Adelolophus

Adelolophus (meaning "unknown crest") is a genus of lambeosaurine dinosaur (a crested "duck-bill") from Upper Cretaceous rocks in the U.S. state of Utah. The type and only known species is A. hutchisoni; the type specimen consists only of a broken . It constitutes the oldest known lambeosaur remains from North America, as well as the only known lambeosaur species from the Wahweap Formation, of which it pertains to the Upper Member. Among its relatives, it seems to be particularly similar to Parasaurolophus, rather than animals like Lambeosaurus; phylogenetic analysis confirms this, finding it in Parasaurolophini (tube-headed lambeosaurs). It would have lived in a wet environment, bordering on the sea but with a more arid season during some times of the year. This environment would have been shared with a diverse variety of fish and turtles, as well as other dinosaurs like ceratopsids and tyrannosaurids.

==Discovery and naming== thumb|left|Adelolophus was discovered in the badlands of the Grand Staircase–Escalante National Monument|Grand Staircase A fossil bearing locality near Death Ridge in Kane County, Utah was first reported in 1973 by Howard D. Zeller; this locality is part of the Wahweap Formation, found within the Grand Staircase–Escalante National Monument area. The information reported by Zeller would be used by John Howard Hutchison and colleagues to return there to collect fossils in 1999. Among these was the (a jawbone) of a lambeosaurine hadrosaur. This maxilla was first reported in 2013, in a paper by Terry Gates and colleagues. It was noted as the only known lambeosaur material from the formation (reported as being from the Upper Member), and the oldest known lambeosaur material in North America. They suggested the unique morphology indicated it was a new taxon, but refrained from naming it.