A complete 1.8 million year old skull found from Dmanisi, Georgia could be evidence that early hominids are actually all members of a single species. Researchers published their analysis in Science today and argue that the skull’s combination of primitive and more evolved features, such as a small braincase (546 cubic cm) with a large prognathic face.., Similar morphological affinities with the earliest known Homo fossils from Africa, which make it difficult to classify by now accepted definitions of early hominid species.
This month in the Journal of Human Evolution, a new study on the teeth of the Dmanisi Homo erectus has been published. A site in the Republic of Georgia, Dmanisi has yielded a vast quantity of hominin fossils dating to approximately 1.8 million years ago—even an elderly individual without teeth. The discovered crania are remarkably well-preserved, and have given scientists the ability to look at our evolutionary history with higher resolution.
Based on the skeletal remains, how can we ascertain specifics about hominin diet? For this particular study, researchers used microwear analysis on two molars from Dmanisi. Microwear analysis observes the patterning left on teeth by components of specific diets. As one example, tough silicates in plants leave identifiable traces, as do other silica-based sands that end up being chewed.
Comparisons in wear patterns were made with Dmanisi H. erectus and African H. erectus as well as the genus Australopithecus and earlier Homo, to get an idea of where the Dmanisi hominins fit in on the spectrum of microwear diagnostic traits. These diagnostic traits include heterogeneity of the tooth surface, as well as complexity in the roughness of the tooth surface. To give you an idea of general evolutionary trends, Australopithecines typically had larger teeth and thicker enamel to break down tougher, lower quality foods. As later Homo emerged, teeth tended to get smaller and enamel thinner.
The results indicated that the molars of Dmanisi Homo erectus were very similar to African Homo erectus in general. However, there were also characteristics found to be consistent with other earlier hominin species. Overall the authors cautioned against drawing conclusions with such a small number of teeth, saying that meaningful statistical results are unattainable based on the sample size.
According to authors, the wear patterns on the Dmanisi teeth are indicative of hominins that exploited a range of foods. It seems then that versatility and not specialization is what defines H. erectus in both Africa and Europe. The ability to take advantage of a larger resource base is no doubt one of the factors that allowed the first hominins to spread out across such an expansive area.
By Matthew Magnani
Pontzer, H., Scott, J.R., Lordkipanidze, D., Ungar, P.S. 2011.“Dental microwear texture analysis and diet in the Dmanisi hominins.” Journal of Human Evolution 61:683-687.
A new paper published in Anthropological Science claims that comparative skull analyses between the hobbit skull and various others from H. sapiens and a plethora of archaic others, indicates to the authors of this study that the diminutive humans, whose remains were discovered on the island of Flores descended from Asian Homo erectus.
The paper is free to access, and although I haven’t had time to read it through, looks set to cause yet more rumblings in the ongoing debate between those who contend H. floresiensis was a microcephalic H. sapiens, and those who believe that an entirely new species of human has been discovered. Here’s the abstract…
Since its first description in 2004, Homo floresiensis has been attributed to a species of its own, a descendant of H. erectus or another early hominid, a pathological form of H. sapiens, or a dwarfed H. sapiens related to the Neolithic inhabitants of Flores. In this contribution, we apply a geometric morphometric analysis to the skull of H. floresiensis (LB1) and compare it with skulls of normal H. sapiens, insular H. sapiens (Minatogawa Man and Neolithic skulls from Flores), pathological H. sapiens (microcephalics), Asian H. erectus (Sangiran 17), H. habilis (KNM ER 1813), and Australopithecus africanus (Sts 5).
Our analysis includes specimens that were highlighted by other authors to prove their conclusions. The geometric morphometric analysis separates H. floresiensis from all H. sapiens, including the pathological and insular forms. It is not possible to separate H. floresiensis from H. erectus. Australopithecus falls separately from all other skulls. The Neolithic skulls from Flores fall within the range of modern humans and are not related to LB1.
