Excavating Fluffy Pastries and Pulling Gold Dust from the Air: Best Paleoanthropology of 2017!

2017 was not an easy year. Many of us found ourselves consistently disheartened and frustrated with the events unfolding around us–so much so that it was sometimes difficult to focus on science. Given those frustrations, how does one write a roundup post celebrating the year? By applauding scientific achievement and discovery, does this diminish the importance of recognizing the injustice of 2017? I have pondered this question often, and I feel that we can do both–celebrate science and be outraged in a useful, impactful way.

Indeed, in a year of “alternative facts” and attacks against scientific knowledge, we have an obligation to highlight evidence-based research and applaud the ways it furthers our knowledge of the world around us. So here’s a countdown of my favorite paleoanthropological discoveries of 2017:

10.  Meet Alesi. A 13 million year old ape from Kenya was put forward this year as a potential common ancestor of humans and other apes. There’s one particular aspect of Alesi that I find interesting: the specimen is that of a juvenile. This is problematic because it makes it difficult to compare it with other (adult) specimens while keeping in mind that features change as primates mature. One anthropologist alluded to this cruel game that the fossil record sometimes plays in only giving up juvenile specimens at times, stating  “this is the sort of thing that the fossil record loves to do to us.” The problem will likely take the discovery of more fossils to be resolved.

Nyanzapithecus alesi, image Fred Spoor

9. A new Denisovan. Denisovans are arguably one of the greatest mysteries in paleoanthropology. This hominin species is known by only a few tiny fragments of bone. We know they lived fairly recently in what is now Siberia, we know they were more closely related to Neanderthals than to us, and that’s about all we know. But this year, a child’s tooth was added to the mix, yielding a bit more DNA. The DNA evidence suggests Denisovans’ population size might have been very small. But really, we need some more bones to be sure.

8. Sediba‘s place in the family tree. When Australopithecus sediba first appeared, it was suggested an ancestor at the base of the genus Homo. A new study, however, challenges this idea, suggesting instead that many of the features that appear “homo-like” are the result of the fossil’s juvenile age (the type specimen was about as old as a 7th grader when it died). This challenge to sediba’s place in the family tree takes a closer look at the ways traits develop in Australopiths and reminds us that science progresses in many ways, not only with new discoveries but also with new analyses.

Australopithecus sediba, by Brett Eloff. Courtesy Prof Berger and Wits University

7. A shockingly complete Australopith, meet Little foot. An extraordinary fossil skeleton was revealed recently from South Africa, after twenty years of work excavating the bones. The skeleton is that of a 3 million-year-old Australopith, her discoverer Ron Clarke argues. Discussing the condition of the bones, Prof Clarke said it was like “excavating a fluffy pastry out of concrete” –a challenging task indeed. But where does Little foot fit in the family tree? No formal analysis has been published yet on the skeleton, so we just don’t know yet. This particular little girl might very well be number one next year, once those answers start to come out. Stay tuned.

6. When did modern humans first arrive in Southeast Asia? A new look at an old tooth has revealed a surprising fact: humans may have been in Southeast Asia as early as 70,000 years ago–over 20,000 years before scientists thought! Why is this interesting? Well, this particular Indonesian island is quite far from the location of supposed human origin (Africa), which potentially speaks to fascinating speeds of migration. This find could tell us more about ourselves and our dispersal around the world.

Little Foot, Themba Hadebe/AP

5. Hobbit’s place in the family tree. Speaking of SE Asia– how did that nagging Homo floresiensis question end up? Where did the tiny, island-dwelling hobbits come from? Who were their closest relatives? Were they descendants of Homo erectus, Australopithecus, or something else entirely? Oh. They haven’t quite landed yet at all, you say? FASCINATING. A new study came out this year refuting one hypothesis (which states they were a dwarfed version of Homo erectus). These researchers suggested instead that the hobbits descended from a hominin more primitive. But who? Scientists still don’t know, possibly a creature more similar to Homo habilis. What’s impressive about this study is its comprehensiveness, the researchers examined 133 cranial, skeletal, and dental samples from a variety of ancient and modern species for comparison.

