Increasing evidence for both taxonomic diversity and early stone manufacture during the Pliocene highlights the importance of the hominin fossil record from this epoch in eastern Africa. Here, we describe dental remains from Lomekwi (West Turkana, Kenya), which date from between 3.2 and 3.5 Ma. The sample was collected between 1982 and 2009 and includes five gnathic specimens and a total of 67 teeth (mostly isolated permanent postcanine teeth). Standard linear dimensions indicate that, although the Lomekwi teeth are relatively small, there is broad overlap in size with contemporary Australopithecus afarensis and Australopithecus deyiremeda specimens at most tooth positions. However, some dental characters differentiate this sample from these species, including a relatively large P4 and M3 compared with the M1, a high incidence of well-developed protostylids, and specific accessory molar cuspules. Owing to a lack of well-preserved tooth crowns (and the complete absence of mandibular teeth) in the holotype and paratype of Kenyanthropus platyops, and limited comparable gnathic morphology in the new specimens, it cannot be determined whether these Lomekwi specimens should be attributed to this species. Attribution of these specimens is further complicated by a lack of certainty about position along the tooth row of many of the molar specimens. More comprehensive shape analyses of the external and internal morphology of these specimens, and additional fossil finds, would facilitate the taxonomic attribution of specimens in this taxonomically diverse period of human evolution.
Alan Cyril Walker (born August 23, 1938) died on November 20, 2017, of pancreatic cancer. He was a world-renowned paleoanthropologist and the recipient of numerous awards for his extraordinary scientific achievements, including a “genius” award from the John D. and Catherine T. MacArthur Foundation, and lifetime awards such as the Charles R. Darwin Lifetime Achievement Award from the American Association of Physical Anthropologists and the Leighton Wilkie prize of the Center for Research into the Anthropological Foundations of Technology (CRAFT) and the Stone Age Institute, Indiana University, and the International Fondation Fyssen Prize in Paris. He was one of the only scholars in the world elected to the Royal Academy (U.K.) as well as the United States National Academy of Sciences and the American Academy of Arts and Sciences.
Dr. Walker was born in Leicester, England, the second of four sons of Cyril Walker, a carpenter, and Edith Tidd Walker, a housewife. He was preceded in death by his parents, his first wife Patricia Nicholson, and a younger brother, Gerald Walker. He is survived and mourned by his elder brother, J. Trevor Walker and his younger brother Michael D. Walker, both of whom livie in England, his loving second wife of 42 years, anthropologist and author Pat Shipman, of Moncure, N.C. , his son Simon B. Walker, and his son’s wife Shellene Wellnitz Walker, and his granddaughters Bryn and Meghan Walker of Morrisville, N. C. In addition, he is remembered fondly by many of his former students and colleagues in several countries.
Alan Walker earned an undergraduate degree with honors in the Natural Sciences (Geology, Zoology, Mineralogy, Petrology, and Palaeontology). Following his childhood fascination with animals and fossils, Walker obtained a grant to attend the University of London, earning a Ph.D. in Anatomy and Palaeontology under the mentorship of John Napier. His thesis topic was a study of the functional anatomy and behavior of living and fossil lemurs of Madagascar. His work had a major influence on the field, emphasizing deducing the behaviors of extinct species from living ones to paleontology. He later received an honorary D.Sc. from the University of Chicago.
For much of his career, Dr. Walker was a brilliant teacher of human gross anatomy, training thousands of future physicians. Institutions where he worked included the Royal Free Hospital, School of Medicine, London (19165), Makerere University College, Kampala, Uganda (1965-1969), the University of Nairobi Medical School, Kenya (1969-1974), Harvard Medical School (1973-1978), and The Johns Hopkins University School of Medicine (1978-1995). In 1995 he moved to The Pennsylvania State University to teach anatomy and biology to undergraduate and graduate students, retiring in 2010 as an Evan Pugh Professor of Anthropology & Biology.
