A new relative joins "Lucy" on the human family tree. An international team of scientists led by seven-time Leakey Foundation grantee, Dr. Yohannes Haile-Selassie of The Cleveland Museum of Natural History, has discovered a 3.3 to 3.5 million-year-old new hominin species (more closely related to humans than to chimps). Upper and lower jaw fossils recovered from the Woranso-Mille area of the Afar region of Ethiopia have been assigned to the new species Australopithecus deyiremeda. This hominin lived alongside the famous "Lucy's" species, Australopithecus afarensis. The species is described in the May 28, 2015 issue of the journal Nature.

The left edentulous half of the paratype lower jaw (BRT-VP-3/14). Photo credit: Yohannes Haile-Selassie.

The left edentulous half of the paratype lower jaw (BRT-VP-3/14). Photo credit: Yohannes Haile-Selassie.

Lucy's species lived from 2.9 million years ago to 3.8 million years ago, overlapping in time with the new species Australopithecus deyiremeda. The new species is the most conclusive evidence for the contemporaneous presence of more than one closely related early human ancestor species prior to 3 million years ago. The species name "deyiremeda" (day-ihreme-dah) means "close relative" in the language spoken by the Afar people.

Australopithecus deyiremeda differs from Lucy's species in terms of the shape and size of its thick-enameled teeth and the robust architecture of its lower jaws. The anterior teeth are also relatively small indicating that it probably had a different diet.

Casts of the jaws of Australopithecus deyiremeda, a new human ancestor species from Ethiopia, held by principal investigator and lead author Dr. Yohannes Haile-Selassie of The Cleveland Museum of Natural History. Photo credit: Laura Dempsey.

Casts of the jaws of Australopithecus deyiremeda, a new human ancestor species from Ethiopia, held by principal investigator and lead author Dr. Yohannes Haile-Selassie of The Cleveland Museum of Natural History. Photo credit: Laura Dempsey.

"The new species is yet another confirmation that Lucy's species, Australopithecus afarensis, was not the only potential human ancestor species that roamed in what is now the Afar region of Ethiopia during the middle Pliocene," said lead author and Woranso-Mille project team leader Dr. Yohannes Haile-Selassie, curator of physical anthropology at The Cleveland Museum of Natural History. "Current fossil evidence from the Woranso-Mille study area clearly shows that there were at least two, if not three, early human species living at the same time and in close geographic proximity."

"The age of the new fossils is very well constrained by the regional geology, radiometric dating, and new paleomagnetic data," said co-author Dr. Beverly Saylor of Case Western Reserve University. The combined evidence from radiometric, paleomagnetic, and depositional rate analyses yields estimated minimum and maximum ages of 3.3 and 3.5 million years.

"This new species from Ethiopia takes the ongoing debate on early hominin diversity to another level," said Haile-Selassie. "Some of our colleagues are going to be skeptical about this new species, which is not unusual. However, I think it is time that we look into the earlier phases of our evolution with an open mind and carefully examine the currently available fossil evidence rather than immediately dismissing the fossils that do not fit our long-held hypotheses," said Haile-Selassie.

Scientists have long argued that there was only one pre-human species at any given time between 3 and 4 million years ago, subsequently giving rise to another new species through time. This was what the fossil record appeared to indicate until the end of the 20th century. However, the naming of Australopithecus bahrelghazali from Chad and Kenyanthropus platyops from Kenya, both from the same time period as Lucy's species, challenged this long-held idea. Although a number of researchers were skeptical about the validity of these species, the announcement by Haile-Selassie of the 3.4 million-year-old Burtele partial foot in 2012 cleared some of the skepticism on the likelihood of multiple early hominin species in the 3 to 4 million-year range.

On March 4, 2011, Mohammed Barao, a local Afar working for the Woranso-Mille project, found the holotype upper jaw of Australopithecus deyiremeda (BRT-VP-3/1). Photo credit: Yohannes Haile-Selassie.

On March 4, 2011, Mohammed Barao, a local Afar working for the Woranso-Mille project, found the holotype upper jaw of Australopithecus deyiremeda (BRT-VP-3/1). Photo credit: Yohannes Haile-Selassie.

The Burtele partial fossil foot did not belong to a member of Lucy's species. However, despite the similarity in geological age and close geographic proximity, the researchers have not assigned the partial foot to the new species due to lack of clear association. Regardless, the new species Australopithecus deyiremeda incontrovertibly confirms that multiple species did indeed co-exist during this time period.