4. Introducing Neo. This year, we met Neo, the newest member of the species Homo naledi. Neo (which means gift) was remarkably complete and was discovered in a chamber near the cache of naledi bones. Neo provides more information about naledi body size, and as I mentioned in a post at the time of the announcement, the preservation is just beautiful. Neo includes some bones of the face that are extremely fragile and usually don’t preserve. Also, it’s worth mentioning that retrieving Neo was no easy feat, it involved lying wedged between rocks for hours at a time. You can learn about Neo in the open access paper in elife.

Neo (Homo naledi), from Hawks et al, doi: 10.7554/eLife.24232.

3.  Jebel Irhoud sapiens ancestors. Decades of work at the site of Jebel Irhoud have revealed some strange, human-looking bones. While not quite Homo sapiens, these specimens might shed some light on our lineage just before we became modern–giving our species some desperately needed history. One of the biggest surprises? The site’s location. Morocco is far from African locations where scientists had been searching for sapiens ancestors (seriously–check out a map, so far). This has led some scientists to reevaluate their assumptions about where–within Africa–our evolution was occurring. PS check out this epic poem about the discovery: “Experts of the world came to here to dwell; On these mysterious species, their story to tell…”

2. The age of Homo naledi. When the strange hominins Homo naledi were announced in 2015, everyone asked: how long ago did they live? Since their discovery, scientists in South Africa have been working to answer that question. They lived approximately 200,000 years ago. That is wild to think about, particularly because naledi had very small brains and retained other primitive features. One of the implications of these dates is that it suggests Homo sapiens were not alone in South Africa in the very recent past. The article is open access on elife.

1. 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 has taken yet another giant leap forward–recovering DNA not only from the bones of extinct hominins like Neanderthals but also from the random dirt they left behind. 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. That’s crazy. “It’s a bit like discovering that you can extract gold dust from the air,” population geneticist Adam Siepel remarked–a sentiment that accurately captures the incredible nature of this find. This will certainly lead to interesting discoveries in the future. Can this technique illuminate other ancient hominin species, for example?

Matthias Meyer, fishing DNA from dirt. Max Planck Institute for Evolutionary Anthropology

BONUS (because science in 2017 was truly remarkable):

• Could Homo naledi speak? Scientists looked at naledi‘s endocast (the imprint of the brain on the skull) to learn more about the development of its parts. They found that though the brain is small, it’s organized in an advanced manner, much like modern humans. Surprisingly, naledi may have had the ability to speak, suggested by the development of part of the frontal lobe. A crazy thing to think about!
• Neanderthal DNA reveals new patterns of human migration. New analysis of a Neanderthal bone discovered almost a century ago reveals that some version of modern Homo sapiens left Africa as early as 270,000 years ago–and illuminates some other fascinating migration patterns.
• Neanderthals Were People Too. For a fascinating take on paleoanthropology, check out Jon Mooallem’s story on the ways scientific perceptions of Neanderthals have changed over time (to which I contributed a quote or two)!

Take-home messages of 2017:

• Expect the unexpected. A primitive creature like naledi living alongside Homo sapiens at 200,000 years ago?! A sapiens ancestor in Morocco?! The world of paleoanthropology is a crazy place right now, and I doubt the surprises will stop rolling in anytime soon.
• Old can be new again. 2017 reminds us that important information doesn’t always have to come from new excavations and finds–discoveries can also be made in familiar places. Many of the bones mentioned here– the Denisovan, the Neanderthal, the human from Indonesia–were discovered decades ago. By taking good care of these relics over the years, scientists can now go back and learn from them using new tools and approaches. That’s pretty cool.
• There’s still a lot to learn about the recent human past. The issue of the origins of modern humans seems to become cloudier every year. The more scientists learn, the more complicated the picture appears. Where in Africa did modern humans evolve? Who lived alongside them? Who did they interbreed with? These remain open, incredibly fascinating questions.

All in all, despite the fact that it hasn’t been an easy year to celebrate science, I have to draw hope from these incredible finds. I have to believe that innovation matters, that knowledge is still valued, and that humans as a whole will continue to be weird, creative creatures who pull DNA from dirt and throw robot birthday parties on Mars (a story for another day). Moving into 2018, I will continue to look back on history for lessons while looking forward to science for hope.

What do you all think? What did I miss, overvalue, or undervalue?! And what do you think 2018 will bring in this fascinating, ever-changing branch of science?