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

A fully grown long-necked dinosaur there weighed less than a tonne. Above them flew a reptile whose wings measured 10–12 metres from tip to tip. Stand next to them, to scale, and see where their bones came out of the ground.

By Marius Comper · 19 September 2026 · every measurement comes from a published study, linked under [sources](#surse)

## The descent through time, from today to 70 million years ago

- **Today** The village of Sânpetru, Hunedoara county, Romania, in the valley of the Sibișel stream. Bones come out of the valley sides.
- **131 years ago** In 1895 Ilona Nopcsa finds the first fossil bones here, on the family estate. Her brother Franz, still at school, starts searching too.
- **66 million years ago** The Cretaceous ends and the dinosaurs that did not fly disappear. In the rocks of Transylvania their fossils stay abundant and varied until at least a million years before the end.
- **70 million years ago** Layers of volcanic ash in the north-west of Hațeg Country have been dated to 69.8 and 71.3 million years. The place was then on an island.

## Europe was an archipelago, and Hațeg was one of its islands

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.

## How small were they, really?

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

### *Magyarosaurus dacus* — dwarf sauropod (long-necked dinosaur)

The smallest adult sauropod known. Its close relatives are among the heaviest animals ever to walk on land.

- Length: 2.2–2.8 m (2025 study); older estimates said 6 m
- Weight: 660–970 kg, like a heavy horse
- Food: plants
- Found at: Hațeg Basin
- Named: 1915 by Nopcsa as Titanosaurus; Magyarosaurus since 1932

### *Telmatosaurus transsylvanicus* — hadrosauroid, a relative of the duck-billed dinosaurs

A dinosaur with a broad beak and rows of small teeth for grinding plants. Its mainland relatives were twice as long.

- Length: about 4 m
- Food: plants
- Found at: Sânpetru; Franz Nopcsa found the skull in 1895
- Named: 1900 as Limnosaurus; renamed Telmatosaurus in 1903
- Worth knowing: one Telmatosaurus jaw carries the first ameloblastoma, a benign tumour, known in a fossil

### *Zalmoxes robustus* — stocky plant-eater

Short, sturdy, beaked. The genus's second species, *Z. shqiperorum*, was reclassified in 2026 as an early relative of Triceratops, under the name *Ferenceratops*.

- Length: up to 3 m
- Food: plants
- Found at: Hațeg Basin, the Sebeș area, Rusca Montană
- Named: described by Nopcsa in 1902 as Mochlodon; Zalmoxes since 2003
- Worth knowing: the Paleobiology Database records more fossils of it than of any other dinosaur in Romania

### *Struthiosaurus transylvanicus* — armoured dinosaur

A small plant-eater protected by an armour of bony plates.

- Length: 2–2.5 m, estimated from Hungarian specimens of the same genus
- Food: plants
- Found at: Hațeg Basin
- Named: Struthiosaurus transylvanicus, Nopcsa, 1915

### *Uriash kadici* — large titanosaur (a sauropod)

Proof that not every dinosaur on the island was a dwarf.

- Length: 8.8–11.9 m
- Weight: 5–8 tonnes
- Food: plants
- Found at: Vălioara, Hațeg Basin
- Named: 2025; kadici honours the geologist Ottokár Kadić, who collected the bones

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.

## The island's largest flier had wings 10–12 metres across

*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.

## Two sickle claws on each foot, and a dispute still open

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.

### Velociraptor's stocky cousin

The describers placed it beside *Velociraptor*, in the dromaeosaurid family. The two pairs of claws would have served to grasp or slash prey. On this reading *Balaur* was the island's small predator.

It was not a dwarf. Its closest relatives, from Asia and North America, were about the same size.

### A bird that no longer flew

In 2015 Andrea Cau, Tom Brougham and Darren Naish reran the analysis and found it closer to living birds than *Archaeopteryx* is. The fused hand would be a reduced wing. Its food? Plants, or a bit of everything, they say; not a predator.

The authors concede the raptor option cannot be ruled out either. A 2021 paper co-written by one of the describers still calls it a predator. The dispute is open.

## Giant's baby or adult dwarf? The answer is in the bone

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

**Here are two slices of bone, drawn as diagrams. Which one looks like Magyarosaurus bone?**

A: many wide channels for blood vessels, the sign of fast-growing bone. B: small, crowded rings, the traces of bone that has been rebuilt many times.

