The Vulcan marsupial was an animal native to Vulcan.
When The Doctor from the USS Voyager was trying to find a cure for Doctor Lewis Zimmerman's illness in 2376, the holo-engineer manipulated The Doctor's tricorder so that it would display a mitochondrial scan of a Vulcan marsupial. It took The Doctor a full hour to find out what was wrong with the scan. (VOY: "Life Line")