What is "notohypsilophodon"

Notohypsilophodon (meaning "southern Hypsilophodon") is a genus of euornithopod dinosaur from the Upper Cretaceous of Argentina. It was described as the only " hypsilophodont" known from South America, although this assessment is not universally supported, and Gasparinisaura is now believed to have been a basal euornithopod as well.