Confederation of the Gorn
The Gorns border both the Federation and the Romulans. The Gorns met (and fought several wars with) the Romulans before discovering the Federation in a famous incident in which two brash young captains shot first and faced embarrassing questions later. After this incident, the Gorns discovered they had much in common with the Federation (including previous wars with the Romulans) and the two empires became fast friends.
The Gorns are a confederation of three worlds on which genetically identical species of dinosauroids existed. Evidence indicates that an unknown ancient race, nicknamed the ‘Lizard Kings’, planted the Gorns on those planets around 11,000 BC.