Slice B. Young bone grows fast and is threaded with channels for blood vessels. As the animal ages, the bone is eaten away and rebuilt piece by piece, and the cross-section fills with small rings crowded into one another.

In 2010 a team led by Koen Stein cut *Magyarosaurus* bones of different sizes. All of them, including the smallest humerus (upper arm bone), a quarter the length of the large humerus it was compared with, had tissue rebuilt almost throughout. They were adults.

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*.

## Where the bones came out of the ground

Each point is a place from which at least one bone, tooth, egg or footprint of a dinosaur or pterosaur has been collected and then described in a study. Tap a point to see what was found there.

### Almost everything comes from two corners of Transylvania

The red points date from the last few million years of the Cretaceous. The green ones are far older.

### The Hațeg Basin

The first bones were found here, at Sânpetru, in the Sibișel valley. Vălioara gave *Hatzegopteryx* and *Uriash*. At Tuștea a landslide in the late 1980s uncovered the first nests of dinosaur eggs in Central and Eastern Europe. At Totești 11 clutches of a dwarf titanosaur were found, with eggs about 12 centimetres across. The red-toothed mammals lived at Pui.

### Sebeș and Alba Iulia

Sebeș Glod gave *Balaur* and the pterosaur *Eurazhdarcho*, with a wingspan of about 3 metres. Râpa Roșie gave the giant pterosaur bones. The skull of the crocodile *Allodaposuchus* was found at Oarda de Jos. Petrești has the oldest layers, from the end of the Campanian.

### Cornet, Bihor: 70 million years earlier

In July 1978 a blast in a bauxite mine in the Pădurea Craiului hills opened a pocket full of bones. The Țara Crișurilor Museum in Oradea took thousands of bones out of it, mostly of plant-eating dinosaurs from the start of the Cretaceous. This place too had been an island, and the iguanodont here was a quarter to a third the size of those in western Europe. Whether they were adults has not yet been checked in the bone.

### Anina, Caraș-Severin: the oldest traces on the map

In a quarry at Colonia Cehă, according to a 2009 study by Grzegorz Pieńkowski, Mihai Popa and Artur Kędzior, sauropod footprints were found from the Hettangian, at the start of the Jurassic.

### Dobrogea: the tooth of a large meat-eater

A tooth found more than a century ago in southern Dobrogea was re-examined in 2016. It belongs to a carcharodontosaurid, a large meat-eater, from the Valanginian, early in the Cretaceous: the oldest known from the Cretaceous when the study appeared. So at least one large predator lived on the broad dry land of Dobrogea.

### And three more points

Jibou in Sălaj, Iara in Cluj and Borod in Bihor have one or two recorded fossils each. The map shows where people have searched and published; dinosaurs also lived in places where the right rocks never reached the surface.

## Ilona found the first bones

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.

Franz searched the place that same summer and found a skull. He enrolled at the University of Vienna, and at 20 he published his first note on the bones from home. In June 1899 he presented the skull to the Vienna Academy under the name *Limnosaurus*. The name already belonged to another animal, so in 1903 he changed it to *Telmatosaurus*.

By 1929 he had published five monographs and described ten Hațeg animals, among them *Struthiosaurus*, the sauropod that became *Magyarosaurus*, and the turtle *Kallokibotion*. He cared about how dinosaurs lived: he wrote, for instance, about how males might differ from females. His second passion was Albania, on which he published more than 40 works.

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?

## True or false?

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

- **Balaur bondoc had two sickle claws on each foot.** True. Its first toe had grown almost as large as the second, giving it a double set of big claws. In its relatives only the second toe carries the sickle. ([Csiki et al. 2010, PNAS](https://doi.org/10.1073/pnas.1006970107))

- **Magyarosaurus was just the baby of a giant sauropod.** False. Thin slices of its bones under the microscope show adult tissue, rebuilt many times over, even in the smallest individuals. It was fully grown and weighed under a tonne. ([Stein et al. 2010, PNAS](https://doi.org/10.1073/pnas.1000781107))

- **Hatzegopteryx was a dinosaur.** False. It was a pterosaur, a flying reptile of the azhdarchid family. Pterosaurs are close relatives of dinosaurs but form a separate group. ([Naish & Witton 2017, PeerJ](https://doi.org/10.7717/peerj.2908))

