In 2379, a Kolaran band encountered an armed away team from the USS Enterprise-E that was salvaging the android B-4. The Kolarans attacked the away team with machine guns mounted on motorized wheeled vehicles, and chased them away from the planet. (Star Trek Nemesis)
Although not identified on screen, the name "Kolarans" is derived from production notes, call sheets in particular, during the making of Nemesis.
John Logan's script of Star Trek Nemesis didn't include much detail when describing the Kolarans, merely referring to them as "a nomadic tribe of desert aliens." This allowed Michael Westmore a wide parameter to design their look. He felt the "natural way to go" was to base it on lizards. Since he had designed many aliens on lizards before, Westmore avoided a repeat by basing the Kolarans on turtles. "You've got these little, slow interlopers," he observed, "but the coloring and texture and skin tones work so great that it was the animal of choice to base the exterior shapes and coloring on." Westmore directed six makeup artists to paint the Kolaran masks individually, with each artist ultimately painting five masks. "I just told them what we wanted: base it on a hard shell, with a little bit of turtle coloring to it, a desert group. And we really didn't want to make them deep green or anything; it had to be earth tones, like you'd see on the back of a turtle." As with turtles, since they have different patterns and coloring on each shell, the Kolarans were made to look unique. Westmore didn't reveal to the artists what the others were doing, intending each mask to be different. He was pleased with the variances between them, stating, "You put 10 of them together and you know they're from the same race but with different moms." (Star Trek: Communicator issue 142, p. 39)
While six makeup artists were developing the Kolaran masks, other makeup artists meanwhile created the actors' head molds. A crucial detail was accidentally omitted until the last minute. "We had two major sculptures," Michael Westmore explained, sighing. "We got through the design, and just as we started to make the mold, somebody said, 'Well, you know, all these guys are wearing crash helmets underneath the makeup.'" The makeup hadn't been designed to incorporate a helmet underneath, and there wasn't enough time to account for this by restarting the process of creating the molds, this time with a helmet. Instead, the makeup team managed to salvage several weeks of work by making changes to the makeup which had already been crafted. "So we cut it in two, peeled the sculpture off, drilled holes in the plaster head, measured the helmet, and added plaster onto the head to accommodate," Westmore concluded. (Star Trek: Communicator issue 142, p. 39)
The hand weapons used by the Kolarans were actually prop replicas of real present-day weapons with olive-colored fabrics wrapped around various sections. As shown by the It's A Wrap! sale and auction, the weapons were modified replica-guns of the Valtro shotgun,  the FN Herstal P-90,  the Glock 17,  the Vickers machine gun-style jeep-turret guns,  and other carbines.