Ortiz (Lieutenant)

Ortiz was a 23rd century Human, a slender man with blond hair.

Biography
By the year 2270, Ortiz was a member of Starfleet with the rank of lieutenant, and served as the low watch science officer aboard the Federation starship USS Cochise (NCC-530).

When the Cochise discovered a gravity anomaly that caused the ship to experience turbulence, Ortiz notified Captain Jeremiah Chandler, who took over the bridge from the low watch crew, and ordered Ortiz to report on what was on the sensors. 

Background
For the purposes of this wiki, a full lieutenant's rank insignia is shown, but it is just as likely Anderson was a lieutenant junior grade addressed as "lieutenant". No insignia was described in the novel.