Ancient Human Ancestors Had to Deal with Climbing Toddlers

[Judi Lynn]

By Kimberly Hickok, Staff Writer | July 4, 2018 02:00pm ET

More than 3 million years ago, our adult human ancestors were walking on two feet and didn't have the option of a fashionable baby sling to carry their kids around in. Instead, Australopithecus afarensis toddlers had a special grasping toe that helped them hold on to their mothers and escape into the trees, reports a study published today (July 4) in Science Advances.

The evidence comes from DIK-1-1 — a relatively complete 3.3 million-year-old skeleton of a 2.5- to 3-year-old female Australopithecus afarensis discovered in Dikika, Ethiopia. The skeleton, nicknamed Selam — after the word for peace in Ethiopia's official language of Amharic – includes the oldest and most complete foot bones of this species ever found. [Image Gallery: 3-Year-Old Human Ancestor 'Selam' Revealed]

"It's a very exciting discovery," said Will Harcourt-Smith, a paleontologist at the American Museum of Natural History in New York, who was not involved in the study and was a reviewer of the paper. "It's really special and really allows us to learn something more about this creature."

Human-like, with a chimp-like toe
Zeresenay Alemseged, a paleoanthropologist at the University of Chicago, discovered Selam's preserved skeleton in 2000. The skeleton was initially dubbed "Lucy's baby" because of its close proximity to the adult female A. afarensis fossil named Lucy, found in 1974. But Selam actually died more than 100,000 years before Lucy was even alive.

More:
https://www.livescience.com/62984-hominin-foot-fossil.html

[greyl]

1. But doesn't that go without saying? Article more substantial than headline, ... nt

[cyclonefence]

2. Does this mean that modern humans' foot structure is

more recently evolved than other parts of the body? I find this fascinating. It sounds to me--a total ignoramus about evolution--as if we held on to what I would call ape-like physical characteristics where we needed them longer, in this case to be able to shelter in trees. I guess there's probably a sub-speciality of anthropology dealing with evolution of the human foot? If I were 60 years younger I might want to study this--right now I'm happy for anything anyone tells me about anything.

[Loki Liesmith]

3. No, not necessarily

Just because one ancestral holotype and its contemporaries had a specialized toe doesn’t mean all breeds of ancestral hominids did. It’s possible that the chimp like toe was a reactivated trait that had been genetically inactivated and then re-emerged. Or it could have just been a newly evolved trait.