At the beginning of the decade that’s soon ending, I was but a third-year PhD student at UW-Madison, yet to publish my first peer-reviewed scientific paper. Lady Gaga dominated the airwaves with Poker Face & Just Dance. Avatar ruled the movie theaters. The Saints won the Super Bowl, giving their hometown a major morale boost while still recovering from Hurricane Katrina. On any given Thursday afternoon, I was likely eating cheese curds & drinking beers at the Union Terrace overlooking Lake Mendota.
Paleoanthropology from 2010-2019 was DELIGHTFUL. There were so many eyebrow-raising, remarkable, thought-provoking discoveries, it was difficult compiling this list. Rather than rank them by importance, I put them in chronological order.
2010: Neanderthal genome
Millions of people now living have Neanderthal ancestors! Including me! The technical achievement is incredible, & it’s fascinating to think that Svante Pääbo got his start with extracting DNA from a 2,400-year-old Egyptian mummy in 1985. (3.4 whole kilobases! Can you believe it?!) 25 years later, he & his colleagues unveiled the Neanderthal genome, compiled from multiple individual Neanderthals who lived throughout Eurasia as long as 70,000ish years ago. While molecular studies of Neanderthal mitochondrial DNA implied Neanderthals went extinct without contributing to living Homo sapiens, the newer, much more informative nuclear DNA analyses demonstrated inarguably that Neanderthals are part of our ancestry.
2010: Australopithecus sediba
The story of Lee Berger’s young son Matt, finding sediba while out walking with his family, is now paleoanthropological lore. The specimens are remarkably complete & well-preserved. At about 2-million-years-old, its brain was relatively small, but its jaws & teeth were also smaller. The hands were much more modern than the feet. Nearly 10 years later, I still don’t really understand how their feet & ankles worked. They’re weird.
The Denisovans lived in Siberia about 40,000 years ago. We’ve found their artifacts, & in 2010, a manual phalanx or finger bone. That’s it. You can’t diagnose a new species from a finger bone. But DNA extracted from the finger illustrated the Denisovans were genetically distinct from Neanderthals and Homo sapiens, & therefore for the first time, a branch was added to the human family tree not with fossilized bones, but with fossilized DNA. Much like how Neanderthals contributed genetic material to us, so did the Denisovans.
In 1997, Sileshi Semaw & colleagues published Oldowan tools from Gona, Ethiopia. They were remarkable because they were the oldest stone tools yet discovered at 2.5-million-years. Sonia Harmand & colleagues published Lomekwian stone tools from West Turkana, Kenya in 2015. They’re remarkable because they’re even older than the Gona tools – by nearly a million years! Dating to 3.3-million-years-old, it’s possible stone tool manufacture is a defining character of the australopithecines. I won’t be surprised if/when even older stone tools are found, & they’ll be on my ‘Top 10 of the 2020s’ list in 2029.
While there’s been some debate about whether the Ledi-Geraru jaw & teeth are best-described as Australopithecus or Homo, its discoverers assert it is Homo – and at 2.9-million-years-old, the earliest Homo. Prior to its discovery, the earliest Homo specimens were about 2.3-million-years-old. But I’m not as interested in its taxonomic assignment as I am by how its anatomy is not at all surprising given its age and location. It is an outstanding example of a transitional fossil – it’s somewhat australopithecine and somewhat hominine.
2015: Homo naledi
It’s difficult to succinctly summarize naledi! In my opinion, I think the three most important lessons from naledi are: keep exploring, paleoanthropology can be an open science, & hominins appear to have ‘endless forms most beautiful.’ The Rising Star cave system where naledi was discovered is an easy hike from other Cradle of Humankind sites, which have been excavated for decades. Homo naledi had been there the whole time, just waiting to be found. Of all the work we’ve done on naledi, I’m most proud & pleased by how inclusive & engaging the process has been. From inviting junior scholars from around the globe to be primary researchers, to open access publishing & 3D scan sharing, to the extensive outreach online and in person (from what I gather from colleagues’ CVs, we’ve given more than 200 academic and over 100 public talks total on naledi), Homo naledi has been incredibly accessible. And naledi’s mish-mash of anatomical details is so weird! Small brain in a Homo-shaped cranium. Shoulders & curved fingers of a climber, with digit lengths & metacarpals of a tool maker. A short, modern human-like big toe with longer, australopithecine-like lesser toes. I always shudder to think how any of these details might have been interpreted if they had been discovered in isolation. Fortunately, there were plenty of specimens to study!
2018: Bornean paleolithic cave art
I’m always fascinated by ancient art, in all its forms. While I study anatomy, we’re more than just what we look like, we’re also what we think. And about 40,000 years ago, humans in Borneo were thinking about animals. These cave paintings are the oldest known figurative art, featuring animals. I also like artwork about animals. I like to think these ancient Borneans were painting animals while eating them!
2018: Little Foot
While Little Foot was discovered when I was in middle school, it was only officially unveiled to the world the year I was promoted to associate professor. It’s always great to see South African paleoanthropology making headlines in the news, and I can’t wait to read the peer-reviewed papers detailing this important specimen!
2019: Australopithecine breastfeeding
Fossilized bones can tell us about extinct hominins in more ways than just what their bodies looked like & how they moved. Teeth can even tell us how our ancient ancestors grew up, & this remarkable study demonstrated australopithecines nursed their infants for about a year. Modern human breastfeeding is highly variable, but in general, human moms don’t breastfeed their infants nearly as long as great ape moms nurse theirs. In this regard, australopithecines were more like us than great apes.
2019: Homo luzonensis
There are only a handful of teeth, a couple manual & pedal phalanges (finger & toe bones), and a third metatarsal representing this hominin. My colleagues who specialize in teeth tell me luzonensis is a legit, newly-discovered species of our genus. Its third metatarsal & phalanges are…inadequate for diagnosing a new species. Teeth are the gold standard for diagnosing mammalian species, not foot bones, so for now, the species designation stands. Hopefully more specimens are found, so we can learn more about these enigmatic people!