Throughout his academic career, Alan Walker was known for his kindness and generosity to students, for the tremendous breadth of his interests and knowledge, and for pioneering new approaches to evolutionary problems. He was instrumental in developing the field of dental microwear to deduce diets of extinct species and was among the first to the study of the structure of the inner ear of fossils to understand their patterns of locomotion and movement of extinct animals.
He was also known for his collaborations in finding fossils with Richard and Meave Leakey in Kenya. One of their most important discoveries was the finding, excavation, and analysis of the most complete ever skeleton of Homo erectus from Nariokotome, Kenya. This skeleton revealed the startlingly tall and lanky stature of a youngster of the species that first migrated out of the African continent. His research also had a major impact on the study of fossil apes, following his discovery of thousands of bones of several extinct apelike creatures on Rusinga and Mfwangano Islands in Lake Victoria, Kenya.
In accordance with his wishes, there will be no funeral or memorial services. Condolences may be sent to his wife, Dr. Pat Shipman, at 3140 Chatham Church Road., Moncure NC 27559 or (firstname.lastname@example.org). In lieu of flowers, friends and family in the U.S. may send donations to St John’s College, Cambridge, at www.cantab.org/giveonline or, in the U.K., to https://johnian.joh.cam.ac.uk/giving/donate.
New discoveries of fossilised hominin remains have to varying degrees helped to shape our ever-morphing interpretation of hominin evolution. Homo naledi is a case in point.
Though many worker in the field of palaeoanthropology were disappointed with the confirmed Middle Pleistocene age of the Dinaledi remains, this news nevertheless fills a void in our understanding of Middle Pleistocene evolution.
H. naledi confirms what we have known since the astonishing discovery of Homo floresiensis, namely that small brained hominins continued to thrive in some part of the planet right up to recent times. H. naledi can now join Homo floresiensis in the small brain Middle to Late Pleistocene club.
Palaeoanthropologist can now exercise a high level of skepticism on dating hominin fossilised remains using morphological stucture and statistics. In 2015, palaeoanthropologist John Francis Thackeray concluded Homo naledi to be over 1.5 Ma, while Mana Dembo and her colleagues concluded an age of 930,000 years of age for the Rising Star remains. Though Dembo et al were closer to actual age of the remains, they were still nearly 600,000 years off.
Finally, H. naledi continues to confirm what we have known since the announcement of Australopithecus sediba that hominin evolution features an ever changing mosasicism. With Australopithecine-like shoulders and cranium, while the lower limbs and foot appears more derived.
An anonymous doctoral student associated with the Cerutti Mastodon research addresses critics on Reddit as follows:
First off, my qualifications: My current advisor is the third author on this paper and I worked under (and collaborated with) the second author when I worked at the San Diego Natural History Museum (in fact, I re-prepared some of the material in this paper about 6 years ago). Furthermore, I am a doctoral student in the final months (hopefully) of my PhD. My dissertation work has been on proboscideans (elephants and their relatives), but I have also done a fair amount of work on cetaceans (whales) and other vertebrates.
As far as the dating methods go, this site was dated using multiple types of absolute dating methods, which all resulted in a very similar age. However, the Uranium-series dating (not to be confused with radiocarbon dating, which could not give you an accurate age this old) that was used here got results with a very high confidence. In fact there is essentially no evidence of alteration that might lead to an older date (which really would not be common anyways). The dates recovered are almost unimpeachable (and I don’t say that lightly). I would be very surprised if a geochronologist or any other expert had a major problems with the dates themselves (in fact a geochronologist was a reviewer for this paper for just this reason). Also, to the people that are saying that it is perhaps time to reassess our methods of isotopic dating in general, I strongly suggest you spend more time researching and trying to understand these methods before you make a claim like this…
One other misconception that I keep seeing here are peoples’ interpretation of what is meant by “human” in this paper. “Human” is meant here in the sense of a species of the genus Homo, not necessarily Homo sapiens specifically. In fact, because of the old age it seems fairly unlikely that this would be the modern species of human rather than some other [unknown] species.
