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.
John Hawks discusses the latest news on the Rising Star Project:
Africa’s richest fossil hominin site has revealed more of its treasure. It’s been a year and a half since scientists announced that a new hominin species, which they called Homo naledi, had been discovered in the Rising Star Cave outside Johannesburg.
Now they say they have established and published the age of the original naledi fossils that garnered global headlines in 2015. Homo naledi lived sometime between 335 and 236 thousand years ago, making it relatively young.
They’ve also announced the discovery of a second chamber in the Rising Star cave system, which contained additional Homo naledi specimens. These include a child and the partial skeleton of an adult male with a well-preserved skull. They have named the skeleton “Neo” – a Sesotho word meaning “a gift”.
The Conversation Africa’s Science Editor Natasha Joseph asked Professor John Hawks, a member of the team, to explain the story behind these finds.
To an ordinary person, 236 000 years is a very long time ago. Why does the team suggest that in fact, Homo naledi is a “young” species?
The course of human evolution has taken the last seven million years since our ancestors diverged from those of chimpanzees and bonobos. The first two-thirds of that long history, called australopiths, were apelike creatures who developed the trick of walking upright on two legs.
Around two million years ago some varieties of hominins took the first real steps in a human direction. They’re the earliest clear members of our genus, Homo, and belong to species like Homo habilis, Homo erectus and Homo rudolfensis.
Homo naledi looks in many ways like these first members of Homo. It’s even more primitive than these species in many ways, and has a smaller brain than any of them. People outside our team who have studied the fossils mostly thought they should be around the same age. A few had the radical idea that H. naledi might have lived more recently, maybe around 900,000 years ago.
Nobody thought that these fossils could actually have come from the same recent time interval when modern humans were evolving, a mere 236 to 335 thousand years ago.
How do you figure out a fossil’s age?
We applied six different methods. The most valuable of these were electron spin resonance (ESR) dating, and uranium-thorium (U-Th) dating. ESR relies on the fact that teeth contain tiny crystals, and the electron energy in these crystals is affected by natural radiation in the ground over long periods of time after fossils are buried.
U-Th relies on the fact that water drips into caves and forms layers of calcite, which contain traces of uranium. The radioactive fraction of uranium decays into thorium slowly over time. So the proportion of thorium compared to uranium gives an estimate of the time since the calcite layers formed. One of these calcite deposits, called a flowstone, formed above the H. naledi fossils in the Dinaledi Chamber. That flowstone helps to establish the minimum age: the fossils must be older than the flowstone above them.
For these two methods, our team engaged two separate labs and asked them to process and analyse samples without talking to each other. Their processes produced the same results. This gives us great confidence that the results are reliable.
What does the discovery of Homo naledi’s age mean for our understanding of human history and evolution?
For at least the past 100 years, anthropologists have assumed that most of the evolution of Homo was a story of progress: brains got bigger over time, technology became more sophisticated and teeth got smaller as people relied more upon cleverness to get better food and prepare it by cooking.
We thought that once culture really got started, our evolution was driven by a feedback loop – better food allowed bigger brains, more clever adaptations, more sophisticated communication. That enabled better technology, which yielded more food, and so on like a snowball rolling downhill.
No other hominin species could compete with this human juggernaut. You would never see more than one form of human in a single part of the world, because the competition would be too intense. Other forms, like Neanderthals, existed within regions of the world apart from the mainstream leading to modern humans in Africa. But even they were basically human with large brains.
That thinking was wrong.
Africa south of the equator is the core of human evolutionary history. That’s where today’s human populations were most genetically diverse, and that diversity is just a small part of what once existed there. Different lineages of archaic humans once lived in this region. Anthropologists have found a few fossil remnants of these archaic populations. They’ve tried to connect those remnants in a straight line. But the genetic evidence suggests that they were much more complex, with deep divisions that occasionally intertwined.
H. naledi shows a lineage that existed for probably more than a million years, maybe two million years, from the time it branched from our family tree up to the last 300,000 years. During all this time, it lived in Africa with archaic lineages of humans, with the ancestors of modern humans, maybe with early modern humans themselves. It’s strikingly different from any of these other human forms, so primitive in many aspects. It represents a lost hominin community within which our species evolved.
I think we have to reexamine much of what we thought we knew about our shared evolutionary past in Africa. We know a lot of information from a few very tiny geographic areas. But the largest parts of the continent are unknown – they have no fossil record at all.
We’re working to change that, and as our team and others make new discoveries, I’m pretty sure we are going to find more lineages that have been hidden to us. H. naledi will not be the last.
