Hateg Island



Hateg in the Romanian region of Transylvania has been the center of numerous discoveries in recent years.

Some of these have turned out to be just as terrifying as the dusty old monsters of ancient Transylvanian lore. The Hateg fossils date back to around 69 to 66 million years ago, the Maastrichtian Stage, the very end of the Mesozoic Era.

The Setting

However, the map of Europe was completely different. An arm of the Tethys Ocean, the Paratethys, covered large parts of the continent and it was bordered by a large group of islands.

It was cut off from the Tethys by the newly-forming Alpine region of Austria and Switzerland.

In fact, this part of Europe was made up of numerous isolated islands, some large like the Bohemian Island and Ibero-Occitan Island while the other proper landmasses were in what is now Austria. Hateg and the islands around it were created during the time of the Alpine orogeny, an episode of mountain-building.

At the time there was a tectonic uplift that carried into the Cenozoic Era, and the mountains spanning the Alpine Belt were in creation. These mountains include the Hindu Kush, Himalayas, Pyrenees, Balkans and Carpathians. Hateg Island is the best documented in terms of fossils.

It was probably slightly warm and temperate, and the plant fossils here attest to that. The flora was made up mostly of woodland plants like walnut, beech, birch and members of the berry family.

These include deciduous shrubs like the genus Eurya and its relatives.

The isle itself was roughly as big as modern Hispaniola, hardly a massive place but intriguing all the same.

It was here that celebrated Hungarian paleontologist Franz Nopcsa realized that living on an isolated island with limited resources could cause dwarfism among even the largest animals living there.
This insular dwarfism is a phenomenon that has happened time and again, including during the Mesozoic Era.


Some of the first Hateg fossils were those of the dinosaurs, which had shrunk down to smaller versions of their mainland selves. One of the first known was three species in the genus Struthiosaurus.

This was a small nodosaur, an armored dinosaur which grew to just 2.3 meters in length, hardly even a third the length of its massive relatives elsewhere. The type species of this genus is Struthiosaurus austriacus, described as early as 1871.
Nopcsa himself described the second species, S. transylvanicus in 1915 while the third, S. languedocensis was named in 2003. It was very well protected against any predators on the island although there weren’t many predatory theropods on Hateg.


An even earlier discovery here is the ornithopod genus Rhabdodon, which is actually known from all around Europe. Its remains are known from France’s many Maastrichtian rock formations like Villalaba de la Sierra Formation, Gres de Saint-Chinian, and the Marnes Rogues Inferiures. Fossils have also been found on Hateg.

This widespread animal was a bipedal, beaked herbivore up to 6 meters long at maximum. The type species is Rhabododon priscus, from France while the second-known species is R. septimanicus.
This is also from the same country but a completely different formation and region.


Outside Hateg, there were many larger dinosaurs, like the armored French titanosaur Ampelosaurus. This is known to be a possible dwarf too despite being medium-sized for a sauropod of any kind.

Dwarfism seemed to be the reason for the smaller size of many of the bigger stem-birds on all the European islands. However the Hateg sauropods are the smallest of all.

The titanosaur genus Magyarosaurus was named by von Huene in 1932.

Earlier, the fossil was assigned to the wastebasket name Titanosaurus by Nopcsa himself in 1915. It was called T. dacus, after the Dacian tribe who were overrun by the Romans during the 1st Century AD. The fossils were found in Hungary. Von Huene identified two extra species named M. hungaricus and M. transsylvanicus in the same year. It was soon realized that this was no ordinary titanosaur.

At 6 meters long and just a tonne in weight, Magyarosaurus was around the height of a horse, though still heavier and bulkier by far. It was probably an armored titanosaur as well. Also, we know that this was pretty much one of the commonest herbivores in the region.

Eggs pertaining to either it or its neighbor sauropod Paludititan have been discovered in Hateg, in the Sanpetru Formation. These sauropods had a rather slow growth, probably not as fast as that of their gigantic relatives although they still had a high metabolic rate. Paludititan was probably more closely related to the strange Indian titanosaur Isisaurus. Isisaurus colberti was yet another taxon to be lumped unceremoniously into Titanosaurus.

It had a thick, long vertically-directed neck and short lower arms. The Hateg genus Paludititan was probably rather similar but smaller, at around 6 to 8 meters in length. The type species is P. nalatzensis and was described in 2010.


The island’s theropods though, were not much to look at in some ways. However they do have rather confused taxonomies. The largest mess concerns some of the very smallest theropods here, the three taxa Elopteryx, Bradycneme and Heptasteornis. The genus Elopteryx was named in 1913 on the basis of some fragmentary limb bones by Nopcsa.

They hail from Sanpetru in the Hateg region, and date back to the Maastrichtian Stage of the Late Cretaceous. The genus is thought to be a maniraptoran theropod of some sort, most possibly a troodontid. This would have made it a small omnivore.

Another set of bones was discovered in 1975 from the same area and assigned to the same taxon. These were reclassified soon after as Heptasteornis.

For a while these theropods were grouped as possible owls. Elopteryx nopcsai, the type and only species, has had a very long history of being classified as a Neornithe or anatomically modern bird.

Currently Heptasteornis andrewsi is regarded as an alvarezsaur, a small insect-eater with short arms and just one claw on its hand for digging up termites.

The other alvarezsaur grouped together with these two is Bradycneme draculae, a rather evocative name for an otherwise meek animal. It too was considered to be a prehistoric owl at one point, with a massive height of 2 meters. It was only recently reclassified as an alvarezsaur.

A more intriguing theropod, and yet another victim of classification errors, is the genus Balaur bondoc.

Following its description in 2010 by Csiki, it made waves as a stocky dromaeosaur with a double sickle claw on its foot. This cast it in a predator’s light, possibly kicking its prey to death with its claws. It was much stockier than Velociraptor too, and this might have meant that it was far more adept at taking on larger prey.

It was still small though, around the same length at 1.8 meters. Balaur bondoc means ‘stocky dragon’ with ‘balaur’ being a dragon in Romanian folklore.

While Csiki, the discoverer, envisioned it as a vicious predator, Andrea Cau imagined it as a herbivore or an omnivore, an aberrant dromaeosaur. It had a much more back-swept pubis than most other genera plus it had short arms and a reduced third finger.

Another evaluation was done by Cau in 2015, and it was realized that it was indeed a basal avialan. In fact it was more closely related to Jeholornis, a primitive herbivorous bird. The genus itself was more likely to be a herbivore rather than a carnivore.

It might have behaved like a sort of flightless pheasant or grouse, foraging on the ground for seeds and fruits.

The extra ‘sickle claw’ of Balaur might have been an adaptation for grabbing branches or perching.


The Hateg pterosaurs were the main predators of the island. The first genus known was the azhdarchid Hatzegopteryx.

It was often thought to have been one of the biggest pterosaurs, exceeding or equaling Quetzalcoatlus in size. Now however it is known to be much stockier and shorter in height, while still somewhat heavier.

The head of Hatzegopteryx has always been regarded as being shorter and broader than that of related azhdarchids, which are known for their extreme slimness.

This might be the result of evolution in isolation. While it was still clearly a flight-capable genus, it would have also been a terrestrial stalker, living off the land and so probably limited to Hateg. In fact, Hatzegopteryx is a native to this island. Its wings spanned 10 meters and with a short height of maybe 3 or 4 meters, they were surprisingly long in comparison with other members of its family.

The second Romanian azhdarchid, the small Eurazhdarcho, might also be shorter and thicker-necked than other genera. They were both probable macropredators, using their toothless beaks to pick up smaller avialan and non-avialan dinosaurs and terrestrial crocodiles.