Pterodactyl
The Pterodactyl is an EXCLUSIVE pet that was sold in the Exclusive Shop for 500 Robux. It was introduced in the Heaven Update. It was a limited-time pet and is no longer available.
The latest Pet Simulator X value list for Pterodactyl can be found below:

Regular
💎 28,000,000,000 (28b)

Golden
💎 Not Available

Rainbow
💎 Not Available

Dark Matter
💎 Not Available