The microcephalic skulls fall within the range of modern humans, as well as the skulls of the Neolithic small people of Flores. The cranial shape of H. floresiensis is close to that of H. erectus and not to that of any H. sapiens. Apart from cranial shape, some features of H. floresiensis are not unique but are shared with other insular taxa, such as the relatively large teeth (shared with Early Neolithic humans of Sardinia), and changed limb proportions (shared with Minatogawa Man).
The putative link to H.erectus isn’t entirely unexpected, if only from a geographical perspective, because the island of Flores was also home to these archaic humans some 840,000 years ago – as with the so-called hobbits, nobody is quite sure how they managed to arrive on an island so long ago, when a sea crossing was the only available means of access.
(via Mundo Neandertal)
image via online paper
The Origin of Homo floresiensis and its Relation to Evolutionary Processes Under Isolation. (PDF) (HTML) G.A. Lyras, M.D. Dermitzakis, A.A.E. Van der Geer, S.B. Van der Geer, J. De Vos. Anthropological Science 117(1), 33–43, April 2009.
The 7th Human Evolution Symposium, Hobbits in the Haystack: Homo floresiensis and Human Evolution was held yesterday at Stony Brook. Turnouts were great despite damp and rainy weather. Convened by Richard Leakey, the symposium was an all day event where researchers share their findings on Homo floresiensis. The highlight of the symposium is the first ever complete cast of LB1, or Flo and a host of Homo floresiensis researchers.
The symposium ended with questions and issues for discussion by Richard Leakey. Then, the floor was opened for general Q&A session with the panel.
“Accepting it (Homo floresiensis) will require us to rewrite the textbooks.” – William Jungers, Stony Brook University.
Here is a list of topic presented by speakers during the symposium:
- “Hobbits in context: life, times and death of Homo floresiensis” by Michael J. Morwood, University of Wollongong, Australia.
- “Digging up Hobbits: The Excavations at Liang Bua” by Thomas Sutikna, National Research and Development Centre for Archaeology, Indonesia.
- “Stone Tools and Hominins on Flores” by Mark Moore, University of New England, Australia.
- “Whence Homo floresiensis? Clues from the brain.” by Dean Falk, Florida State University.
- “Her Teeth Were Sharp, Her Gums Were Raw, and Spit Was Dripping From Her Jaw: The Little Things That Make Us Human” by Peter Brown, University of New England, Australia.
- “Why the Tiny Wrist Bones of a Hobbit Tell Us So Much About a Big Chapter in Human Evolutionary Theory” by Matthew Tocheri, Smithsonian Institution.
- “The Hobbit Shrugged: The Shoulder of Homo floresiensis and its Implications For Human Evolution.” by Susan Larson, Stony Brook University.
- “Can Island Dwarfing Explain Hobbit Body Size and Shape?” by William Jungers, Stony Brook University.
- “Virtual Hobbits and Health in Homo floresiensis” by Charles Hildebolt, Washington University in St. Louis.
A list of what Richard Leakey commented and asked during the symposium:
- We should be careful when using Lucy as model for comparison because Lucy is not representative of the genus Australopithecine in general.
- We don’t have Homo erectus feet in our fossil record. The fossilized foot prints that were found in Ileret, Kenya has been suggested that it was left behind by Homo ergaster, an earlier version of Homo erectus.
- There should be more discussion on the types of dating methods used on Homo floresiensis and the artifacts found in association with it.
- There should be more discussion and research to link lithic materials to the Hobbits, or Homo floresiensis.
- What were the geographic isolation of Flore? How did the Hobbits ended up in Flores?
- Were there large carnivores in Flores or lack thereof? Hobbits have ape-like feet that were built for walking but not for running. Did they survive despite that because they have no need for speed to get away from predators?
Originally posted on The Prancing Papio.