- **The first dinosaur bones at Sânpetru were found by the scientist's sister.** True. In 1895 Ilona Nopcsa, Franz's younger sister, came across fossil bones on the family estate. Franz searched the same summer and found the skull he would go on to describe. ([Grigorescu 2010, Palaeo3](https://doi.org/10.1016/j.palaeo.2010.01.030))

- **Every dinosaur on the island was a dwarf.** False. Uriash kadici, a titanosaur named in 2025, was 8.8 to 11.9 metres long and weighed 5–8 tonnes. The small theropods were no smaller than their mainland relatives either. ([Díez Díaz et al. 2025; Benton et al. 2010](https://doi.org/10.1080/14772019.2024.2441516))

- **The island was about the size of today's Hațeg Country.** False. The working estimate is roughly 80,000 km², about the size of Hispaniola, and other reconstructions go up to 200,000 km². The small figure of 7,500 km², quoted for a while, was acknowledged as a mistake: it was the area of today's basin. ([Benton et al. 2010, Palaeo3](https://doi.org/10.1016/j.palaeo.2010.01.026))

- **A mammal with red teeth lived on the island.** True. Barbatodon transylvanicus, found at Pui, had red enamel on the front of its incisors and on the cusps of its cheek teeth. The colour comes from iron, as in today's shrews and rodents. ([Smith & Codrea 2015, PLoS ONE](https://doi.org/10.1371/journal.pone.0132550))

- **A Hațeg dinosaur long treated as an Iguanodon relative was reclassified in 2026 as an early relative of Triceratops.** True. A study from January 2026 placed the species Zalmoxes shqiperorum among the ceratopsians under the new name Ferenceratops. According to the Natural History Museum in London, the name honours Ferenc (Franz) Nopcsa. It was an early member of the group, not a horned animal like Triceratops. ([Maidment et al. 2026, Nature](https://doi.org/10.1038/s41586-025-09897-w))

## What you can see in Hațeg Country today

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.

Opening hours and prices change with the season; check them on the [geopark's website](https://www.hateggeoparc.ro/) before you travel. The site of the Tuștea nests is now abandoned and overgrown.

- **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.

## How we know all this

Measurements and dates come from published studies; where only the abstract could be read, or the article could not be opened, the list below says so. Where sources give different values, the range is printed. The length of *Magyarosaurus* is the most important case: 6 metres in Nopcsa and in a 2021 paper, under 3 metres in the 2025 revision, which is followed here.

Three things you will meet elsewhere are absent here because no primary source for them was found: the length of *Balaur*, Ilona Nopcsa's age in 1895, and the standing height of *Hatzegopteryx*.