The first Homo naledi discoveries were made in the Dinaledi Chamber. What led researchers to the second chamber? And what did you find there?
The Dinaledi Chamber is one of the most significant fossil finds in history. After excavating only a very tiny part of this chamber, the sample of hominin specimens is already larger than any other single assemblage in Africa.
The explorers who first found these bones, Rick Hunter and Steven Tucker, saw what the team was doing when they were excavating in the chamber. The pair realised that they might have seen a similar occurrence in another part of the cave system. The Rising Star system has more than two kilometres of mapped passages underground. In another deep chamber, accessed again through very tight underground squeezes, there were hominin bones exposed on the surface.
Our team first began systematic survey of this chamber, which we named the Lesedi Chamber, in 2014. For two years Marina Elliott led excavations, joined at times by most of the team’s other experienced underground excavators. They were working in a situation where bones are jammed into a tight blind tunnel. Only one excavator can fit at a time, belly-down, feet sticking out. It is an incredibly challenging excavation circumstance.
The most significant discovery is a partial skeleton of H. naledi, with parts of the arms, legs, a lot of the spine and many other pieces, as well as a beautifully complete skull and jaw. We named this skeleton “Neo”. We also recovered fragments of at least one other adult individual, and one child, although we suspect these bones may come from one or two more individuals.
Is there a way for people to view these discoveries in person?
On May 25 – Africa Day – Maropeng at the Cradle of Humankind World Heritage Site outside Johannesburg will open a new exhibit with the discoveries from the Lesedi Chamber and the Dinaledi Chamber together for the first time.
For people outside South Africa, the data from our three-dimensional scans of the new Lesedi fossils are available online.
Anyone can download the 3D models, and people with access to a 3D printer can print their own physical copies of the new fossils, as well as the fossils from the Dinaledi Chamber. It’s a great way for people to see the evidence for themselves.
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.
A team of scientists recently announced an extraordinary claim that the 130,000 Cerutti Mastodon was manipulated by hominins.
“I have read that paper and I was astonished by it,” archaeologist Donald Grayson of the University of Washington. “I was astonished not because it is so good, but because it is so bad. Cracked bones and chipped stones at a fossil site might mean anything”, said Grayson. “It is quite another thing to show that people, and people alone, could have produced those modifications. The study doesn’t take that step, he said, “making this a very easy claim to dismiss.”
Gary Haynes of the University of Nevada Reno had this to say, “The paper states that the bones were being exposed by a backhoe. These pieces of heavy equipment weigh seven to fifteen tons or more, and their weight on the sediments would have crushed bones and rocks against each other.” When asked, Holen, the study leader, said that it “was very easy to tell the difference” between fractures made by stone hammers and those seen in bones crushed by bulldozers. He did not elaborate on how the differences manifest. “He’s pretty much dead wrong — there’s no definable difference,” Haynes said. A similar fossil dispute broke out in 2015 over a 24,000 year old mammoth in Maryland, he noted, shown to be fractured by heavy equipment. Also troubling, the “hammer” and “anvil” stones described in the paper don’t unequivocally look like tools, said Michael Waters of Texas A&M’s Center for the Study of the First Americans.
Michael Waters of Texas A&M’s Center for the Study of the First Americans noted that the “hammer” and “anvil” stones described in the paper don’t unequivocally look like tools. The study also runs afoul of the mounting genetic evidence, which indicates that the first people to reach the Americas and eventually give rise to modern Native Americans arrived no earlier than 25,000 years ago.”
Date Found: March 1985
Found By: Ngrejeng Villager
Locality: Near Ngrejeng Village, Indonesia
Fossil: Partial mandible (Right side), with M1 and M2. The latter had not yet erupted at time of death.
Age: 1.02 – 1.51 million years of age
Papers to check out:
1994 – Aziz et al – Preliminary report on recent
discoveries of fossil hominids from the Sangiran area, Java.
2005 – Kaifu et al – Hominid mandibular remains from Sangiran (1952-1986) Collection
2006 – Kaifu – Advanced dental reduction in Javanese Homo erectus
Cory Marie Cuthbertson is recruiting participants for her PhD experiment running the first two weeks of April 2015, Oxford, United Kingdom. Please share, and get in touch if you would like to participate.
