Professor Robert Crater in 2266.
Professor Robert Crater was a reclusive Federation archaeologist and husband to Nancy Crater.
In 2261, Robert and Nancy began an expedition on M-113 to conduct a survey of the planet's many ruins. Unknown at the time of the Crater expedition, a single surviving member of the "salt vampire" race continued to live on the planet. It would eventually kill Nancy and would continue to live along with Robert until 2266. Robert would eventually be killed that year, by the "salt vampire", aboard the USS Enterprise.
Reference
- TOS: "The Man Trap"