This discovery has important implications for our understanding of early hominin ecology. It also raises significant questions, such as how multiple early hominins living at the same time and geographic area might have used the shared landscape and available resources.

Discovery of Australopithecus deyiremeda:

The holotype (type specimen) of Australopithecus deyiremeda is an upper jaw with teeth discovered on March 4, 2011, on top of a silty clay surface at one of the Burtele localities. The paratype lower jaws were also surface discoveries found on March 4 and 5, 2011, at the same locality as the holotype and another nearby locality called Waytaleyta. The holotype upper jaw was found in one piece (except for one of the teeth which was found nearby), whereas the mandible was recovered in two halves that were found about two meters apart from each other. The other mandible was found about 2 kilometers east of where the Burtele specimens were found.

Team members crawling the area where the paratype jaw (BRT-VP-3/14) was found searching for more pieces of the specimen. Photo credit: Yohannes Haile-Selassie.

Team members crawling the area where the paratype jaw (BRT-VP-3/14) was found searching for more pieces of the specimen. Photo credit: Yohannes Haile-Selassie.


Location of the Discovery:

The fossil specimens were found in the Woranso-Mille Paleontological Project study area located in the central Afar region of Ethiopia about 325 miles (520 kilometers) northeast of the capital Addis Ababa and 22 miles (35 kilometers) north of Hadar ("Lucy's" site). Burtele and Waytaleyta are local names for the areas where the holotype and paratypes were found and they are located in the Mille district, Zone 1 of the Afar Regional State.

The Woranso-Mille Project:

Participants of the 2011 Woranso-Mille project field season. Photo credit: The Woranso-Mille project.

Participants of the 2011 Woranso-Mille project field season. Photo credit: The Woranso-Mille project.

The Woranso-Mille Paleontological project conducts field and laboratory work in Ethiopia every year. This multidisciplinary project is led by Dr. Yohannes Haile-Selassie* of The Cleveland Museum of Natural History. Additional co-authors of this research include: Dr. Luis Gibert of University of Barcelona (Spain), Dr. Stephanie Melillo* of the Max Planck Institute (Leipzig, Germany), Dr. Timothy M. Ryan* of Pennsylvania State University, Dr. Mulugeta Alene of Addis Ababa University (Ethiopia), Drs. Alan Deino and Gary Scott of the Berkeley Geochronology Center, Dr. Naomi E. Levin of Johns Hopkins University, and Dr. Beverly Z. Saylor of Case Western Reserve University. Graduate and undergraduate students from Ethiopia and the United States of America also participated in the field and laboratory activities of the project.

*Indicates a Leakey Foundation grantee.

Read More!

  1. Haile-Selassie, Y. et al. Nature 521, 483–488 (2015).
  2. Haile-Selassie, Y. et al. Nature 483, 565–569 (2012).
  3. Spoor, F. Nature 521 432–433 (2015).

This article was adapted from materials provided by the Cleveland Museum of Natural History.

 

Posted
AuthorMeredith Johnson

Franklin Mosher Baldwin Memorial Fellowships are awarded to graduate students from developing countries who would like to pursue training and/or education abroad. In providing this opportunity The Leakey Foundation hopes to equip these scholars with the knowledge and experience necessary to assume leadership positions in their home countries where there often exist extraordinary resources in the field of prehistory.

The Baldwin Fellowship was established in 1978, and its track record speaks for itself. Baldwin Fellows such as Zeresenay Alemseged, Berhane Asfew, Mzalendo Kibunjia, Jackson Njau, Agazi Negash, Emma Mbua and Fredrick Manthi (to name only a few) have gone on to productive and influential careers in the fields of paleoanthropology and primatology. 

Here are the four Baldwin Fellows from our spring 2015 cycle:

Dagmawit Abebe is a second year Baldwin Fellow from Ethiopia. She is majoring in physical anthropology at City University of New York under the sponsorship of Eric Delson. When finished with her PhD, she intends to return to her home country where she hopes to join the faculty at Addis Ababa University.

First year Baldwin Fellow Ainash Childebayeva is from Kazakhstan, and she is in the first year of her PhD studies at the University of Michigan.  Under the supervision of Abigail Bigham, Ms. Childebayeva's research focus is the analysis of human adaption genetics in high-altitude ancient Peruvian populations.