I’m sure there will be other questions or comments here throughout the next day or so, and I will try to check in from time to time and update this post. I’m also happy to answer any questions that I can (to the best of my knowledge).
Edit 1: To the folks wondering if this site could have been scavenged by humans (as opposed to hunted), I would say that, that is absolutely possible. In fact there is really no evidence one way or another to argue for hunting over scavenging at this site, and I don’t believe that this paper takes a stance on this either. In fact, I would say that the argument of hunting vs scavenging in association with this mastodon is somewhat irrelevant. What is important is that this extremely old site (relatively speaking, anyways) has fairly clear association with ancient human activity.
Edit 2: Several people have pointed out that the article discusses a lack of evidence of meat stripping on the specimen. This does suggest scavenging, as it likely means the soft tissue was at least somewhat rotted and not usable.
Edit 3: Many people are suggesting that this animal could have been scavenged or had its bones modified many thousands of years after its death (i.e., implying the tools are much younger than the mastodon). To that point 1) the type of breakage seen on these bones is indicative of damage while the bone was still fresh. Fresh bone (sometimes called “green bone”) breaks in a very different “spiral pattern” than older dried out bone; and 2) you have to remember that the sediments that the tools and mastodon are found in represent the context in which they were buried. Therefore since these materials were all found within the same layer they must have been buried at the same time. It is possible that ancient humans exhumed old bones (though I know of no actual evidence of this), but we would see telltale signs of disturbance to the sediment (which was not observed here).
In other words, I don’t think that arguments about this site will come down to whether the material is associated and coeval, but whether folks think that these artifacts are indeed stone tools. Those people who do not agree with this identification will then have to reconcile the crazy taphonomy at this site and attribute it to some other natural process (which will be no small feat, IMHO).
Edit 4: For the people asking why we don’t have any evidence of humans (or human remains) in North America in the time between the age of this site and more generally accepted dates:
First off, I would just like to note that we are almost certainly not talking about a direct lineage of humans between the time of this site and those of Clovis times (in fact, as I’ve stated above, we are likely not even talking about the same species). This was likely a very small population of humans that made it to North America that probably died out long before the modern species of human ever made it over. In that sense, there isn’t necessarily a gap of time to “bridge”.
As for why potential sites might not be preserved: There are a couple of reasons that you might not have evidence of humans found from this time. First off, you may not have rocks of the right age readily exposed in the region where the individuals were living (which is somewhat the case on the west coast, as far as I am aware). Second, the individuals could be living in an environment that is not conducive to preserving fossils (e.g., organisms that live in montane environments tend to not preserve in the fossil record because sediments are not being deposited in those regions). Third, getting preserved in the fossil record (in general) is very rare, and if your study organism has a very small population size or is short lived (as we would expect in the case here) then you have a very very low probability of being preserved (let alone found and collected). Finally, even if these scenarios aren’t the case, there is the possibility that scientists have just been looking in the wrong strata, region, or age.
People are fascinated by the use of forensic science to solve crimes. Any science can be forensic when used in the criminal and civil justice system – biology, genetics and chemistry have been applied in this way. Now something rather special is happening: the scientific skill sets developed while investigating crime scenes, homicides and mass fatalities are being put to use outside the courtroom. Forensic anthropology is one field where this is happening.
Loosely defined, forensic anthropology is the analysis of human remains for the purpose of establishing identity in both living and dead individuals. In the case of the dead this often focuses on analyses of the skeleton. But any and all parts of the physical body can be analysed. The forensic anthropologist is an expert at assessing biological sex, age at death, living height and ancestral affinity from the skeleton.
Our newest research has extended forensic science’s reach from the present into prehistory. In the study, published in the Journal of Archaeological Science, we applied common forensic anthropology techniques to investigate the biological sex of artists who lived long before the invention of the written word.
We specifically focused on those who produced a type of art known as a hand stencil. We applied forensic biometrics to produce statistically robust results which, we hope, will offset some of the problems archaeological researchers have encountered in dealing with this ancient art form.
