Fragmentary fossils of huge azhdarchid pterosaurs have been found in Canada since the early 1970s, and for a long time they were assumed to belong to Quetzalcoatlus. But more recently these remains were re-examined and shown to actually represent an entirely new genus and species.
Cryodrakon boreas – an excellent name meaning “icy dragon of the north wind” – was officially described in late 2019. With a wingspan of around 10m (32’10”) it was similar in size to its close relative Quetzalcoatlus, but it dates to about 10 million years earlier making it one of the oldest azhdarchids ever found in North America.
It lived about 76 million years ago in Alberta, with its fossils coming from the Dinosaur Park Formation, an area that at the time would have been a coastal plain near the northern parts of the Western Interior Seaway. Despite Alberta being located somewhat closer to the Arctic Circle than it is today, the climate was warm-temperate and temperatures rarely dipped below freezing, with short nights in the summers and only a few hours of daylight in the winters.
Like other azhdarchids Cryodrakon would have spent a lot of its time on all fours on the ground. While moving like that it would have been almost 5m tall (16’5″), similar in size to a modern giraffe, stalking smaller animals and eating whatever it could catch and fit into its mouth.
Fossils of pterosaurs are already rather rare due to their fragile hollow bones — and they’re especially scarce in Australia, with only a handful of fragments known.
But recently a more complete one was discovered in central-western Queensland.
Ferrodraco lentoni (“Lenton‘s iron dragon”) is named after the ironstone that the fossils were found in, and while it’s known only from a partial skull, some pieces of its neck and wings, and various teeth, it’s still by far the best pterosaur specimen ever found in Australia.
Living during the mid-Cretaceous, somewhere between 94 and 90 million years ago, it had a 4m wingspan (~13′) and was also one of the very last of its kind. It was a member of the ornithocheirids, a group characterized by rounded crests at the tips of their long toothy jaws, which were previously thought to have all gone extinct by that time.
Many of Australia’s Cretaceous animals were close relatives of those found in South America, due to an earlier land connection via Antarctica, but surprisingly Ferrodraco wasn’t particularly closely related to any South American ornithocheirids. Instead it seems to have been part of a lineage known from halfway around the world in Europe, suggesting that these pterosaurs were capable of crossing long distances over oceans to disperse between continents.
There are no big theropod dinosaurs known from the end-Cretaceous Hațeg Island ecosystem, but that doesn’t mean there weren’t any large carnivores at all.
The apex predator niche here instead seems to have been occupied by Hatzegopteryx, an enormous azhdarchid pterosaur. Standing up to 4.5m tall (14’9″) when on the ground, and with an estimated wingspan rivaling Quetzalcoatlus (~11m / 36′), it was one of the largest animals to ever fly – although like other azhdarchids it probably actually spent most of its time stalking around quadrupedally on the ground eating whatever it could fit into its mouth.
Its neck was shorter and chunkier than most other azhdarchids, and its skull was wider and more massively built. The walls of its hollow bones were also unusually thick and reinforced for a pterosaur, so much so that they were initially mistaken for those of a theropod instead.
Fossils of Hatzegopteryx are very fragmentary, however, so its full appearance and the specifics of its diet are still uncertain. But it would have probably been able to tackle much larger prey than other azhdarchids, possibly capable of using its sturdy beak to bludgeon or stab anything too big to pick up and swallow whole in a similar manner to modern marabou storks.
Cycnorhamphus suevicus, a pterosaur from the Late Jurassic of Germany and France (~150-145 mya).
It had a wingspan of about 1.3m (4′3″), and was originally thought to look similar to Pterodactylus with long straight jaws – but a well-preserved fossil nicknamed “the Painten Pelican” revealed its snout was actually much more oddly-shaped.
It turns out Cycnorhamphus’s jaws arced outwards, creating an opening that seems to have become more pronounced as individuals reached adulthood. Soft-tissue impressions in the fossil also show some sort of stiff “flanges” on each side of the upper jaws, covering the gap and giving it a sort of bulldog-like appearance.
The function of this jaw structure is unknown for certain, but it’s been speculated to be a specialization for cracking open hard-shelled prey like molluscs.
Caviramus schesaplanensis, a pterosaur from the Late Triassic of Switzerland (~205 mya). Known from two fossil specimens – a partial jaw and a much more complete skull and skeleton – it was about the size of a modern raven, with a length of around 60cm (2′) and a wingspan of 1.35m (4′5″).
(The more complete fossil is also sometimes considered to be a separate genus and species, Raeticodactylus filisurensis, depending on which pterosaur specialist you ask. If it was a different animal it still would have been very closely related to Caviramus, though, and the two would likely have looked very similar to each other.)
It had some odd anatomy for an early pterosaur, with proportionally long and slender limbs and a fairly heavily-built skull. There were bony crests on both its upper and lower jaws, with the upper crest probably supporting a much larger soft-tissue structure.
Powerful jaw muscles along with a combination of fang-like teeth at the front of its jaws and and serrated slicing-chewing teeth further back suggest it was specialized for eating particularly tough foods such as hard-shelled invertebrates – and it may even have been omnivorous, capable of eating plant matter as well.