Cryodrakon: Beast of the Week

This week we will be checking out a newly described giant pterosaur.  Check out Cryodrakon boreas!

Cryodrakon was a large pterosaur, a flying reptile related to dinosaurs, that lived in what is now Alberta, Canada, during the late Cretaceous period, between 76 and 77 million years ago.  The fossils that we can definitely assign to this species imply that it had a wingspan of about fifteen feet wide, but an isolated vertebra that may have been from the same species suggest it could have grown even larger.  When alive, Cryodrakon was likely a meat-eater, specializing in snapping up small animals and probably scavenging as well.  The genus and species name translates to "Ice Dragon of the North Wind" in reference to Canada's icy winters.  It should be noted, however, that when Cryodrakon was alive, its environment was much warmer than it is today.

Cryodrakon life reconstruction in watercolors by Christopher DiPiazza

Cryodrakon belonged to the family of pterosaurs called azhdarchidae.  Azhdarchids were the largest animals, let alone pterosaurs, to ever fly.  They are characterized by their long necks and proportionally huge skulls, which were often longer than their torsos.  They were also known to be better at walking around on the ground than other pterosaurs.  The most famous member of this group is Quetzalcoatlus northropii, which was also the first discovered.  That being said, despite being the most well-recognized member, Quetzalcoatlus northropii is only known from very fragmented remains, in the form of one wing.  So for a long while before other members of the family were discovered, we didn't even know what these pterosaurs really looked like.

Cryodrakon has actually been known on the fossil record for decades, but its bones were always suspected to have simply been more material from a smaller species of Quetzalcoatlus, since they both lived in North America.  Recently, however, they were extensively compared to to each other and diagnostic differences were found!  It turns out that the air chambers that are inside the bones, which scientists have found out are unique for different pterosaur species, are differently arranged in Cryodrakon and Quetzalcoatlus in the same bones.

Photo of the right humerus of Cryodrakon.  Credit: Dave Hone.

Cryodrakon is actually known from a pretty good number of fossils.  Scientists have found very young individuals, which would have only had wingspans of about six feet.  The most complete specimen is known from a neck vertebra, ribs, legs, and part of the wing.  Judging by the wing bone, it would have had a wingspan of about sixteen feet.  However, another vertebra from around the same location was found that measures almost two feet long!  This vertebra MAY be from an older Cryodrakon, which would make its max wingspan over thirty feet, which is comparable to the biggest pterosaurs known, like Quetzalcoatlus northropii. However, this one vertebra is badly damaged and it is currently impossible to confirm if it is indeed from an older Cryodrakon or simply a larger species of pterosaur.

That is all for this week!  As always feel free to comment below!

References

Hone, D.; Habib, M.; Therrien, F. (September 2019). "Cryodrakon boreas, gen. et sp. nov., a Late Cretaceous Canadian azhdarchid pterosaur". Journal of Vertebrate Paleontology.