The Vulcan marsupial was an animal native to Vulcan.
One of the tasks on an Enterprise bingo checklist was to get the medical tricorder to register a Vulcan marsupial. (SNW: "Spock Amok")
It was misspelled on the list as "marupial".
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")