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19 May, 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… SKW 12 maxilla, from Kaszyc...
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. Swartkrans quartz cores fro...
Only 2 fossils from Swartkrans Lower Bank can be excluded from Paranthropus: an isolated molar fragment and a juvenile mandible fragment, SKX 21204. The unerupted premolars of this otherwise super fragmented specimen are interesting. SAHRIS image of SKX 21204 m...
Thomas Davies and coworkers examined enamel-dentin junction morphology in #Homonaledi and other #hominin premolars. SKX 21204 P3 morphology maps near Au. africanus and H. erectus doi.org/10.1038/s41598… Results from Davies et al. ...
The P4 morphology puts SKX 21204 into H. erectus. If this tooth is enough evidence, this would be the earliest H. erectus individual known in the fossil record, 250,000 years earlier than the Drimolen DNH 134 fossil. P4 EDJ morphology PCA from ...
Notice however that Au. sediba is not sampled in the EDJ morphology paper. All of the Swartkrans assignments to "Homo" predate the discovery of Au. sediba, and we have to re-evaluate these attributions in light of Au. sediba's Homo-like dental and mandibular morphology. Illustration of MH2 mandibl...
Most of the well-known hominins from Swartkrans Member 1 come from the unit known as the "Hanging Remnant". The age of this is more than 1.8 million years based on an overlying flowstone, but it is stratigraphically younger than the Lower Bank material.
Understanding the age of the Hanging Remnant fossils still continues: "We are working to retrieve clasts from the HR in order to date the younger part of the Member 1 talus more precisely." doi.org/10.1016/j.jhev…
These results from Swartkrans show that Drimolen Main Quarry is not the earliest P. robustus, and any differences among Swartkrans, Kromdraai, and DMQ are not simple evolution over time. doi.org/10.1038/s41559…

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More from @johnhawks

John Hawks Profile picture
19 May
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.
"Finally it must be reemphasized that all of this discussion does not apply only to body mass. With the growing interest in life-history, the potential misuse of traits such as molar eruption age, sex dimorphism, and cranial capacity is clearly on the horizon."
Read 4 tweets
John Hawks Profile picture
7 May
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.
Psychologists ran with this idea, trying to find all kinds of ways that 150 might make sense. But people are pretty variable in how they apportion their social lives. That didn't stop Silicon Valley types from encoding "Dunbar's number" into their social media worldview.
Read 6 tweets
John Hawks Profile picture
6 May
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.
Single body burial is presently widespread around the world, and this owes much to traditions rooted in Islamic, Christian, and Jewish heritage, coupled with colonial and industrial economies. Burial marks status even in geographic regions where it was not historically practiced.
Read 7 tweets
John Hawks Profile picture
9 Apr
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 Illustration of D3444/D3900 cranium from Dmanisi, Republic o
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 Illustration of La Chapelle-aux-Saints Neandertal cranium.
Some have criticized inferences about social care in these human relatives, by pointing out other primates that sometimes survive. This wild chimpanzee skull in the collection of the @goCMNH is a great example, with loss of all but one molar and premolars. Chimpanzee skull showing loss of nearly all upper premolars
Read 5 tweets
John Hawks Profile picture
8 Apr
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… Zlaty kun cranium in lateral view. From Rmoutilova et al. 20
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-…
From the beginning, it was unclear whether the skeleton and artifacts were associated. All appeared to have entered accidentally, falling from chambers above. This was not an occupation site. The human remains emerged over several excavation seasons.
Read 18 tweets
John Hawks Profile picture
20 Mar
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 Illustration of MH2 hominin mandible from Malapa, South Afri
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.
Some scientists claimed that the difference between MH1 and MH2 mandibular ramus shape must mean that one is Australopithecus and one Homo. Ritzman and coworkers (2016) examined this, finding them compatible with normal within-species variation. dx.doi.org/10.1016/j.jhev… Image showing MH1 and MH2 mandibles from lateral view to exa
Read 6 tweets

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