Prior to her posting aboard Enterprise in 2151, T'Pol had observed a demonstration of a device similar to a replicator on a Tarkalean vessel. She stated that "it was capable of replicating almost any inanimate object." (ENT: "Dead Stop")
Dr. Phlox was able to initially assist the Tarkaleans; however, he discovered that the Borg nanoprobes had infiltrated their autonomic systems and that their renal glands were replaced with cybernetic devices. The Tarkaleans eventually succumbed to the Borg and one of the Tarkaleans attacked and injected Phlox with nanoprobes. The Tarkaleans later escaped sickbay and attempted to modify the systems of Enterprise, forcing Captain Archer to eject the two into space. (ENT: "Regeneration")
In 2372, the Ferengi imposed an unfair six percent tariff on woolen goods they traded with the Karemma, claiming that the tax was added to help offset the "lost income of Tarkalean sheep herders." (DS9: "Starship Down")
The Tarkaleans, though mentioned often in Star Trek, made their first appearance in "Regeneration".
'Tarkalean' was incorrectly spelled in the script for "Starship Down" as 'Tarkalian', but it believed to be a simple typographical error. A similar error was made in the script for "Hippocratic Oath" where the spelling 'Tarkalian' appeared in the pronunciation guide, but the spelling was later corrected to 'Tarkalean' later on in the script.