The upcoming issue of Science will be publishing the announcement of a newly discovered 1.2 million-year-old female Homo erectus pelvis. The fossil was found in 2001 at the Gona Study Area in the Afar region Ethiopia. Excavations were completed in 2003.
Sileshi Semaw, the leader of the Gona Project, said that the birth canal of this pelvis is 30% larger than earlier estimates based on the 1.5-million-year-old juvenile male pelvis of KNM-WT 15000 (Turkana Boy) found in Kenya. I don’t have an early copy of the paper, but if this is true, this find will make us reevaluate our estimations of Homo erectus growth and development. Current theories, based upon estimations of the existing male skeleton from Kenya, suggested Homo erectus produced babies with only a limited neonatal brain size, and experienced rapid brain growth while still developmentally immature. But as you may know, male and female primate pelvic girdles are extremely different. This new pelvis also tells us of some interesting differences in stature and gait.
Early hominid female pelvic anatomy is basically unknown, in fact we don’t really have much data, really only Lucy’s fragmented pelvis, the 3.2 million year old Australopithecus afarensis. So I’m interested in reading more about this fossil and what it has to tell us of Homo erectus anatomy and early human evolution. I guess I gotta wait until the paper appears in Science. Expect a post about it as soon as I get my hands on the paper.
John Hawks shares with us news of a new hominid discovery. Similar to the post from a couple days ago, this is news of mandible of Homo erectus. Unlike the Serbian mandibular fragment, this is a complete jaw and was discovered at the Thomas I quarry near Casablanca by a French-Moroccan team co-led by CRNS research Jean-Paul Raynal.
The Thomas quarries are part of a series of quarries in a suburb of Casablanca called Hay Hassani. Thomas I has already yielded hominid remains. In 1969 another jaw was discovered, but it was only the left mandible and since then four human teeth were excavated. Other quarries nearby, such as Oulad J’mel and Sidi Abderhamane have also yielded interesting Acheulian archaeological finds in the past.
If you want more information about the Thomas, Oulad J’mel, and Sidi Abderhamane localities, I found this link pariticularly useful. The importance of Thomas 1 is also mentioned several times in Desmond Clark’s ‘History of Africa‘ text, which is offered by Google Books — so check it out. In the meantime, we’ll have to wait until a full analysis is done and submitted to a journal to know more about the the specimen and the geological context it came from.
Update July 2nd, 2008: Bram shared a link with a photo of the forementioned fossil. Here it is, click to see the original news (in French).
John Hawks just pointed out a press release announcing a new hominid from Serbia. The site is a cave in the Sicevo Gorge. The site is dated to the Middle Pleistocene, or around 130,000 to 250,000 years old. The press release doesn’t provide a definitive dating technique, just saying that the,
“The [remains were] found at a depth of four meters, below a Neanderthal village.”
The specimen is a mandibular fragment with three complete teeth. Dusan Mihailovic, the leader of the excavations at Sicevo Gorge thinks the jaw is of a Homo erectus, but again the press release doesn’t provide any information of a thorough comparative analysis…
Here’s a photo of Dusan Mihailovic holding the mandible:
Another PNAS study to share with y’all, this time I caught the announcement via ScienceNOW. ScienceNOW says the paper is out today, but I can’t find it. Go figure. So all I got to run with is this news report.
“from the island of Flores is unlikely to be a shrunken or diseased Homo sapiens, as some have argued, and that its ancestry may instead trace back to ancient Homo species in Africa.”
Two weeks ago we read a very flawed article that concluded Homo floresiensis was nothing more than a bunch of endocrine-ly challenged modern humans. There’s been a so much back and forthing on whether or not Homo floresiensis is a unique species that is has become tiresome to even keep up with the arguments. Sometimes it feels like ego is at more at stake here than really figuring out human evolution.
