I'm a paleoanthropologist. I explore human fossils and genomes to understand where we came from and what we share with our ancestors.
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May 17, 2023 • 5 tweets • 2 min read
Quite like the new paper by my @UWMadison colleague @apragsdale. Fun to see lots of people newly discovering these ideas about metapopulation models! A couple of notes: nature.com/articles/s4158…
An implication of this population model is that the structure of our species, Homo sapiens, began to emerge several hundred thousand years earlier than the dispersal that led to Neandertal and Denisovan populations.
Mar 18, 2022 • 7 tweets • 3 min read
So this seems very unpopular for some reason, but humans DID evolve from apes. We did not evolve from chimpanzees, gorillas, or any other living apes. They are our cousins. Our close fossil relatives were like living great apes in many ways and more like humans in others.
Today's great apes, including chimpanzees and bonobos, two species of gorillas, and three species of orangutans, are a small surviving remnant of the diversity of apes that once existed. Each evolved in ways that helped them survive, just as our ancestors did.
Dec 8, 2021 • 5 tweets • 2 min read
Some discussion in comments last week in @ScienceMagazine about "paleodemes" with a short defense of the value of the concept. I think the paleodeme concept has most of the problems of paleo species concepts with none of their benefits. science.org/doi/10.1126/sc…
The person probably most responsible for the paleodeme concept in human origins is Clark Howell, whose 1999 paper "Paleo-Demes, Species Clades, and Extinctions in the Pleistocene Hominin Record" defined (although it did not first introduce) the concept. journals.uchicago.edu/doi/abs/10.108…
Aug 13, 2021 • 9 tweets • 2 min read
Interesting paper on cutmark evidence from Olduvai, further substantiating early access to animal carcasses by tool-wielding Early Pleistocene hominins. @SciReportsnature.com/articles/s4159…
The paper's discussion raises lots of reasons why the anatomy of early Homo supports the idea that they were competent hunters. On this I don't disagree, but I think that focusing on "early Homo" here is misleading for several reasons.
Jun 25, 2021 • 13 tweets • 5 min read
So, Homo longi. It's such a good name. Dragon people. And an amazing skull discovery. Adds to our knowledge of the Middle Pleistocene in China. But it's sad that the name is not going to stay. cell.com/the-innovation…
The boring reason why we can't use the Homo longi name is technical. The research puts the Harbin skull together with the Dali skull, and Xinzhi Wu gave that the name Homo sapiens daliensis more than 40 years ago. So IF there's a species, it has to be H. daliensis.
Jun 24, 2021 • 11 tweets • 4 min read
The new report of fossil material from Nesher Ramla, Israel, claims a "previously unknown archaic Homo population" some 140,000 years ago. It's a big claim in an area where most scientists have thought that early modern humans and Neandertals interacted. science.sciencemag.org/content/372/65…
Looking at the morphology of the mandible NR-2, it falls within the variation of fossils attributed to Neandertals, and is similar to Krapina, which is around the same age, and Sima, which are early Neandertals. This seems like a basic early Neandertal jaw.
Jun 23, 2021 • 8 tweets • 4 min read
Today, I'm reflecting on how this reporter was betrayed by her @nytimes editors. The reporting turned up so many newsworthy ledes, and instead they let it tailspin into a tuna Zoomer fluff story that spreads basic science misinformation. nytimes.com/2021/06/19/sty…@nytimes For instance, "a handful" of commercial food testing labs refused to take the @nytimes samples. They all said (accurately!!) that the technology wouldn't give an answer. Why is this not the lede in a story that is really about the challenges in sourcing food ingredients?
May 19, 2021 • 4 tweets • 1 min read
Classic paper: "Biology and Body Size in Human Evolution: Statistical Inference Misapplied" Richard Smith (1996, Current Anthropology) works through examples to show how mistaken ideas about extinct species can arise through estimation of body mass. doi.org/10.1086/204505
"[A]s of today, many inferences about fossil hominids are being made on the basis of body mass alone, and the range of uncertainty is being mostly ignored." This problem remains 25 years later.
May 19, 2021 • 9 tweets • 4 min read
"A new dating program using the isochron method for burial dating has established an absolute age of 2.22 ± 0.09 Ma for a large portion of the Lower Bank, containing the earliest Oldowan stone tools and fossils of Paranthropus robustus in South Africa." doi.org/10.1016/j.jhev…
If this date is accurate, it places a good Oldowan assemblage into a temporal context where it's not clear Homo was present at all. These are Paranthropus or Australopithecus tools.
May 7, 2021 • 6 tweets • 2 min read
Anthropologists of the 1990s often did pygmy marmoset-to-gorilla regressions across primates to "predict" all kinds of things about extinct hominins. We don't teach this anymore, but the resulting myths are tenacious. One of those is "Dunbar's number". royalsocietypublishing.org/doi/10.1098/rs…
The idea was that brain size limits the number of social relationships you can have. Dunbar took a cross-primate regression of group size and brain size, and plotted humans. He surmised that the human brain should max out at around 150 social relationships. This isn't right.