Everybody has heard of the Elgin Marbles and the debate surrounding the right’s of countries to those artefacts. These marbles are famous the world over but this story is repeated many more times not just in archaeology, but palaeoanthropology also. Zambia was once a colony of the British Empire and it was during that time that a certain hominin skull E 686 was uncovered. This skull is now lies in the vaults of the South Kensington Museum, London. In Zambia, Deputy Minister Susan Kawandami (pictured) recently reported before the Zambian Parliament that years of talks failed to secure the return of E 686 to Zambia with the Natural History Museum, London prepared to make copies of the skull instead. Kawandami will now establish new discussions through UNESCO, while Minister of Chiefs and Traditional Affairs, Nkandu Luo will visit London to establish a dialogue with the Trustees of the Museum.
If the Natural History Museum is ever to return the fossil, one thing is for sure, Zambia will have to convince the London Museum, that it is proactive in heritage (particularly palaeoanthropological) promotion and will ensure great care for the priceless skull. Which is currently not the case. The famed locality has no interpretative centre, no sign, no indication that two pivotal hominin bones – E 686 (Skull) and E 691 (tibia), were uncovered there. On the 17th of June 1921, A. S. Armstrong and A. W. Whittington uncovered those remains at Mutwe wa Nsofu, Mulungushi Road, Kabwe, Zambia. That same year, the fossils were given a new human species name – Homo rhodesiensis. This species has, thus far, only ever been found in Africa and it is a species that is seldom used by palaeoanthropologists. Most consider it a variation of Homo heidelbergensis. A key species that diverged into Homo sapiens (in Africa)and Homo neanderthalensis (in Europe). From about 1.5 million to 500,000 years ago, is a time that palaeoanthropologists have difficulty understanding due to the particularly patchy fossil record. So, what I have described is quite simplistic and many would argue over the exact details. The two fossils represent two adults males, that lived around 1 million years ago. Sadly, given they were found in the 1920’s, excavations in the field of human evolution were in their infancy and so, grossly inaccurate. The only way to date the site was through biostratigraphy. By looking at the animals that were found in the layers in which the fossils were found, later palaeoanthropologists compared those assemblages to strata at other sites which were radiometrically dated. The Kabwe stratigraphy was quite similar to Bed IV at the Oldupai Gorge which was dated to between 780,000 years to 1.3 million years.
Zambia’s National Heritage and Conservation Commission (NHCC) is now in the process of rehabilitating the site. Chief executive officer of the commission, Collins Chipote warned that though the site was intact, it needs to be secured and developed. A Kabwe Mining museum was commissioned by Minster Nkandu Luo (pictured), which will be run by the Lead-Zinc Mining company Enviro-Processing Ltd. a subsidary of the giant Berkeley Mineral Resources PLC. More effort is required on the part of Zambia to show that they have the determination to celebrate their priceless heritage and right now, there seems to be no action, but plenty of talking.
The ‘Black Hole’ of Palaeoanthropology is not a term you hear very often, but then again what is there to say about the biogeographic history of a 1.77 million square kilometer region (Turkey, Saudi Arabia, and Iran) with virtually no faunal, human or archaeological sites. At this point it would seem easy to resign yourself to the words of Timothy D. White at the dawn of the 21st century, that we are not going to find many more fossil hominins. The mark of a great palaeoanthropologist is to never give up that curiosity for the unknown. Since White’s depressing prediction, he has been roundhouse kicked to Wrongville, with the spectacular finds of Ethiopia, South Africa, Myanmar, China, Flores and much much more. We have learned so much thus far, don’t lets forget this. Sounds great but these inevitably throw up more questions than answers. And the ‘Black hole’ is a particularly hard nut to crack.
What does archaeology have to offer? Ethiopia features the earliest concrete evidence for hominin stone tool manufacture. At 2.6 million years of age it predates the earliest known human – Homo habilis – by less than 300,000 years years (Fossil Code: A.L. 666). Saudi Arabia has a rather rich representation of Mode 1 (Oldowan) stone tool clusters. If you don’t know to millimeter accuracy where the stone tool was found, or if it is a surface find then it is worthless to science. The Saudi sites were also used during the Holocene (11,700 years ago to present), begging the question how can you separate Early Pleistocene (2.5 million years ago to 700,000 years ago) from Holocene activity? At least we can tell that hominins took one route out of Africa. Stone tools similar to the Oldowan found at Perim Island supports the hypothesis that early hominins crossed the Bab al Mandab Strait (20 miles wide). Iran has probably the most depressing lack of archaeological evidence of the region. Isolated finds dominate, both the Oldowan and Acheulean records of Iran and few excavations have taken place. South of the Caspian Sea is the site of Ganj Par, which yielded 100 limestone tools within half a hectare. This assemblage shares similarities with those of Ubediya, Israel and the Oldupai Gorge (also known as the Olduvai Gorge), Tanzania. Turkey repeats much the same story. Of the 200 Palaeolithic sites, less than 25 have been even partially excavated. The majority are restricted to the fringes of the Anatolian plateau. None are any older than 1.3 million years of age, further supported by Argon-Argon dating of Kula, western Turkey to 1.24 million years of age. The site was the location of a palaeomeander which contained a solitary Quartz flake, 5 x 4 cm. Volcanic activity interfered with the palaeomeander and it was that lava flow that allowed the date to be so accurate. The take-home-message from Turkey is the earliest securely dated archaeological remains support the 1.1 million years calculated for the Kocabas skullcap, which shares affinities with OH 9 and KNM ER 3733, attributed to H. erectus. Debate continues as to its taxonomic status, but it does reflect a great deal of H. erectus characteristics. The Archaeology tells us that hominins with the ability to make stone tools were already out of Africa 1.8 million years ago, at the site of Dmanisi, Georgia.
