MALURIANS

Planet of Origin: Malur, a planet in a system containing 3 inhabitable planet in the Sol system vicinity of the  Milky Way galaxy. 

The Malurians are a scaly, gray-skinned humanoid species which had developed a warp-capable spacefaring civilisation as the the 2150ies, at whihc point their total population was of four billion people spread on the four inhabited planets of their sytem.

Wandering off their system, they started to secretely mine the veridium isotope found on the planet Akaali whose inhabitants developed a sickness due to the use of  drilling equipment saturated with tetracyanate 622 by the Malurians.

Their whole population was later wiped out  by the Earth space probe Nomad in 2267.  (TOS: "The Changeling")  (ENT: "Civilization")