Tersuron

The Tersurons, (PROSE: Unnatural History) Tersurans, (PROSE: The Taking of Planet 5) or Tersurrans (PROSE: Cat's Cradle: Time's Crucible) were the native species of Tersurus. They were the nicest race in the universe, but also the most shunned and loathed as they spoke Tersuran, a language of controlled farts. (TV: The Curse of Fatal Death)

In the Old Time and Dark Times, they had some association with the early Time Lords. (PROSE: Cat's Cradle: Time's Crucible, Lungbarrow)

History
Along with the Delphons, the Fendahl Predator consumed the Tersurans' best forms of communication, so they had to evolve for the most tenuous forms of communication. (PROSE: The Taking of Planet 5) In the Tersurons' case, this was Tersuran, a language of controlled farts. (TV: The Curse of Fatal Death)

Tersuran Airfresh was a product Prubert Gastridge once did a commercial for. (PROSE: The Tomorrow Windows)

The Tersurons were able to build sizeable castles. The architect of Castle Tersurus was subject to various bribes by the Ninth Doctor and the Master in attempts to to make the other fall into traps while anticipating that they would later bribe the architect to do the same. One of these included a vast sewer system that took the Master centuries to escape.

After discovering fire, all the Tersuran-speaking Tersurons went extinct. (TV: The Curse of Fatal Death)