Final answer:
The trait equally shared among all hominoids is upright bipedal locomotion, characterized by a hip structure that supports walking on two legs.
Step-by-step explanation:
One trait shared about equally among all of the hominoids is their upright bipedal locomotion.
Hominoids, including modern humans and our ancestors, demonstrate a distinctive hip structure that supports walking on two legs. This trait has been observed and is significant in early Homo species such as Homo erectus and is also shared with our ancient ancestors like H. habilis and Australopithecus. The shared traits of hominoids also included adaptations in the feet, the reduction of bone mass in the skull and face, and an increase in brain size, particularly in the frontal lobes. These evolutionary developments have been critical for the genus Homo's survival and adaptation to varying climates and environments.