May 6, 2021 • 7 tweets • 2 min read
I'm concerned about the narrative I've been seeing about burial. All current and recent cultures have had some form of mortuary practice. To dig a hole, place a single intact body, and cover it up is only one pathway among a wide spectrum.
There is nothing about this burial pathway that is more "human", or more demonstrative of "symbolic culture", or "higher" than others. Communal burials, catacombs, creches, skull curation, sky burial, ritual cannibalism, and mummification are all human.
Apr 21, 2021 • 5 tweets • 1 min read
I saw a press release for this paper, and thought, whoa, those are some provocative claims. Then I read it. It is hard to describe how bad it is. "Evolution of genetic networks for human creativity" doi.org/10.1038/s41380…
The paper almost could be a case study in what happens when you ignore every caution that has been raised during the last 10 years about interpreting GWAS and PRS beyond the study sample.
Apr 9, 2021 • 5 tweets • 3 min read
A hint of the social behavior of early Homo erectus comes from the earliest known #hominin to survive with near total loss of teeth, 1.8 million years ago. Some wild primates also survive years with little functional dentition. #paleoanthropology#FossilFriday
For years, anthropologists have looked at the survival of older people with tooth loss as a possible indication of social caring, empathy, and value of tradition and knowledge to social groups—once with Neandertals, more recently with H. erectus. #paleoanthropology
Apr 8, 2021 • 18 tweets • 5 min read
Out of yesterday's Neandertal ancestry-oriented papers, I am more focused on the Zlatý kůň analysis. The history of thinking about this partial skeleton and the way this paper changes that thinking has much to reveal about this moment in the science. doi.org/10.1038/s41559…
The Zlatý kůň skeleton was discovered in 1950 when a nearby limestone quarry blasted an opening into a previously unknown cave system. The skeletal remains and many artifacts were within a debris cone from a chimney going higher into the cave. doi.org/10.1007/978-1-…
Mar 20, 2021 • 6 tweets • 3 min read
The MH2 #hominin mandible is still being built, fragment by fragment, as pieces are recovered from Malapa and prepared in the lab. The skull of this adult Australopithecus sediba individual may be found within the breccia as well. #paleoanthropology
If you're following this series of illustrations, you may recognize that MH2 is my first repeat, as I earlier featured the MH2 pelvis. The Malapa skeletons are amazing examples of discovery, as each piece emerges from the site, it allows us to test new hypotheses.
Mar 20, 2021 • 4 tweets • 1 min read
Some say MSA/Middle Paleolithic hominins used ochre for sun protection, blocking any conclusions about marking or other symbolic uses. I say traditions of processing and using mineral pigments for sun protection are more complex and less universal than cosmetic uses.
Some archaeologists have focused on cosmetic uses of pigments, but it remains much more common to see ochre and other pigments framed in terms of "symbolic marking" or "marking".
Feb 19, 2021 • 9 tweets • 3 min read
So, I've started tracking down the citations in this Magnetodeth paper. It will be a surprise to no one that the papers on genetic bottlenecks do not support the 42,000-year-ago event that the new paper says they do.
For example, the paper claims that thylacines underwent a bottleneck 42,000 years ago, citing Lauren White et al. 2018 doi.org/10.1111/jbi.13… That paper actually says 20,400 years.
Feb 10, 2021 • 4 tweets • 2 min read
This quote from Anders Bergström @pontus_skoglund@ChrisStringer65@DrEleanorScerri@MatejaHajdi carries an essential message: Genomic data today are not good enough to tell us how and when today's populations of humans started to emerge. doi.org/10.1038/s41586…
One way of casting this lack of knowledge is to say maybe there was no "origin", that we are looking backward through a cloudy lens at a gradual mixing process that never had a beginning. This idea comports with what we know about continued Neandertal-African mixing.
Jan 28, 2021 • 7 tweets • 2 min read
Lactase persistence and dairying on the surface seem to be a simple and compelling example of gene-culture coevolution in humans. And yet there are patterns that confound the simplistic story. I appreciate that @Maddy_Bleasdale et al discuss some of those. nature.com/articles/s4146…
Several aspects of lactase persistence genetics are not being covered well by press accounts of this paper. Journalists have gone with a pretty simple "counterintuitive lede", i.e., people were drinking milk before lactase persistence mutations were common.
Jan 27, 2021 • 8 tweets • 2 min read
A lot of problems in science come down to whether larger amounts of noisy data are better or worse than smaller amounts of high-precision data. Of course, in paleoanthropology we usually are faced with small amounts of noisy data.
Our problems are that paleoanthropologists make up for shortfalls in data by carting in models and assumptions. These take on a life of their own, so much that even new discoveries that provide high-precision data cannot make a dent in most people's research direction.
Oct 6, 2020 • 5 tweets • 1 min read
Most people have around a chromosome's worth of DNA from Neandertals, spread in small pieces across all 46 chromosomes.
Or, if you're of male sex, 45 out of 46 of them.