10 Questions What do you know about Paleontology? Test your knowledge about the age of dinosaurs. AMNH_Official, 04/27/2018 answers Play What is this fossil? a petrified sponge from the ocean floor lava that erupted from an ancient volcano prehistoric poop left by a dinosaur When did the oldest known dinosaur live? about 228 thousand years ago about 228 million years ago about 228 billion years ago When did the last dinosaur become extinct? 25 million years ago 65 million years ago they haven't all become extinct … and 7 more awesome questions! Check them out by clicking “Play”.