In 2267, Tamura was part of the landing party that visited Eminiar VII. During the mission, Spock asked her for a scientific survey to identify the nature of Vendikar's attack. Her confusing lack of confirmation for the attack was one clue that helped Spock realize the war between Eminiar and Vendikar existed only as a series of computer models.
Later, Spock left her in charge of Mea 3, with instructions to prevent Mea from reporting to a disintegration station, as citizens of Eminiar VII dutifully did when declared casualties. (TOS: "A Taste of Armageddon")
Yeoman Tamura was played by Miko Mayama. The character's name was spelled "Tamula" in the credits, although the closed-captioned script spelled her name as "Tamura" (a typical Japanese family name).
Although Tamura wore security red and not sciences blue, she appeared to report primarily to Spock. This could be because landing party security and any scientific survey activity related to security were under Spock's leadership as First Officer.