The Club Penguin App (formerly called My Penguin) has updated to it's recent version: version 1.6.14 for all mobile devices that the application is available on. They have updated it for the Prehistoric Party 2016 that was released January 20. If you have iOS 7 or Android 4.0.3 (or later) you can download it.
The updates include the ability to access the Prehistoric Party features, such as purchasing a Dino Puffle, and transforming into a dinosaur.
Here is the icon for the app. It is a caveguin with the appropriate headgear.
Here is the description of the iTunes store description:
"Go back in time during Club Penguin's Prehistoric Party Jan. 21-Feb. 3! Collect power fragments from the past to help get the alien puffles home!
Members can adopt dino puffles from Jan. 21- Feb. 3"