Hailay Reda is a first year Baldwin Fellow from Ethiopia. He is beginning his PhD program at the University of Oregon under the supervision of Stephen Frost.  He has extensive field experience in places such as Hadar, Wonanso-Mille and the Middle Awash Project. He is interested in studying the taxonomy and phylogeny of the Eastern African Plio-Pleistocene primates.

Abebe Taffere is a first year Baldwin Fellow who is beginning her PhD Studies at the University of Florida under the sponsorship of Steven Brandt. She intends on specializing in Late Pleistocene archaeology and lithic technology.  She would like to return to her home country of Ethiopia to work at the Authority for Research and Conservation of Cultural Heritage as the first staff member to have a PhD in archaeology.

We wish our Baldwin Fellows the very best in their studies this coming year.  We look forward to keeping you updated on their progress!

Posted
AuthorH Gregory

New research funded in part by The Leakey Foundation shows that chacma baboons within a troop spend more of their time with baboons that have similar characteristics to themselves: associating with those of a similar age, dominance rank and even personality type such as boldness. This is known as homophily, or ‘love of the same’.

Grooming. Photo courtesy of Alecia Carter.

Grooming. Photo courtesy of Alecia Carter.

This happens in humans all the time; we hang out with people who have the same income, religion, education etc. Essentially, it’s the same in baboons
— Alecia Carter

A team of researchers led by the University of Cambridge and international conservation charity the Zoological Society of London says that this may act as a barrier to the transfer of new social information to the wider troop, as previous research done by the team shows baboons of a certain age and personality type – the younger, bolder animals – are more likely to be information ‘generators’: those who solve new foraging problems.    

Given that information generators spend much of their time in the company of similar baboons, researchers say there is a risk that acquired information may end up exclusively confined to other information generators, thus decreasing the likelihood of new knowledge being disseminated to the wider troop.

Research teams tracked the same two baboon troops from dawn until dusk across Namibia’s Tsaobis Nature Park over several months each year between 2009-2014 to observe patterns of behaviour. The study is the first to monitor baboon social network structures over such a timescale and is published Wednesday in the journal Royal Society Open Science.    

“Within these big troop networks over time social preferences are generally dictated by age, rank, personality and so on,” said Dr Alecia Carter, from the University of Cambridge’s Department of Zoology, first author of the study. “This happens in humans all the time; we hang out with people who have the same income, religion, education etc. Essentially, it’s the same in baboons.”

To test for the personality traits of ‘boldness’ – essentially an assertive curiosity – the researchers planted unfamiliar foods on the edge of paths commonly used by baboon troops. These stimuli included hard-boiled eggs and small bread rolls dyed red or green. The research team then measured the time spent on investigating the new foodstuff, and whether they ate it, to determine a scale of boldness for members of the baboon troops.

“Our analysis is the first to suggest that bolder and shyer baboons are more likely to associate with others that share this personality trait,” said Dr Guy Cowlishaw from the Zoological Society of London, senior author of the study. “Previous studies in other animals – from chimps to guppies – suggests that time spent in the company of those with similar personalities could promote cooperation among individuals.

“Why baboons should demonstrate homophily for boldness is unclear, but it could be a heritable trait, and the patterns we’re seeing reflect family associations.”    

Perhaps surprisingly, says Carter, gender was not a particular obstacle to social interaction, with females preferring to groom males. This is, in part, due to the obvious sexual engagements for breeding, but also as a tactic on the part of females to curry favour with particular males for the sake of their offspring.

“Chacma baboon males will often commit infanticide, killing the babies of rivals. Female baboons try and get around this by being as promiscuous as possible to confuse the paternal identity – so males find it harder to tell if they are killing a rival’s offspring or their own,” added Dr Carter.

“They will also try and form bonds with particular males in the hope that they will protect their offspring and let the babies forage in good places with them – although males tend to be fairly lazy when it comes to this; it’s up to the babies to follow the males to good food.” 

The text in this work is licensed under a Creative Commons Attribution 4.0 International License. It was provided by the University of Cambridge.

