More context:

This is a Santamartamys rufodorsalis, AKA the Red Crested Tree Rat. Only three specimens have ever been seen, and this is the first photo ever taken.

I found the original article from 2011. Species that are thoight to have gone extinct and then are rediscovered are called Lazarus Taxa, although I don’t know if this guy would count since this is just the third sighting.

https://phys.org/news/2011-05-spectacular-mammal-rediscovered-years-.html