The future is never going to look quite like we imagined. We might envision flying saucers and colonies on Mars while experiencing smaller futuristic advances like cordless earphones. Although we aren’t all zipping around the solar system on space shuttles (yet), I would argue that we are, in fact, living in the future—and I have an end-of-the-decade listicle to prove it.
The closing of 2019 provides us with a unique, precious moment of reflection on the future in which we are now living–a chance to reflect on an entire decade of discovery, debate, and discussion about our origins. For this post, then, let’s look back on the discoveries that were announced from 2010-2019, reliving them fossil by fossil and seeing what lessons we can draw from these beautiful bits of bone.
This was an absolutely fascinating 10 years, which means that narrowing down the entire decade to 10 discoveries is nothing more than a fun exercise in futility. With that in mind, I have one quick caveat: this list is somewhat skewed towards the latter part of the decade. There are two reasons for this. 1) Memory is fallible and 2) this particular author, circa 2010, was merely an underage college student/waitress who was only just beginning to be interested in the rapidly-advancing field of paleoanthropology. So let’s dive right into my favorite discoveries from the last decade:
10. Burtele foot. The 2012 announcement of Australopith foot bones from the Afar region of Ethiopia came with quite a surprise: an opposable toe. The 3.4 million-year-old foot looks different from the infamous Australopiths that lived at the same time, Australopithecus afarensis. The fossils are made even more intriguing by the fact that the Afar was also home to Lucy’s species (A afarensis). Did evolution experiment with different kinds of locomotor patterns in different species?
9. Australopithecus anamensis gets a face. The slightly-more-primitive-than-Lucy hominin species, A. anamensis, received a face this decade, with the discovery of a fairly complete skull in the Afar. The face shares some characteristics with its potential descendant, afarensis. Also, it’s absolutely beautiful.
8. Dmanisi skull 5. Though this spectacular skull from Dmanisi, Georgia was discovered a few years prior, we learned about the fifth skull from the site in the early 2010s. The fossil, which dates to 1.77 million years ago, revealed that a remarkable amount of diversity exists in the size and shape of Dmanisi specimens—despite the fact that they came from the same time and place. There is still some debate about what this diversity means, exactly, but I look forward to seeing what else this site has to reveal.
7. Sima DNA. In 2016, some 430,000-year-old fossils from the wonderful Sima de los Huesos site (Pit of Bones) in Spain have yielded part of their nuclear genome. The fact that scientists are sequencing genomes of creatures who lived almost half a million years ago is truly impressive. The Sima DNA suggests that the hominins are likely the ancestors of Neandertals, which pushes back in time when we should be looking for the common ancestor of Neandertals and humans. Paleoanthropologist Maria Martinón-Torres said the find is “like science fiction” and I couldn’t agree more. “We are really reaching the limits of what is possible” in DNA research, a specialist added.
6. Australopithecus sediba. An accidental discovery by a paleoanthropologist’s son revealed a new species of Southern Ape in the early part of the decade. The find, which consisted of two fairly complete skeletons and their skulls (!), revealed a mixture of Australopith features in addition to more derived features. On the skull, for example, A. sediba displays big brow ridges but also more modern, small premolars and molars, characteristics that are more similar to Homo. While the exact place of the 2-million-year-old A. sediba in the hominin family tree is still debated, its completeness unquestionably makes it one of the most fascinating finds of the decade.
5. Early Homo from Ledi-Geraru. One small fossil helped fill a pretty big gap this decade: a partial jaw from Ethiopia. The discovery team suggested that this 2.8 million-year-old specimen is transitional between Australopiths and the genus Homo, moving the later genus back almost half a million years in time. The Ledi jaw has traits we see in Australopithecines such as a lack of a defined chin. Also, the fossil has traits that look more human-like, as we see in later Homo, such as slim molars, symmetrical premolars, and an evenly proportioned jaw. The fossil is an “excellent case of a transitional fossil in a critical time period in human evolution,” the time period in which out genus emerged.
4. Tiny island hominins. If the biggest question mark of a couple of decades ago was the surprising diminutive hominin named Homo floresiensis, then we received a couple of glimmers of an answer about that mystery this decade. Two examples of equally tiny hominins (with interesting mosaics of primitive and derived features) emerged—and I have lumped their fragmentary, Southeast Asian island remains together for fourth place. One discovery was from Mata Menge, a site on the same island that revealed H. floresiensis. Although this find was extremely partial—consisting of only a partial jaw and a few teeth—it does potentially point to a relative of H. floresiensis. An additional fascinating discovery from the Philippines was determined to be a separate species from the infamous hobbits—but one that suggests something interesting was happening on these islands.
