Paleontologists assigned them to the genus Quetzalcoatlus, given that it was the only known azhdarchid from North America back then and because they had limited information about its actual remains, so they simply could not deduce anything different.

But it was not until 2019 that it received a new genus and type species, Cryodrakon boreas, named and described by paleontologists David Hone, Michael Habib, and François Therrien.

However, much larger fossils have been unearthed, including an incomplete fifth cervical (neck) vertebra that measures 40 cm (1 ft 4 in).

A phylogenetic analysis was not performed due to the fragmentary nature of its remains, but the describers pointed out certain features that would exclude Cryodrakon from being in a basal (primitive) position within Azhdarchidae.

Later research by American paleontologist Michael Habib would indicate that these fossil remains represented a taxon that was new to science.

[3][2] In 2019, specimen TMP 1992.83 received a new separate genus and type species, Cryodrakon boreas, and became the holotype of this new pterosaur.

Cryodrakon boreas was named and described by paleontologists David Hone and François Therrien, alongside Habib.

The generic name Cryodrakon is derived from the Ancient Greek words κρύος (kryos, meaning "cold") and δράκων (drakon, meaning "dragon"), while the specific name boreas refers to the Greek god the north wind, Boreas.

[2] Habib had previously considered the name Cryodrakon viserion, as a reference to the ice dragon in Game of Thrones.

The specimens consisted of numerous cervical vertebrae, a scapulocoracoid, an ulna, several fourth metacarpals, wing finger phalanges and a femur.

For example, specimen TMP 1996.12.369, a fifth cervical vertebra with a length of only 10.6 mm (0.42 in), is from a juvenile Cryodrakon, which was given an estimated wingspan of about 2 m (6 ft 7 in).

[5][2] However, nowadays, wingspan estimates for Q. northropi have been more moderate, at around 10 to 11 m (33 to 36 ft), which would still make it one of the largest flying animals to ever exist.

[9][14] In terms of body structure, Cryodrakon was proportionally similar to Quetzalcoatlus and other long-necked advanced members of the Azhdarchidae, though its somewhat more robust bones may indicate that it was slightly heavier.

The second distinguishing feature related to its postexapophyses, large bony knobs adjacent to the protruding rear connection surface of each vertebra, the cotyle.

Additionally, based on the geological age of its fossil remains, Cryodrakon would have been one of the oldest known North American azhdarchids.

[15] In 2023, a study by paleontologist Rodrigo Pêgas and collagues also recovered Cryodrakon within Quetzalcoatlinae, but differed from Andres in its specific position within the subfamily.

Azhdarcho lancicollis Albadraco tharmisensis Aerotitan sudamericanus Mistralazhdarcho maggii Aralazhdarcho bostobensis Phosphatodraco mauritanicus Eurazhdarcho langendorfensis Zhejiangopterus linhaiensis Wellnhopterus brevirostris Cryodrakon boreas Hatzegopteryx thambema Arambourgiania philadelphiae Quetzalcoatlus lawsoni Quetzalcoatlus northropi Topology 2: Pêgas and colleagues (2023).

[19] There was a great diversity of herbivorous dinosaurs including both lambeosaurine and saurolophine hadrosaurs, centrosaurine and chasmosaurine ceratopsians, and nodosaurid and ankylosaurid ankylosaurs, which could have been able to feed on different vegetation levels from one another.