 

Posted
AuthorMeredith Johnson
Chimpanzees are wily enough to adapt in some ways when people encroach on their turf. Kimberley Hockings, CC BY-NC-ND

Chimpanzees are wily enough to adapt in some ways when people encroach on their turf. Kimberley Hockings, CC BY-NC-ND

In the mid 20th century, when paleoanthropologist Louis Leakey sent three pioneering women to study great apes in their natural habitats, the Earth’s wilderness was still untouched in many places. Jane Goodall went to Gombe in Tanzania to study chimpanzees; at first she could only study them with binoculars from far away because the chimps would not let her approach. In those days, Gombe was not the tiny island of forest surrounded by villages and crop fields it is today. In the neighboring country of Rwanda, Dian Fossey became the first researcher to be accepted by wild mountain gorillas. In the 1960s, her “gorillas in the mist” had not yet suffered the severe impact of war and refugees. The third of Leakey’s Angels Birutė Galdikas, arrived in Borneo to study the red apes, orangutans. When she started her work in 1971, oil-palm plantations and loggers were just beginning to force orangutans into increasingly small patches of rain forest.

A baby mountain gorilla born today has never known a pristine environment free of threat from people. Bradford Duplisea CC BY-NC-ND

A baby mountain gorilla born today has never known a pristine environment free of threat from people. Bradford Duplisea CC BY-NC-ND

When these pioneering women started studying great apes in their pristine forests, the Earth had just entered a time characterized by the tremendous impact of humans on every ecosystem of our planet, what many scientists call a new epoch: the Anthropocene. Hunting, poaching and logging was taking place in the 1960s and 1970s, but the scale of the problem has dramatically increased since then.

As researchers studying great apes in the wild, we’re fully aware that there are few, if any, untouched forests left in tropical Africa and Southeast Asia. Chimpanzee sites across equatorial Africa are suffering human disturbance, but little is known about the ways in which these apes are surviving alongside their human neighbors. The unfortunate situation of declining habitat provides an interesting opportunity for science: we can study these apes in novel situations they’ve never had to deal with before and we can look for clues about our own evolutionary past.

The Bossou chimpanzees employ an old mechanism to adapt to a more recent dangerous situation.

Responding to new pressures

Is the behavior of our closest evolutionary cousins changing as human settlements and roads push into their habitats? We’ve observed that the chimpanzees of Bossou (Guinea), a field site under severe human pressure, increase their waiting time when they have to cross a large road with heavy human and vehicle traffic and wait less time before crossing a narrow, quieter road. Adult male chimpanzees are more likely to lead and bring up the rear when crossing the larger, more dangerous road with a group, in an attempt to protect vulnerable individuals in the road-crossing party, such as infants.

Apes now also need to cope with increased competition from human beings for resources such as fruits. Chimpanzees are developing new strategies to access resources that are shared with people. Adult males are more likely to take the risk to enter the village to raid human crops than females and younger individuals are; sometimes they bring these crops back to the safety of the forest to share with females. Researchers in Uganda have recorded nocturnal crop-raiding by chimpanzees. Typically, they haven’t previously been observed in activities after dark and this suggests that they are aware that the risks are lower under the cover of darkness.

Chimpanzee in Bossou demonstrates how to carry nuts and stone tools with just two feet on the ground. Jules Dore CC BY-NC-ND

Chimpanzee in Bossou demonstrates how to carry nuts and stone tools with just two feet on the ground. Jules Dore CC BY-NC-ND

Novel situations appear to trigger novel behaviors on the part of great apes. For example, we’ve recently reported how chimpanzees in Bossou exhibit bipedal behavior when they need to transport unpredictable and valuable resources, including fruits. Normally chimpanzees move around on four legs. When chimpanzees go to a village to crop-raid papayas, it’s a risky behavior since frequently the fruits grow very close to people’s houses. To minimize their exposure, chimpanzees try to carry as much as possible at once, sometimes as many as three large papayas. By running on two feet, they can carry more of a resource that might not even be available next time they return.

When apes are confronted with new human-induced challenges, we’re able to study the flexibility of ape cognition. Can they figure out how to solve problems they would never encounter if people weren’t a part of their lives? Bossou chimpanzees, for example, have been seen deactivating snares that hunters place in the forest to catch animals that will be eaten as bush meat. They’ve figured out how to free themselves from these traps, and even more amazingly it appears that they transmit the knowledge throughout their group. It’s a surprising and intelligent way of solving the problem, and something researchers haven’t observed in many other animals.<

Villagers in Bossou watch chimps carrying out a papaya raid mission.                                      Susan Carvalho CC BY-NC-ND

Villagers in Bossou watch chimps carrying out a papaya raid mission.                                      Susan Carvalho CC BY-NC-ND

Different apes living side by side

The study of how these apes face new challenges may also teach us about our own evolutionary past. Researchers René Bobe and Bernard Wood, at George Washington University’s Center for the Advanced Study of Human Paleobiology, are focused on understanding living primates and ancient human fossils to learn about our origins and evolution. They work closely with us and our colleagues studying ape responses to modern-day threats to learn about our own evolution.

