A human ancestor was believed to have impressive upper body strength and adaptation skills.

Researchers found 1.34 million-year-old "arm, hand, leg and foot fragments" from an ancient hominid dubbed Paranthropus boisei, a University of Colorado-Denver news release reported.

"This is the first time we've found bones that suggest that this creature was more ruggedly built -- combining terrestrial bipedal locomotion and some arboreal behaviors -- than we'd previously thought," Charles Musiba, Ph.D., associate professor of anthropology at the University of Colorado Denver, said in the news release. "It seems to have more well-formed forearm muscles that were used for climbing, fine-manipulation and all sorts of behavior."

The first P. boisei skull was discovered in 1959. Researchers knew the hominid had an impressive jawbone, but but little was known about the structure of its body. Excavations of the Olduvai Gorge World Heritage fossil site in Tanzania between 2011 and 2012 uncovered the tell-tale bones.

"We are starting to understand the physiology of these individuals of this particular species and how it actually adapted to the kind of habitat it lived in," Musiba said. "We knew about the kind of food it ate -- it was omnivorous, leaning more toward plant material -- but now we know more: how it walked around and now we know it was a tree climber."

The team determined P. boisei had exceptionally strong arms by the size of its arm bones. They had originally believed these bone fragments had come from an older genus known as Australopithecus, which P. boisei may have evolved from.

 "We know that it was very strong," Musiba said. "It's unprecedented to find how strong this individual was. The stronger you are the more adaptive you are."

The fossils are just another piece of the human evolution puzzle.

The more we are finding of these fossils, the more we are learning about the history of these species," Musiba said.