New research shines light on hominoid precursor
11 Dec 2017 by Evoluted New Media
Research suggests that the last common ancestor of humans and apes was smaller than previously thought.
Research suggests that the last common ancestor of humans and apes was smaller than previously thought. The researchers from the American Museum of Natural History believe that it was actually the size of a gibbon. It probably weighed about 12 pounds, in contradiction of the widely-agreed chimpanzee-like hominoid ancestor theory.
Mark Grabowski, lead author of the study who carried out the work while a postdoctoral fellow at the Museum, said: “Body size directly affects how an animal relates to its environment, and no trait has a wider range of biological implications. However, little is known about the size of the last common ancestor of humans and all living apes. This omission is startling because numerous paleobiological hypotheses depend on body size estimates at and prior to the root of our lineage.”
Among living primates, humans are most closely related to apes, which include the lesser apes (gibbons) and great apes (chimpanzees, gorillas and orangutans). Classed as hominoids, they emerged and diversified during the Miocene Era, between 23 million to 5 million years ago. But, because fossils are so scarce, researchers do not have a complete idea of what the last common ancestors of living apes and humans looked like or where they originated.
To understand better how body mass evolution occurred, Grabowski along with co-author William Jungers, compared body size data from modern primates (including humans), to recently published estimates for fossil hominins. This led the researchers to their conclusions of a 12 pound hominoid.
As part of their findings, the researchers also imply that suspensory locomotion – overhand hanging and swinging – arose for other reasons than the primate being too large to walk on top of branches. The scientists believe that the hominid ancestor was already suspensory to a degree and a larger body evolved at a late time.
Grabowski said: “There appears to be a decrease in overall body size within our lineage, rather than size simply staying the same or getting bigger with time, which goes against how we generally think about evolution.”
The article was published in Nature Communications.
