English: Hesperonyx is an iguanodontian ornithopod dinosaur from the Late Jurassic of what is now Portugal. It was a stout bipedal herbivore, relatively small for an iguanodontian at about 3–4 m in length. Based on its arms, it appears to have lacked the ability to switch to quadrupedality seen in more derived members such as the hadrosaurs. Basal iguanodontians from Europe are rare, and the discovery of Hesperonyx is helpful in understanding their evolution and dispersal.