Elopteryx is a genus of, perhaps troodontid, maniraptoran theropod dinosaur based on fragmentary fossils found in late Cretaceous Period rocks of Romania. The single species, Elopteryx nopcsai, is known only from very incomplete material, and therefore is considered a nomen dubium by most paleontologists.

Hațeg Island was a large offshore island in the Tethys Sea which existed during the Late Cretaceous period, probably from the Cenomanian to the Maastrichtian ages. It was situated in an area corresponding to the region around modern-day Hațeg, Hunedoara County, Romania. Maastrichtian fossils of small-sized dinosaurs have been found in the island's rocks. It was formed mainly by tectonic uplift during the early Alpine orogeny, caused by the collision of the African and Eurasian plates towards the end of the Cretaceous. There is no real present-day analog, but overall, the island of Hainan is perhaps closest as regards climate, geology and topography, though still not a particularly good match. The vegetation, for example, was of course entirely distinct from today, as was the fauna.