This new study seems to want to simplify things. From the news article,
“The researchers gathered published data on six measurements of skull shape, such as the height of the cranium and the forward jut of the jaw, on 2524 modern humans, 30 ancient hominids of various species, and the hobbit. Statistical analysis showed that the hobbit skull most resembled H. erectus skulls from Africa and Dmanisi, Georgia, dating as far back as 1.7 million years ago. Then, because the skull’s tiny size presumably influences its shape in certain ways, the researchers did a second analysis considering the effects of scale–in effect asking what type of hominid, if shrunk to hobbit size, would best match LB1. In this part of the study, LB1 most resembled African H. habilis, the most primitive and small-brained species of our genus, also dated to about 1.7 million years ago.
“This is particularly exciting because … it suggests that we really do have a hominin lineage that split off from our own as much as 1.7 million years ago, yet persisted up until the time when modern humans started peopling the Americas,” says Gordon.”
To recap on some osteological goodness, the six measurements are as follows:
- Glabella to Opisthocranion, a measurement of the maximum length of the skull. That’s from the front to the back of the skull.
- Basion to Bregma, a measurement of the of the maximum height of the skull. That’s from the base to the very tip top point of the skull.
- Euryon to Euryon, a measurement of the maximum breadth of the skull. That’s from one side to the other side.
- Nasion to Basion, a measurement of the length of the base of the skull.
- Basion to Prosthion, a measurement of the distance between the base of the skull to the tip of the maxilla (upper jaw).
- Biasterionic breadth, a measurement I haven’t heard of but looks like it is the width of the base of the skull.
I’m gathering that the authors took these multiple measurements and did a phylogenetic analysis. I am getting this from what was indicated in the above excerpt, they compared a lot of modern humans, fewer hominids of various species, and the hobbit. I don’t have the article to confirm this methodology, but I can only assume that is what they did to figure out LB1 is similar to Africa and Dmanisi Homo erectus, even H. habilis in some regards, based off of the measurements.
But, if you have read this paper, “Remains of Homo erectus from Bouri, Middle Awash, Ethiopia,” you should know how reconstructing phylogeny with cladistic analysis between early Homo species is hard and rather inconclusive. We know general trends and large scale similarities and differences, but when it gets to nitty gritty things, the paltry calvarial evidence for big differences between the African and Asian fossils make it really difficult to say Asian Homo erectus was that much different from African Homo erectus. Instead, it is much safer to say that Homo erectus existence spanned large time frames. And that even with a 1.2 million year old difference in time, Homo erectus from Africa to Asia was pretty much the same thing.
For that reason, I wonder how LB1 can be like Homo erectus… especially a really old African erectus as indicated in the report? Above, I put a lateral view of LB1 as well as a lateral view of a Dmanisi Homo erectus (D2700), one that the authors say LB1 resembles. Just by eyeballing the differences between the two skulls we can see that D2700 is much longer, and has a big difference in the basion to prosthion length.
If we take into consideration the works of Asfaw et al., there aren’t many differences between African and Asian Homo erectus that can be figured out thru cladistics. And Asian Homo erectus persists in the record into much more recent times. So, why isn’t LB1 related to an Asian Homo erectus? They should be synonymous, no? What is particularly African erectus about LB1?
Furthermore, how can a tiny hominid like LB1, with a brain half the size of Homo erectus and an antiquity of only 18,000 years old, be compared to one of the root species of Homo? Some of the earliest Homo had brain sizes of 900 or so cc. LB1 had a brain size of 440 cc. Big difference here folk. The news article reports that they ‘shrunk’ the proportions of other early Homo skulls down to LB1’s size to compare. Is that even a valid way to compare? The very fact that LB1 is distinct is its size, so scaling down comparative measurements seems flawed because we’re comparing apples to
oranges watermelons here. You can’t just scale down a watermelon down to the size of an apple and begin to start concluding their similar.
I’m not alone scratching my head over this. Christoph Zollikofer, also has some problems with this cladistic approach. He says the six measurements aren’t enough to
“capture the complexities of skull shape, a concern shared by others. In his view, this kind of analysis might cluster together skulls that are actually distinct. Depending on the species included, says Zollikofer, the approach could end up finding similarities between LB1 and chimpanzees.”
