The Most Fascinating Human Evolution Discoveries of 2013

By Kate Wong | January 1, 2014 |

Sahelanthropus tchadensis had a tiny brain, but one that had nonetheless undergone some reorganization toward the human condition. Image: Didier Descouens, via Wikimedia Commons

Wow. I’ve just spent the last couple days going through the paleoanthropology news that broke in 2013 and I must say it was a banner year. There were so many exciting new findings that bear on scientists’ understanding of just about every chapter of humanity’s seven-million-year saga—from our ancestors’ first upright steps to the peopling of the Americas. But don’t take my word for it. Check out the links below for highlights from our latest turn around the sun and see for yourself just how very far we have come.

Analysis of the shape of the braincase of seven-million-year-old Sahelanthropus tchadensis from Chad supports the claim that it is the oldest human ancestor on record.

The femur of Orrorin tugenensis, a putative human ancestor that lived six million years ago in Kenya, has a shape that is intermediate between that of fossil apes and early members of the human lineage—a finding that confirms previous claims that the creature walked upright.

Tiny, rarely preserved middle-ear bones from two of our ancient relatives that lived millions of years ago exhibit modern features, which may indicate an early shift in hearing ability.

The latest round of studies of Australopithecus sediba, a nearly two-million-year-old relative of ours from South Africa, reveals a previously unknown form of upright walking and decidedly humanlike jaws and teeth. But is it the ancestor of our genus, Homo? Not so fast.

Our ability to throw projectiles with speed and accuracy originated around two million years ago in Homo erectus thanks to key shoulder adaptations, a study of college athletes suggests. This new throwing arm helped make our ancestors deadly predators. Indeed, early Homo became so good at hunting large game that they may have driven many of Africa’s large carnivores to extinction by outcompeting them.

Spectacular skull from the site of Dmanisi in Georgia is the fifth skull to emerge from the site, which dates to 1.77 million years ago. The specimens are quite diverse in size and shape, yet they all come from the same time and place, and thus surely belong to the same species. The discovery team argues that the variation seen in this one group suggests that several early human species that scientists have named may in fact belong to a single, variable species. Not everyone agrees. Either way, some of the variation evident in the lower jaw bones from Dmanisi may be the result of overuse of toothpicks.

A hand bone dating to nearly 1.5 million years ago, probably from H. erectus, shows that a key feature related to the dexterity and strength necessary for making and wielding complex tools evolved half a million years earlier than previously thought.

First partial skeleton of Paranthropus boisei, a 1.34-million-year-old specimen from Tanzania’s Olduvai Gorge, indicates that this species had an extremely robust build and spent at least some of its time in the trees.

Researchers unearthed a treasure trove of fossils belonging to an as-yet-unidentified human relative from a cave in South Africa’s Cradle of Humankind—and invited the world to follow the adventure as it unfolded (not the usual way of doing things in paleoanthropology, which is notoriously secretive).

DNA from a 400,000-year-old fossil from Spain—the oldest human DNA yet by a long shot—unexpectedly resembles DNA from the mysterious Denisovan people who lived in Siberia 80,000 years ago.

Stone-tipped javelins from Ethiopia date to more than 279,000 years ago, making them nearly 200,000 years older than the previous record holders. Experts thought that H. sapiens was the first species to invent composite projectiles, but the new finds pre-date the origin of our kind and thus must be the handiwork of another species. It’s one more wrinkle in the surprisingly complex story of the evolution of human creativity.

The first high-quality genome of a Neandertal—a female who lived in Siberia around 50,000 years ago–shows that her parents were as closely related as half siblings and that her recent ancestors mated with close relatives, too. Comparison of her genome with genomes of other extinct humans suggests that both Neandertals and an unknown human species interbred with the mysterious Denisovans from Siberia—yet more evidence of interspecies boot-knocking among our ancestors.

Neandertals had a good year. A French find revealed they used special bone tools called lissoirs to make animal hides smooth and supple just as modern-day leather workers do. They also seem to have independently invented string (one of the all-time great innovations) by 90,000 years ago, free from the influence of anatomically modern H. sapiens. In addition, analysis of a cave in Italy showed that Neandertals were neatniks, organizing their homes to create spaces dedicated to specific tasks (a behavior previously ascribed exclusively to modern humans). And re-assessment of a site in France demonstrated that Neandertals intentionally buried their dead. Time to stop using their name as a pejorative? Hell yeah.

Additional wrist bones of the wee human “hobbits” that lived in Indonesia as recently as 17,000 years ago bolster the case for the remains representing a distinct species, H. floresiensis, and not diseased modern humans as critics have claimed. On a sad note, archaeologist Mike Morwood, co-discoverer of our little hobbit cousins, passed away.

Conventional wisdom holds that Native Americans are descended from East Asians, but the genome of a Siberian boy who lived 24,000 years ago suggests that about a third of their ancestry comes from Europe.

About the Author: Kate Wong is an editor and writer at Scientific American covering paleontology, archaeology and life sciences. Follow on Twitter @katewong.

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