The diversity of locomotor behaviors in living apes and the incompleteness of documentation have thus far hindered the development of a clear picture of the origins of human bipedalism. The discovery of the fossil skull of a monkey that lived six million years ago has now led to clear answers on the evolution of monkey locomotion.
Clues to the evolution of human movement have emerged from inside the ear of a Lufengpithecus monkey. This was revealed by a study by researchers from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, the Institute of Archeology and Cultural Relics of Yunnan and New York University, published in the journal The Innovation.
“The semicircular canals located in the skull between our brain and the external ear are critical for providing a sense of balance and position during human movement,” said Yinan Zhang, lead author of the study. To better explore this region, Zhang, Ni and Harrison used three-dimensional scanning technologies to create a virtual reconstruction of the bony canals of the inner ear.The scientists then compared these scans with those collected from other living and fossil apes and humans from Asia, Europe and Africa.
“Most fossil apes and their presumed ancestors have a locomotor mode intermediate between gibbons and African apes,” Ni noted. “Later, the human lineage differentiated from great apes with the acquisition of bipedalism, as sees in Australopithecus, an early human relative from Africa,” Ni continued. “The last common ancestor of apes and humans had a locomotor repertoire similar to that of Lufengpithecus, employing a combination of climbing and climbing, suspension of the forelimbs, arboreal bipedalism and terrestrial quadrupedalism” added Harrison.
According to scholars, climate change has influenced the locomotor diversification of monkeys and humans. “Colder global temperatures, associated with the accumulation of ice sheets in the Northern Hemisphere around 3.2 million years ago, correspond to an acceleration in the rate at which bone labyrinth change occurred and this may signal a rapid increase in the rate of locomotor evolution of apes and humans” concluded Harrison.