During the late Cretaceous, 100 to 66 million years ago, a large island was perched in the Tethys Sea at least 200 kilometers (120 miles) away from the landmasses that would later form Central Europe, the Balkans, the Iberian Peninsula, and the Adriatic area of the Mediterranean. Upon this isolated chunk of land, called Ha?eg Island, a number of strange creatures evolved, including dwarf dinosaurs, giant lizards, unique early mammals, and several genera of massive pterosaurs.
Now, a team of five palaeontologists suggest that a new type of giant – and possibly flightless – pterosaur was also on the island, based on an analysis of a jawbone that had been sitting in a Hungarian museum collection for 30 years.
“It is not the largest pterosaur ever found, but it is the largest mandible [lower jaw] recovered to date, with a reconstructed length of 110 to 130 centimeters [43 to 51 inches],” lead author Mátyás Vremir told National Geographic. “This might indicate a very large size pterosaur – possibly of 8 to 9 meters [26 to 29 feet] in wingspan.”
Writing in the journal Lethaia, Vremir and his colleagues speculate that the specimen was a member of the Azhdarchidae family, a widespread group of pterosaurs that outlived other lineages of the winged reptiles (tempting as it is to lump them together, pterosaurs were not dinosaurs).
Azhdarchids appear to have come in a variety of sizes but stuck with two main morphological flavors: Those with extremely elongated, narrow skulls perched on graceful necks; and those with shorter skulls and thicker necks.
Although they have only recovered tantalizing fossil fragments, the current evidence suggests that while Azhdarchids of both shapes inhabited Ha?eg, the largest species stuck to the latter form.
In 2017, a handful of bones found in Transylvania led to the description of an enormous new Azhdarchid genus – named Hatzegopteryx – estimated to be as tall as giraffe when standing on its hindlimbs and have a wingspan of 10 meters (33 feet).
And in 2009, Vremir discovered an even larger specimen of Ha?eg pterosaur, though its genus has yet to be determined. Nicknamed “Dracula”, the animal’s wingspan may have been up to 20 meters (66 feet).
Given that the current study's mandible is a similar size to that of a Hatzegopteryx, Vremir’s team concedes it is possible that the latest specimen was actually another example of the known genus. But due to features reminiscent of a related but non-Azhdarchid pterosaur called Bakonydraco, the team believes the pterosaur may have actually had a relatively bigger, more robust head than Hatzegopteryx and a smaller body.
The authors hypothesize that the specimen was an apex predator that used its powerful muscular jaws to munch on freshwater turtles and large dinosaur eggs. Following a similar evolutionary pattern to the flightless birds of Madagascar and New Zealand, the pterosaurs likely developed stockier, more powerful bodies and lost their ability to fly in response to the unique conditions of island life.
“Islands are notorious for throwing up oddities. We have a bunch of weird dinosaurs from Ha?eg and a lack of really big carnivores, so the pterosaurs were basically tyrannosaur surrogates,” Dave Hone, a London-based palaeontologist not involved in the research, told National Geographic.
[H/T: National Geographic]
