Tzzz-Tzer-Tzak was a Chenjesu historian whose research indicated the existence of the Sentient Milieu. He was able to find that one of the members of the Milieu was a "race of rocklike creatures" (most likely the Taalo) whose homeworld orbits one of the stars of the Vulpeculae system.
Tzzz-Tzer-Tzak's research was read by Commander Hayes, who then revealed it to The Captain sometime during his first voyage c.2155-59. However on the captains second voyage with the Chmmr Flagship c2165-69 Tzzz-Tzer-Tzak and also his discovery of the Taalo are not mentioned again by Hayes. This is due to the fact that asking him about the Ancient races was removed from the demo of Star Control II:Project 6014.