Secernosaurus

Secernosaurus (meaning "severed lizard") is a genus of herbivorous hadrosaurid dinosaur that lived during the Late Cretaceous of what is now Argentina. This genus and its close relatives lived in South America, unlike most hadrosaurids, which lived in the Laurasian continents of Eurasia and North America. It has been suggested that the ancestors of Secernosaurus crossed into South America when a land bridge temporarily formed between North and South America during the Late Cretaceous and allowed biotic interchange between the two continents.

==History of research== The holotype of Secernosaurus koeneri was collected in 1923 as part of an expedition by the Field Museum led by J. B. Abbott. However, the specimen was not studied until the 1970s. In 1979, Brett-Surman named Secernosaurus. Though hadrosaurid specimens from South America had been described before, Secernosaurus koeneri was the first species of South American hadrosaurid to be formally named. The genus name Secernosaurus means "separated reptile" and comes from the Latin verb sēcernō, meaning to sever or divide, in reference to its geographic location separated from Laurasian hadrosaurs. The species name S. koerneri honors Harold E. Koerner. The holotype of Secernosaurus koerneri is FMNH P13423, a partial skeleton from the Lago Colhué Huapi Formation of Chubut province, Argentina.