The Merchokans were a species native to the region where the Steranmio Alliance and Pilmarian Union of Planets operated.
Merchokans had light green-colored skin and two hearts, and they were usually tall and thin.
A Merchokan was a colleague of Ghikadi Thall. He suffered bi-cardiac arrest and died in the Vendoth attack on the USS Determination (NX-78236) in 2376. (Star Trek: The Cantabrian Expeditions: "Howl")