Chronosaurus is a weird small-press RPG published in Germany that allows you to play sentient, time-traveling dinosaurs.
Like humans, the dinosaurs evolved into several sentient races 65 million years ago. They formed highly advanced, civilized cultures. A bad problem was the appearance of a huge comet that would strike Earth. When it became clear that an escape to another place was not possible, a quirky dinosaur inventor managed to create a time machine to allow escape to another time. The one time machine alone was not capable of rescuing the whole dinosaur civilization, but building more was made impossible, because the inventor vanished through his creation and only left some cryptic notes on time coordinates.
This is where a Chronosaurus campaign starts. The player characters are dinosaur scientists that have to jump to those time coordinates in search of the lost inventor. This is a bit like Stargate: You never know where (or when) you land. At most destinations, some earlier vanguard expeditions - sent by the inventor, usually voluntarily - have formed small dinosaur communities. But the characters will also meet humans that much later in Earth's timeline rose to become the masters of the planet.
The game system cannot be called such. It is completely diceless and has no other rules to influence the story. It relies solely on the common sense of players and the game master and on the power of good conversation and role-playing. The game gives advice on how to achieve that, but declares no fixed rules for it.
Although the system has no rules, there is of course a character creation process. The selection of a dinosaur races defines a basic mindset for the character, his outward appearance and his abilities. There are also several occupations to chose from, mostly scientific. Characters will be doctors, ethnologists, psychologists, journalists, and the like. This defines not only a characters main field of knowledge, but also a small dictionary of technical terms to flesh out the role with some quirky language.