Where Romania is now, there was once an island of dwarf dinosaurs

Sea covered most of the continent. The land where Transylvania lies today stood above the water at about 27–28° north, roughly the latitude of today's Canary Islands, at least 200–300 kilometres from the nearest shore.

How big was the island? The working estimate is about 80,000 km², roughly the size of Hispaniola, the island shared by Haiti and the Dominican Republic. Other reconstructions go up to 200,000 km². The climate was subtropical, with a rainy and a dry season and an average temperature of 20–25 °C.

On an island, food and room are scarce. Over many generations large animals often end up smaller than their mainland relatives: it happened, much later, to the elephants and hippos of the Mediterranean. In 1912, in Vienna, Franz Nopcsa said the same had happened to the dinosaurs of Transylvania. He had noticed that the turtles and crocodiles here reached their normal size while the dinosaurs almost always stayed below it.

The dinosaurs had company. Among them lived the crocodile Allodaposuchus, the turtle Kallokibotion, frogs, lizards, a snake found at Tuștea, and a family of small mammals that, in the Cretaceous, lived only here: the kogaionids. One of them, Barbatodon, had teeth reddened by iron in the enamel. Another, Litovoi, had one of the smallest brains for its body size known in any mammal.

Pick a dinosaur, set your height and look. Then bring in a relative.

Four of these five animals are smaller than their relatives elsewhere in the world. For Magyarosaurus the proof that it was adult comes from the bone, and you can see it below; researchers reached the same conclusion for Telmatosaurus. For Zalmoxes and Struthiosaurus some researchers think otherwise: that their ancestors were already small and the island merely kept them that way.

The fifth breaks the rule. Uriash kadici, named in 2025, weighed 5–8 tonnes. Its name comes from the giants of Romanian fairy tales. So the island had large titanosaurs too. A few big bones, which had led some to think the small bones belonged to youngsters, have been assigned to it.

Hatzegopteryx, “the Hațeg wing”, was a pterosaur: a relative of the dinosaurs without being one of them. Scroll and let its wings open.

Its wingspan is estimated at 10–12 metres. The jaw alone was half a metre wide, and the whole skull between one and a half and two metres long. The first bones came out at Vălioara and were described in 2002.

No large meat-eating dinosaur has been found on the island. The place of the big hunter stood empty, and two researchers, Darren Naish and Mark Witton, think Hatzegopteryx filled it. They studied a huge neck vertebra found at Râpa Roșie, near Sebeș: it is short and very robust, fit for a short, powerful neck. Arambourgiania, another giant pterosaur, had a long, thin neck.

It is a hypothesis resting on a few bones. No complete Hatzegopteryx skeleton has been found, and the wingspan is worked out by comparison with better-known relatives. That is why you will meet 10, 11 or 12 metres, depending on who did the sum.

In September 2009 Mátyás Vremir pulled from the red clay at Sebeș Glod, two and a half kilometres from the town of Sebeș, half a skeleton unlike anything seen before.

The researchers who described it in 2010 chose the name: balaur, the old Romanian word for dragon, and bondoc, meaning stocky. Its hand bones were fused and its build was stocky. The first toe, small in other dinosaurs of its kind, had grown almost as large as the second and carried a big claw of its own. How long the whole animal was, the studies do not say: the skeleton is incomplete.

There are two views on what kind of animal it was. Read them in turn.

For a long time the objection was that the small Hațeg bones might belong to youngsters. A fine saw and a microscope settle it.

The study has a limit, and the authors state it: the classic sign that growth has stopped, a thin dense layer at the edge of the bone, appears in none of the specimens. The conclusion rests on how thoroughly the bone had been rebuilt.

The large bone used for comparison, which had led some to think Magyarosaurus grew much bigger, was assigned in 2025 to another animal: Uriash kadici.

The Nopcsa family had their castle at Săcel and land at Sânpetru. In 1895 Ilona, the younger sister, found a few fossil bones there. Franz was 17 or 18.

Your turn to dig

Under the layer of clay is the skull Franz found in 1895, as it appears in his 1900 paper. Rub the clay away until it shows.

After Nopcsa, who died in 1933, research stopped for more than four decades. It was restarted in 1977 by Dan Grigorescu of the University of Bucharest, with a small group of students, again in the Sibișel valley. Pui, Vălioara and Tuștea followed.

Tuștea has left a question unanswered. The eggshell is of the type that, everywhere else in the world, titanosaurs lay. Yet the hatchlings found among the eggs are certainly hadrosauroid, and the hadrosauroid known from the island is Telmatosaurus. Who laid the eggs?

Eight statements about the island. Some sound like fairy tales and are true.

The area has been a UNESCO geopark since 2015, run by the University of Bucharest. It has several visitor houses, each with its own subject.

• House of the Dwarf Dinosaurs, Sânpetru Opened in 2013. It has a reconstructed dig site and is the start of the 10-kilometre “Dinosaur Valley” trail along the Sibișel.
• Geopark House, Hațeg At 9A Libertății Street, with the permanent exhibition “Balauri, dragoni, dinozauri”, opened in 2014.
• House of Science and Art, General Berthelot In front of it stands a life-size Magyarosaurus rearing on its hind legs, by the Canadian sculptor Brian Cooley. A Tuștea nest is on display inside. The statue was made before the 2025 revision, which puts Magyarosaurus under 3 metres.
• House of Volcanoes, Densuș Opened in 2014.

Opening hours and prices change with the season; check them on the geopark's website before you travel. The site of the Tuștea nests is now abandoned and overgrown.