closely approaches the Asian hadrosauroids Equijubus, Probactrosaurus, and Choyrodon, in traits of the skull, vertebrae, and limbs, it may actually be more closely related to the North American Protohadros. This grouping, based on the straightness of the quadrate bone and scapula, would represent an isolated, endemic radiation of hadrosauroids. Despite resembling hadrosaurids – lambeosaurine hadrosaurids in particular – in several features, leading to its initial identification as one of them, these similarities have been rejected as either entirely convergent or misinterpreted.