- Benton, Csiki, Grigorescu, Redelstorff, Sander, Stein, Weishampel (2010). Dinosaurs and the island rule: The dwarfed dinosaurs from Haţeg Island. Palaeogeography, Palaeoclimatology, Palaeoecology 293. https://doi.org/10.1016/j.palaeo.2010.01.026 — island size, climate, lengths of Telmatosaurus and Zalmoxes, Nopcsa's 1912 idea
- Csiki-Sava, Buffetaut, Ősi, Pereda-Suberbiola, Brusatte (2015). Island life in the Cretaceous. ZooKeys 469. https://doi.org/10.3897/zookeys.469.8439 — the European archipelago, latitude, dating, the fauna, Struthiosaurus
- Blanco, Puértolas-Pascual, Marmi, Vila, Sellés (2014). Allodaposuchus palustris sp. nov. … PLoS ONE 9(12): e115837. https://doi.org/10.1371/journal.pone.0115837 — the map of Maastrichtian Europe, redrawn here
- Csiki-Sava, Vremir, Vasile, Brusatte, Dyke, Naish, Norell, Totoianu (2016). The East Side Story. Cretaceous Research 57. https://doi.org/10.1016/j.cretres.2015.09.003 — how close to the end of the Cretaceous the fossils come (abstract only)
- Stein, Csiki, Curry Rogers, Weishampel, Redelstorff, Carballido, Sander (2010). Small body size and extreme cortical bone remodeling indicate phyletic dwarfism in Magyarosaurus dacus. PNAS 107(20). https://doi.org/10.1073/pnas.1000781107 — the bone evidence that Magyarosaurus was adult
- Díez Díaz, Mannion, Csiki-Sava, Upchurch (2025). Revision of Romanian sauropod dinosaurs … Journal of Systematic Palaeontology 23(1). https://doi.org/10.1080/14772019.2024.2441516 — titanosaur lengths and masses, Uriash and Petrustitan (accepted manuscript read)
- Naish, Witton (2017). Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked arch predators. PeerJ 5: e2908. https://doi.org/10.7717/peerj.2908 — Hatzegopteryx: wingspan, neck, the predator hypothesis
- Vremir, Kellner, Naish, Dyke (2013). A new azhdarchid pterosaur from the Late Cretaceous of the Transylvanian Basin. PLoS ONE 8(1): e54268. https://doi.org/10.1371/journal.pone.0054268 — Eurazhdarcho and the giant bones from Râpa Roșie
- Csiki, Vremir, Brusatte, Norell (2010). An aberrant island-dwelling theropod dinosaur from the Late Cretaceous of Romania. PNAS 107(35). https://doi.org/10.1073/pnas.1006970107 — the description of Balaur bondoc
- Brusatte, Vremir, Csiki-Sava, Turner, Watanabe, Erickson, Norell (2013). The osteology of Balaur bondoc. Bulletin of the AMNH 374. https://digitallibrary.amnh.org/items/a10f497d-fbe1-41e2-bc2c-b291d44aa8c8 — place and date of the discovery
- Cau, Brougham, Naish (2015). The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc. PeerJ 3: e1032. https://doi.org/10.7717/peerj.1032 — Balaur as a flightless bird
- Maidment, Butler, Brusatte, Meade, Augustin, Csiki-Sava, Ősi (2026). A hidden diversity of ceratopsian dinosaurs in Late Cretaceous Europe. Nature. https://doi.org/10.1038/s41586-025-09897-w — Ferenceratops (abstract and figure captions read)
- Smith, Codrea (2015). Red iron-pigmented tooth enamel in a multituberculate mammal from the Late Cretaceous Transylvanian “Haţeg Island”. PLoS ONE 10(7). https://doi.org/10.1371/journal.pone.0132550 — the red teeth
- Csiki-Sava, Vremir, Meng, Brusatte, Norell (2018). Dome-headed, small-brained island mammal from the Late Cretaceous of Romania. PNAS 115(19). https://doi.org/10.1073/pnas.1801143115 — Litovoi
- Grigorescu (2010). The Latest Cretaceous fauna with dinosaurs and mammals from the Haţeg Basin — A historical overview. Palaeogeography, Palaeoclimatology, Palaeoecology 293. https://doi.org/10.1016/j.palaeo.2010.01.030 — Ilona and Franz Nopcsa, publication years, the 1977 restart
- Csiki-Sava, Andrășanu (2021). Meeting Island Dwarfs and Giants of the Cretaceous – The Hațeg Country UNESCO Global Geopark. Geoconservation Research 4(2). https://doi.org/10.30486/gcr.2021.1926581.1089 — Tuștea, the geopark houses, what can be visited
- Hațeg Country UNESCO Global Geopark, “Istoric” (history) page, in Romanian. https://www.hateggeoparc.ro/new/index.php/istoric/ — the geopark's dates
- Grellet-Tinner, Codrea, Folie, Higa, Smith (2012). First evidence of reproductive adaptation to “island effect” of a dwarf Cretaceous Romanian titanosaur. PLoS ONE 7(3). https://doi.org/10.1371/journal.pone.0032051 — the Totești clutches
- The Paleobiology Database, collections with Dinosauria and Pterosauria in Romania, downloaded 19 September 2026. https://paleobiodb.org/ — the points on the map
- Benton, Cook, Grigorescu, Popa, Tallódi (1997). Dinosaurs and other tetrapods in an Early Cretaceous bauxite-filled fissure, northwestern Romania. Palaeogeography, Palaeoclimatology, Palaeoecology 130. https://benton.blogs.bristol.ac.uk/files/2019/07/1997Romania.pdf — Cornet
- Csiki-Sava, Brusatte, Vasile (2016). “Megalosaurus cf. superbus” from southeastern Romania: the oldest known Cretaceous carcharodontosaurid. Cretaceous Research 60. https://doi.org/10.1016/j.cretres.2015.12.004 — the Dobrogea tooth (abstract only)
- Pieńkowski, Popa, Kędzior (2009). Early Jurassic sauropod footprints of the Southern Carpathians, Romania. Geological Quarterly 53(4). https://gq.pgi.gov.pl/article/view/7534 — the Anina tracks (the article could not be opened; details come from the database)