An Eocene fossil turtle.

Found in New Zealand, and considered to be different enough from Psephophorus species found in Europe, Egypt, and the United States to be given a separate classification. This turtle is found in Tertiary sediments.

It was first discovered in 1995 and named by Robert Kohler, who was a fan of Terry Pratchett.

Pratchett himself has this to say about it:

         "Of course I’m proud of it. It tickles my imagination. Forty millions years ago this thing was paddling around the globe, eating jellyfish, and now there’s this link to this short bald guy whose own species, at that time, was still saying 'ook'
         I use it as my Human Being test. We all have such a thing, even if we don't like to think of it like that- a little test of the imagination. I mentioned it to another author who immediately said, 'Who do I have to sleep with to get a species named after me?' and she passed. It's the people who look at you sideways and say, 'Is that good?' that you know are pod beings from the planet Zog."

The quote is taken from The Discworld Companion, in the part where they interview Terry Pratchett