Vortisaur

Vortisaurs were pterodactyl-like creatures who lived in the Vortex.

Biology
The Doctor described vortisaurs as birds of prey. (BFA: Storm Warning) They were large enough to support a human-sized creature. (BFA: Storm Warning, BBCR/BFA: No More Lies) In the Vortex, Vortisaurs were drawn to the chronal distortions radiated by objects passing through. They would occasionally scavenge from ships wrecked and lost there. Their jaws were fixed with sharp teeth; on biting, beyond the physical wound, the chronal energies of the creature aged the wound and the surrounding tissue by decades. (BFA: Storm Warning)

History
The Vortisaurs were known to the Time Lords. The Doctor had ridden them bareback while at the Academy and was proficient in handling them. (BFA: Storm Warning)

Fitz Kreiner once compared them to Vortex Wraiths, calling them more common and less chaotic inhabitants of the vortex. (EDA: The Slow Empire) The Doctor encountered a flock of Vortisaurs scavenging from the hulk of a time ship; his efforts to drive them off only resulted in him being attacked himself. Although he managed to retreat to 1930 France, materialising his TARDIS on board the airship R101, he unknowingly towed one of the creatures along with him, a fact revealed when it began to attack the airship crew. The Doctor and his new companion Charley Pollard then ride it to escape the crash of the airship. Charley took a liking to the Vortisaur, naming it Ramsey after the Prime Minister of her time, James Ramsay MacDonald. (BFA: Storm Warning) After a number of failed domestication attempts, Ramsay was eventually released back into the Vortex. (BFA: Minuet in Hell)

The Doctor also encountered Vortisaurs ridden by Tar Modowk. He rode one of these Vortisaurs, naming it Margaret. (BBCR/BFA: No More Lies)

When the Monk used a time scoop in an attempt to capture the Doctor's TARDIS, he accidently pulled a Vortisaur out of the time vortex. (BFA: The Book of Kells)