Of course the apes are the stars of [Dawn of the Planet of the Apes](movie:322904). One of the groups responsible for the fearsome and tribal looks of the apes are the concept artists from the Aaron Sims Company. Their specialty lied in creating aging effects and a tribal ceremonial look for the apes. They did their job well. These apes are a truly fierce bunch.
ASC also worked closely in designing the ape effects for the first film, Rise of the Planet of the Apes. It also included sculpting busts for most of the main ape characters so the CGI folks can get a hyper-realistic feel for the job.
Via concept art world: http://conceptartworld.com/?p=34978