Sexing rock art
Ancient hand stencils were made by blowing, spitting or stippling pigment onto a hand while it was held against a rock surface. This left a negative impression on the rock in the shape of the hand.
These stencils are frequently found alongside pictorial cave art created during a period known as the Upper Palaeolithic, which started roughly 40 000 years ago.
Archaeologists have long been interested in such art. The presence of a human hand creates a direct, physical connection with an artist who lived millennia ago. Archaeologists have often focused on who made the art – not the individual’s identity, but whether the artist was male or female.
Until now, researchers have focused on studying hand size and finger length to address the artist’s sex. The size and shape of the hand is influenced by biological sex as sex hormones determine the relative length of fingers during development, known as 2D:4D ratios.
But many ratio-based studies applied to rock art have generally been difficult to replicate. They’ve often produced conflicting results. The problem with focusing on hand size and finger length is that two differently shaped hands can have identical linear dimensions and ratios.
To overcome this we adopted an approach based on forensic biometric principles. This promises to be both more statistically robust and more open to replication between researchers in different parts of the world.
The study used a branch of statistics called Geometric Morphometric Methods. The underpinnings of this discipline date back to the early 20th century. More recently computing and digital technology have allowed scientists to capture objects in 2D and 3D before extracting shape and size differences within a common spatial framework.
In our study we used experimentally produced stencils from 132 volunteers. The stencils were digitised and 19 anatomical landmarks were applied to each image. These correspond to features on the fingers and palms which are the same between individuals, as depicted in figure 2. This produced a matrix of x-y coordinates of each hand, which represented the shape of each hand as the equivalent of a map reference system.
We used a technique called Procrustes superimposition to move and translate each hand outline into the same spatial framework and scale them against each other. This made the difference between individuals and sexes objectively apparent.
Procrustes also allowed us to treat shape and size as discrete entities, analysing them either independently or together. Then we applied discriminant statistics to investigate which component of hand form could best be used to assess whether an outline was from a male or a female. After discrimination we were able to predict the sex of the hand in 83% of cases using a size proxy, but with over 90% accuracy when size and shape of the hand were combined.
An analysis called Partial Least Squares was used to treat the hand as discrete anatomical units; that is, palm and fingers independently. Rather surprisingly the shape of the palm was a much better indicator of the sex of the hand than the fingers. This goes counter to received wisdom.
This would allow us to predict sex in hand stencils which have missing digits – a common issue in Palaeolithic rock art – where whole or part fingers are often missing or obscured.
This study adds to the body of research that has already used forensic science to understand prehistory. Beyond rock art, forensic anthropology is helping to develop the emergent field of palaeo-forensics: the application of forensic analyses into the deep past.
For those fans of human evolutionary research news, you will be well aware of the lack of research into the role insects played in the diet of hominins over the past 6 or so million years.
This topic was addressed back in 2001 in the chapter of an academic volume by William McGrew of the department of Archaeology and Anthropology, University of Cambridge. Since then nothing has been done to address ways in which such an investigation could be conducted. What can be done to address this? Look at what we………..modern primate diets and the role insects play in their diets from the human to the Orang-utan. Let’s then look at the earliest evidence for hominin consumption of insects. South Africa has nabbed that prize, thus far. The Lower Palaeolithic sites of Swartkrans, Sterkfontein and Drimolen contained hominin fossil bone tools with wear patterns similar to those wear patterns you find on sticks used by Chimps to fish for termites. Fossil remains of Paranthropus robustus were found at these sites and the evidence suggests they were feasting on termites.
Examining the fossil evidence is one focus, but there are others including, lithics, residues, dental microwear, stable isotopes, DNA and coprolites (Fossilised shit…..basically). The dental microwear is quite problematic, because you have to take note that the tooth has been in the earth for millions of years (2.4 million years for the earliest Paranthropus specimen). Stable isotopic research is the much more promising of the topics discussed in William McGrew’s latest paper for the Journal of Human Evolution.