Haţeg Island

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 Adriatic Plate's northwest movement across the Piemont-Liguria Ocean towards the end of the Cretaceous. There is no real present-day analog, but overall, the island of Hainan (off the coast of China) 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.

The Hungarian paleontologist Franz Nopcsa theorized that "limited resources" found on the island commonly have an effect of "reducing the size of animals" over the generations, producing a localized form of dwarfism. Nopcsa's theory of insular dwarfism — also known as the island rule — is today widely accepted.

While a variety of estimates regarding the prehistoric island's size have been given over the years, the most reliable estimate places it at roughly 80,000 square kilometers during the Maastrichtian, or about the size of the modern island of Hispaniola. It was positioned just within the equatorial belt, at about 27°N latitude.

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