The Arcturians were a Humanoid species. By the mid 2270s, they were serving in Starfleet (Star Trek: The Motion Picture).
Since they had an appreciation for Shakespeare, a popular version of Macbeth was re-envisioned by the Arcturians. Sponsored by the Galactic cultural exchange project this rendition was notably performed by the Karidian company of players a touring theatrical troupe headed by Anton Karidian in 2266 (Star Trek: The conscience of the king
in the revised final draft script of the conscience of the king both a couch that king Duncan is shown dying on and some of the costuming were referred to as being distinctively Arturian regarding the latter, Macbeth and king Duncan were characterised in the Arcturian style.
An Arcturian Starfleet officer was speaking with two Rhaanderites at starfleet headquarters air train station in San Francisco on stardate 7410.2. The three were on a lower platform (in the background) when James T Kirk and Sonak parted ways at the top of stairs
Shortly thereafter, an Acturian crew member from the USS Enterprise attended a mass briefing on the starship's recreational deck (Star Treck: The Motion Picture).
They are supposedly a militaristic race, providing infantry for the Federation. They clone each other resulting in the need for varying uniforms to tell each other apart.