3. DNA from cave dirt. Not long ago, scientists weren’t even sure if DNA could survive in a bone after an organism died. Fast forward to 2017 and the field of ancient DNA took yet another giant leap forward: recovering DNA not only from the bones of extinct hominins but also from the random dirt from the areas in which they lived. Scientists identified traces of Neandertals and Denisovans in cave dirt this year, finding evidence of their presence even without bones. Let me repeat, scientists discovered DNA without discovering bones. They pulled genetic material from the bits hominins leave behind in caves—sweat, hair, waste. “It’s a bit like discovering that you can extract gold dust from the air,” geneticist Adam Siepel remarked.
2. Homo naledi. Without a doubt, this discovery had to come high on the list. It is, after all, the largest cache of hominin fossils in Africa. A team of cavers and excavators recovered more than 1,500 fossil bones of this new hominin species in a matter of weeks, bones that belonged to at least 15 individuals and ranged widely in age. In the years since the initial, massive discovery was announced (2015), we have met new individuals, like the amazing Neo, and we’ve also come to learn that this fascinating species lived as recently as 250,000 years ago.
- Denisovans. Coming in at #1 is the mysterious, “unknown hominin from Siberia.” Looking back on the last decade of Denisovan research is truly an exercise in awe. If you had told a paleoanthropologist this saga in 2009, I doubt anyone would have believed you. In 2010, we first learned of the new hominin in a manner unlike ever before: through its genome. A tiny finger bone from a cave revealed the genome of a relative of humans and Neanderthals that was clearly distinct. Yet, nothing was known about the species morphologically. The already-inconceivable story only got weirder (and more fascinating) from there. Denisovan bits and pieces continued to pop up, and though they were rarely very diagnostic, their DNA continued to fill in a picture of this mysterious group.
Then, in 2018, the plot thickened: we met Denny, a specimen that makes me feel like we are living inside a science fiction novel written about the future. Denny is an incredible sliver of bone whose DNA revealed that she a father was a Denisovan and a mother was a Neanderthal. To find a first-generation person of mixed ancestry was, as population geneticist Pontus Skoglund put it, “absolutely extraordinary. It’s really great science coupled with a little bit of luck.” Denny has been called “the most fascinating person who’s ever had their genome sequenced.” What more does the Denisova cave (and many other sites mentioned in this post) have in store for us, one can’t help but wonder…
Summary and lessons. Of course, in a decade filled with so much incredible science, these rankings are arbitrary. What’s cool is that they all move us closer to understanding our shared human origins. I think they all feed into a few themes, which can be summed up in lessons of the decade.
- Beware of simple definitions or explanations. From East Africa to South Africa to Asia, “new studies leave us with an even more complex picture of early humans than we thought, and they challenge us to consider the very definition of what it is to be human,” as Chris Stringer put it. “Are we defined by our small teeth and jaws, our large brain, our long legs, tool-making, or some combination of these traits?” This decade challenged us to reconsider much of what we thought we knew.
- Old evidence is worth a new look. Though I have highlighted new finds in this post, this decade also reminds us that important information doesn’t always come from new excavations. Discoveries can be made in familiar places. By taking care of these relics over the years while developing new techniques for analysis, scientists can go back and learn from them using new tools and approaches. That’s pretty cool.
- We were not alone. From new genetic evidence to new hominin finds, one thing we’ve learned over the last couple of decades is the picture of recent human evolution was messy, bushy, and complex. As Josh Akey recently said: “If we look around the world today, we are really the only hominin game in town. People assume that’s the way it must have always been. In fact, the world was a much more interesting place not that long ago.”
- Nothing is impossible. If scientists can discover new hominins from finger bones, get DNA from cave dirt, and find rich new cave chambers full of fossils located in well-explored areas, then anything is possible, it seems to me.
Cheers to an incredible decade of discovery; it’s difficult to imagine a more exciting time for the science of human origins. A huge thank you to all the explorers who roam underground caves, comb the desert, and dig in the dirt. Also thank you to those in the labs–writing grants, editing papers, and doing everything necessary to make this possible. As we embark on a new decade, the only thing I’m sure of is that evidence will continue to accumulate to show us just how interesting the world was not that long ago.
Now I’d like to hear from you! Tell me what you think–did I miss anything major? What are your favorites from the decade? What are you looking forward to most in the 2020s? There will certainly be more to come so, as always, stay tuned.