It is the richest fossil hominin location at the ‘black hole’ fringe. The Fall of 2013 was just another milestone in sites long history of archaeological investigation. The discovered cranium (D4500) was reunited with its jaw (D2600) and the team of palaeoanthropologists led by David Lordkipandize concluded that the five individuals represented members of the same species, but retracted the classification of D2600 (Homo georgicus) for Homo erectus ergaster georgicus. This raised some eyebrows in the palaeoanthropological community, particularly Fred Spoor, palaeoanthropologist and lecturer at the UCL Department of Anthropology, who pointed out that such an action is not outlined in the code of zoological nomenclature. This is a minor debate in the palaeoanthropology, but most agree that Homo erectus exhibited a variation comparable to that seen in modern Homo sapiens today. Dmanisi is proof that hominins were already out of the African continent by 1.8 million years. Additionally, although the dating of the hominins of Java are in the doldrums, these specimens could be as much as 1.8 million years of age. Prior to that time some hominin species made it’s way north, but which one?
On the 23rd of January 1995, a French-Chadian team of palaeontologists discovered a fragment of fossil jaw (Fossil Code: KT 12/H1) lying on the gravel desert of northern Chad. The fossil (nicknamed “Abel”) could not be accurately dated, nevertheless stratigraphic layers nearby suggested it could as much as 3.5 million years of age. Back then, the river Bahr El Ghazal flowed into a 3 million square kilometer lake called Megachad. This hominin foraged on grasses that dominated the Koro Toro region. The palaeontologists gave “Abel” a new species name – Australopithecus bahrelghazali distinguishing it from another australopithecean – Australopithecus afarensis. That species lived in the eastern region of the continent, over 2,500 km from the Bahr El Ghazal site. The animal remains found in the stratigraphic layers of both regions were pretty much identical, which means the ecosystems were the same. Therefore, you can see why some palaeoanthropologists consider it plausible that “Abel” is just another Au. afarensis. This goes back to the argument that, what we are looking at here is just another variation of the same species. Either way, here we have australopitheceans in eastern and north central Africa. Theoretically, it is plausible for australopitheceans to have made their way into Arabia.
Every organism has a landscape format that they thrive within. Lions are quite at home in the savannah, Tigers frolick in the dense jungles of the Indian subcontinent and hominins, particularly australopitheceans, were quite at home in savannahs. If we are to prove that they made their way into Arabia, there should be an extension of savannah into the Eurasia 3-4 million years ago. Sadly we are not seeing this, but what do we see. The faunal record of Saudi Arabia is particularly fragmented and sparse. Western Turkey (Calta) 2.3 million years ago, saw Raccoons, Giraffes, Hippos and the extinct “Running” Hyena. Many associate Bethlehem with the Christian story, but few know that at about the same time, this region featured Raccoons, Sabre-Toothed Cats, Rhino, an ancestor to the Mammoth and ancestor to the modern boar. While 110 kilometers north of Bethlehem and 700,000 years later, Baboons lived south of the Lake of Tiberias, around Ubeidiya. Lakes were magnets for faunal activity and therefore hominin activity.