I guess we all gotta wait until PNAS puts out this paper.
- Asfaw, B., Gilbert, W.H., Beyene, Y., Hart, W.K., Renne, P.R., WoldeGabriel, G., Vrba, E.S., White, T.D. (2002). Remains of Homo erectus from Bouri, Middle Awash, Ethiopia. Nature, 416(6878), 317-320. DOI: 10.1038/416317a
EurekAlert is running a very interesting press release on the discovery of a 500,000 year old Homo erectus fossil recovered from Turkey. Apparently the fossil, a fragment of skull bone, shows lesions that the individual had tuberculosis.
Tuberculosis is a deadly infectious disease caused by multiple strains of mycobacteria. Because the mycobacteria have lost numerous coding and non-coding regions in its genome, it is hard to retrace the genetic differences that would tell us of the origins, relationships, and movement of the disease causing pathogen. But through analyzing relatively modern human skeletal remains (I’m talking thousands of years modern) from Egypt and Peru, we know that tuberculosis was taking a big toll on humans relatively recently in our evolutionary history.
If this Homo erectus really did have tuberculosis, then that means he probably, and other hominids, got sick because his body produced less vitamin D due to darker skin and had a less vigilant immune system, hundreds of thousands of years ago. From what’s reported in the press release, I don’t buy it. And neither does John Hawks. I think it is over analyzed and sensationalized science to make big headlines.
I really don’t understand why a Homo erectus from Turkey isn’t enough of a killer headline. To my knowledge this is the first hominid found in Turkey and it fills a big spatial gap in understanding human evolution. Of course, I really don’t know enough about the tuberculosis evidence in this individual to make a solid judgment… we’ll have to wait until we get the paper…
Speaking of which, paper should be out anytime soon in the American Journal of Physical Anthropology, so the entire details of the fossil aren’t known to us until the AJPA decides to give the green light and publish the paper. I have, however, discussed this press release with several colleagues and they are all skeptical.
The first thing they are curious about is the date. We speculate that dating was established using faunal evidence. The problem with that is the faunal composition of Turkey during the Pleistocene isn’t well known. Sure, the late Miocene is, and that’s cause there are a lot of Miocene sites… but at 500,000 years ago it is hard to correlate a date to what organisms were around at the time.
I also got word that John Kappelman, and his team damaged the fossil. I don’t know if it was during excavation, transportation, or curation/research, but having rumors run around that your team damaged the first ever Turkish hominid isn’t something the bolsters ones reputation in the field. But again, take this with a grain of salt… it is a rumor. There aren’t any official reports that his team actually broke the fossil, and if Kappelman’s not really liked, I can see how people will start up these things. Physical anthropologists are a catty bunch. But to be really honest, I can’t help but think the tuberculosis is a smokescreen to distract attention from this broken specimen.
KNM-WT 15000 was found by Kamoya Kimeu in 1984 at the Nariokotome site near Lake Turkana in Kenya. It the most complete specimen of Homo erectus to date. All that’s missing from this 12 year old boy are the hands, feet, and left humerus. Its completeness and its 1.6 million years old age undoubtedly makes it an important specimen to anthropology and the study of human evolution
So to read from Ann Gibbons of Science that Turkana boy has been shipped to The Field Museum in Chicago, Illinois to be exhibited rings all sorts of alarm bells that rang when I read about Lucy’s trip to the west.
What if he gets damaged? Why doesn’t a really well done cast suffice?
I doubt that he will get damaged, it is a possibility, but people are really careful when packaging and handling priceless fossils like this. And about the cast, I must confess that I would personally be awestruck to see one of the most complete specimens of early Homo in person… especially because Turkana boy packs a lot of human like traits at 5′ 3″ tall. But what’s going on here? Why all of a sudden have two important hominid fossils been sent off to the US?