Balaur the stocky dragon – Velociraptor’s double-clawed Romanian cousin

By Ed Yong | August 30, 2010 3:00 pm

Balaur

The “killing claw” of Velociraptor has been a fixture of popular imagination ever since it tapped its way across a kitchen floor in Jurassic Park. But if Velociraptor became iconic, then its close relative Balaur should be doubly so; this newly discovered dinosaur had two sickle-shaped claws on each foot. And unlike the lithe, agile form of its cousin, Balaur was built for strength, with the build of a kickboxer rather than a sprinter.

Balaur bondoc was discovered in Romania by Zoltán Csiki from the University of Bucharest and in Romanian, its name means “stocky dragon”. It lived in the late Cretaceous period. Back then, Europe was a fragmented series of islands rather than a solid landmass. The strange body of Balaur – very different to those of other raptors (or dromaeosaurids) – is testament to the fact that islands have always been great places for natural selection to try out some wacky stuff.

Cut off in a world of their own, island species face different evolutionary pressures to their relatives on the mainland. As such, islands are a hotbed for the bizarre and unique, the small and the giant. The Galapagos islands, for example, are home to flightless cormorants, marine iguanas and giant tortoises.

In recent years, several dwarf plant-eating dinosaurs have been discovered in Romania, cementing a century-old idea initially proposed by the Hungarian adventurer Baron Franz Nopsca. Many of the species were half the size of their relatives elsewhere; Magyarosaurus, for example, was one of the thundering sauropods but it was no taller than a human.

But on this island of dwarf dinos, Balaur was an exception. It’s one of the best examples – living or extinct – of the “island effect” shaping the body of a predator in unusual ways. While weird bodies are the norm for island-dwelling plant-eaters, meat-eaters tend to be just bigger or smaller versions of their mainland relatives. Balaur may be bigger but it’s very different too.

So far, Csiki has only found part of the animal’s skeleton but these fragments are enough to show that Balaur was a feast of odd features. For a start, many of its wrist and hand bones had fused together and one of its fingers was unusually stunted. This wasn’t a predator that could easily grasp its prey. Instead, its main weapons were its legs.

Many of its leg and foot bones had fused together too and their short, stocky shape would have made them very shock-resistant. This animal probably didn’t have the speed or agility of its smaller relatives. What it did have was strength. Its barrel-shaped torso had large hips with powerful leg muscles. With these, it could lash out with a forceful kick, attacking prey with feet that were each armed with two extendable, sickle-shaped claws.

Csiki says that the legs “would have allowed [Balaur] to subdue its prey more easily by itself, with deadly kicking blows, instead of trying to seize it (as in Velociraptor) or hunt it down in pack (as was suggested for Deinonychus, another close relative).” But he adds, with a note of caution and tongue firmly in cheek, “This is still extremely speculative. It might have been herbivorous, digging out carrots with the two large hyper-extensive claws!”

Balaur’s features are big departure from the basic raptor body plan – all other species were lithe hunters with just one killing claw on each foot. With such unusual traits, you might think that Balaur was an early offshoot from the raptor dynasty but in fact, it was deeply nested within it. Its closest relative was the limelight-hogging Velociraptor.

Balaur’s position in the dinosaur family tree also changes our understanding of evolution in Cretaceous Europe. Until now, scientists had thought that Romania was the bastion of species that has been stranded from the mainland since the much earlier Jurassic period. The dwarf plant-eaters support that idea because they’re all very early members of their respective families, each bearing a number of primitive characteristics. But Balaur doesn’t fit that bill – it’s arose fairly late in raptor history, and its closest relatives came from Asia. Some sort of species exchange programme must still have been operating between Europe and Asia well into the Cretaceous period.

Reference: PNAS http://dx.doi.org/10.1073/pnas.1006970107

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CATEGORIZED UNDER: Dinosaurs, Evolution, Palaeontology

Comments (10)

  1. “[…] around 60 million years ago”. Wouldn’t it better to say around *65* mya? Even children (well, especially children) know that dinosaurs went extinct about 65 mya. In my mind, 60 mya is already mammals age. Ah, am I pedantic

  2. The “killing claw” in question properly belongs not to the velociraptor (which was about the size of a turkey) but to Deinonychus, which Jurassic Park’s velociraptors more closely resembled (for example, we’re not absolutely *certain* Deinonychus had feathers.)

    I mean, they probably did, but so far as I know, no direct evidence of feathers have been found with Deinonychus

  3. zackoz

    I take it that the slight doubt about whether Balaur was carnivorous arises because no teeth have been found?

    Otherwise, the researcher’s caution (even if tongue in cheek) is a bit hard to understand.

    The illustration seems to indicate no cranial material came to light.

  4. Oh, the creationists will have a heyday with that carrot remark…. even when Csiki was only kidding when he said it.

  5. Katharine

    Is this from the Hateg formation near Hunedoara?

    Transylvania is just swimming in dinosaurs around there.

    (by the way, Balaur bondoc translates to ‘dragon runt’. I am moderately proficient in Romanian myself.)

  6. Katharine

    Oh. You mentioned an island. Yup, that’s Hateg.

  7. @ Katharine – I took the translation straight from the paper ;-)

    Also I love the fact that a Reddit commenter said “It’s like the Gillettiraptor. Soon, it will have 3 claws, and then 5!”

    Heh. “The first claw kills close. The second claw kills closer.”

  8. There’s an interesting discussion going on at Facebook between myself, Andrea Cau, and Ville Sinkhoven regarding the possibility that Balaur was more graviportal than other dromaeosaurs, it walked on all four toes, and the pubis/ischium were affected by portmortem distortion. In other words, what we might have here is a therizinosaur mimic. That would be very awesome!

  9. Velox

    Would it be possible, perhaps, that the stunted finger could be the result of a genetic anomaly? I’ve seen a human hand with such a deformity where two fingers were extremely stunted, and I’ve heard tell of other animals with similar deformities. I suppose only time and more specimens will tell. It could be possible that such a stunted finger could help to reduce weight in a bulky body plan. But how cool would it be for such a deformity to have been preserved?

    I seem to recall reading elsewhere that carnivorous teeth were found on that island previously, but no body. Could it be that Balaur was the owner?

    I’d also be interested in knowing how effective having a second enlarged claw on each foot really could have been.

  10. hello kitty

    Did They Have Feathers?

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