The An Nedfud desert of northern Saudi Arabia is classic wilderness today, 2 million years ago it was the hub of a diverse ecosystem with a lake as the centrepiece. The faunal remains were recovered from three localities and share similarities with the kind of fauna you would expect at Ubeidiya and the Oldupai Gorge. Hippos were found at these sites and since modern day counterparts prefer standing water to a depth of 5 meters, it gives an initial sense of the size of ‘Lake An Nedfud’. A lake capable of supporting fish life, but this is not the only lake to have supported faunal biodiversity in the ‘Black Hole’. ‘Lake Negev’ developed around 1.8 and disappeared around 1.5 million years ago under ever increasingly arid conditions. It supported fish populations and laid down 15 m thick sediments over 18 sq km². Besides these lakes, there were smaller lakes, Oases and springs that would have allowed hominins to hop, skip and jump out of Isis territory and into the more accommodating environments of Europe and eastern Asia. Looking at the faunal remains you can get a sense of the climate that prevailed at whatever time period you are interested in. The climatic mapping of the Pliocene and Early Pleistocene of the ‘Black Hole’ are, you’ve guessed it understudied. We do know that two and a half million years ago, the forests of Azerbaijan gave way to Savannah and the Arabian peninsula experienced 2 million years of humid conditions, capable of keeping many large (now extinct) rivers topped up.
There you have it. We know alot, but we know so very little about this massive region of the world. We lack fossil hominins in this region and I don’t think Isis would be willing in finding their early ape ancestry any time soon. It would definitely be a useful distraction from Wahhabism. Do something useful for a change, Isis! Get out there and find us those damn fossils! You ignorant misogynistic apes!
I recently came across this scientific article in the Journal of Human Evolution entitled, Ancient DNA Analysis of Dental Calculus by Weyrich et al. It reminded me of the research conducted on the Indonesian hominin, Homo floresiensis. So, here I summarise what we know thus far. Dating to between 95,000 and 17,000 years ago, the hominin was found in the cave of Liang Bua, overlooking the Wae Racang river valley, on the island of Flores. It’s most remarkable feature was the 1.06 m stature of the individual found. Begging the question, how is this hominin related to us and what led to its diminutive stature. Much of the debate was thoroughly summarised in Leslie Aiello’s paper entitled, Five Years of Homo floresiensis, back in 2010. In short, some questioned the validity of naming these individuals a new species of human. Evidence was brought forward to support the hypothesis that these people were suffering from the neurodevelopmental disorder, Microcephaly and other diseases that induce a reduced stature. As time has passed, media sensation abated and researchers had a chance to step back, the majority are now more accepting of the Australian-Indonesian team’s decision to apply the new hominin nomenclature. Much of the debate hinges on skeletal comparisons between Homo floresiensis and other hominins, like us. There is one piece of information that the individuals of Liang Bua have yet to reveal – Deoxyribonucleic Acid.
Two teams of scientists, the Australian Centre for Ancient DNA (ACAD) and the Department of Evolutionary Anthropology at the Max Planck Institute (MPI) attempted and failed to extract DNA from the individual’s teeth in 2006. This was due to the environment in which the hominins were found, which was not conducive to DNA preservation. Christina Adler of ACAD hypothesised that the reason for extraction failure could be due to extraction procedure. In 2007 the ACAD team sucessfully extracted DNA from a pig tooth unearthed at the Liang Bua Cave, which was about 6,000 years old. The team suggested that first, Cementum (calcified root covering) is the richest source of DNA and second, drilling the specimen destroys the very molecule they are after. Armed with this knowledge another attempt to extract DNA from the hominins of Liang Bua is still yet to be carried out. The year 2013, saw the successful extraction of 400,000 year old DNA in Spain, so Floresiensian DNA may still lie within the teeth. I’m hoping, despite the less than ideal high temperatures of the cave sediments, there lies within those hominin individuals such strands of the good stuff.
Returning to the paper I mentioned at the beginning, it is a summary of all we know regarding the extraction of aDNA and steps to take when extracting it from calculus on teeth. Calculus is a hardened group of micro-organisms that appear as a yellow build-up usually around the gum-tooth boundary. The first demonstration of aDNA in Calculus was documented in a paper entitled Ancient Bacterial DNA (aDNA) in dental calculus from archaeological human remains by Preus et al., in 2011. A year later, aDNA was extracted from Neolithic Argentinian and Chilean humans. In that study, five bacterial species gene sequences were amplified by targeted polymerase chain reactions (PCR). By 2014, Warinner et al., used the power of the metagenomic sequencing strategy demonstrated increased resolution, the identification of antibiotic resistence genes and though the specimens were put through an Ethylenediaminetetraacetic acid (EDTA) and bleach treatments, DNA was recoverable.
When analysing hominin diets, microfossils are a large component, but the strides being made in aDNA extraction will mean that the species of plant or animal will be identified or as it usually does, throws up more questions than answers.