For example, how do modern ape species living in the same habitats at the same time interact with one another? During the course of our evolution over many millennia, we know that human ancestors faced severe climatic and environmental changes. Some species survived and continued to evolve. Others went extinct. At various times human ancestors and close evolutionary cousins shared the same environments, much like chimpanzees and gorillas do today in parts of Africa. But we know little about how some of these ancient species competed for space and resources.

Our own species survived these challenges to become the only ape able to colonize the entire planet, and to have in its hands the survival of all other remaining apes. By looking at how great apes coexist now, we might find clues into our own evolutionary past. For instance, the chimpanzees who choose to run on two feet when rushing back to the forest with village crops hint at which pressures may have contributed to our ancestors becoming bipedal.

Human beings and chimpanzees currently share the same habitats, as do human beings and orangutans. Studies of modern sympatric apes – that is, different ape species that live in the same area and encounter one another frequently – can help us answer crucial evolutionary questions: which apes can adapt to rapid environmental change? What characteristics help them do that? How do apes avoid conflict when they must share resources with other apes?

Researchers are interested in whether a more or less specialized diet could be a barrier for adapting to a changing habitat. We also wonder about how apes avoid conflict when facing the need to share resources with other apes. One study in Congo reported interesting cases of chimpanzees and gorillas eating in the same tree at the same time. What is their way of avoiding conflict and sharing resources and space? They feed at different heights of the tree and eat different parts of the plants!

Eating and sharing papaya after crop raiding. Susana Carvalho CC BY-NC-ND

Eating and sharing papaya after crop raiding. Susana Carvalho CC BY-NC-ND

Apes' ability to adapt doesn’t mean they should have to

The problem of apes adapting to human-dominated ecosystems has to be approached carefully. We dedicate our lives to trying to save these fascinating animals, and the last thing we want is to misuse the ability of apes to survive as a justification to continue the destruction of their remaining habitats. Some might argue that if wildlife can survive in highly human-influenced areas, then why put so much effort into conservation?

However, for apes to survive this new epoch, the Anthropocene, we need to understand how apes modify their behavior under human impact. We need to understand the limits of ape adaptability. Apes cannot adapt to urban areas, unlike some monkeys such as baboons and macaques. They do not survive in cities and towns. It’s imperative to understand the limits beyond which they cannot survive.

Susana Carvalho is a Postdoctoral Scientist in Human Paleobiology at George Washington University.

This article was originally published on The Conversation.
Read the original article.

Posted
AuthorMeredith Johnson
CategoriesPrimatology

Every good story starts at the beginning. In the first episode of Origin Stories we talk with Carol Ward about one of the first things that distinguished our ancestors from the other primates, the weird way we walk around.

Carol Ward is Curator’s Professor and Director of Anatomical Sciences in the integrative anatomy program at the University of Missouri, where she directs the Ward Laboratory. Her lab is interested in the evolution of the skeleton below the neck in early African primates. Most of their work at the lab involves studying the functional morphology of modern primates and other mammals to explore what it can tell them about locomotor adaptation and evolutionary history. She’s also a paleoanthropologist who conducts field work at a site called Kanapoi in the West Turkana Basin in Kenya. Her project is called the West Turkana Paleo Project.

Professor Carol Ward overlooking Kanapoi in the West Turkana Basin in Kenya. Photo courtesy of the West Turkana Paleo Project.

Professor Carol Ward overlooking Kanapoi in the West Turkana Basin in Kenya. Photo courtesy of the West Turkana Paleo Project.

In this episode we learn about a discovery that helped answer a question about one of our most famous fossil ancestors, LucyLucy is an Australopithecus afarensis, and her skeleton was discovered in 1974 by Donald Johanson. We knew that Lucy and her species could move around on two feet by looking at things like the pelvis and femur. We also had the Laetoli footprints, which were discovered by Mary Leakey in 1978, but scientists were still missing an important piece of evidence. Lucy’s skeleton was missing something very important…the feet.

Lucy Australopithecus afarensis AL 288-1. Image via Wikimedia Commons.

Lucy Australopithecus afarensis AL 288-1. Image via Wikimedia Commons.

Donald Johanson and his colleague William Kimbel, both from the Institute of Human Origins at Arizona State University, found some new fossils at a site in Ethiopia near where Lucy was discovered. They invited Carol Ward to come to the National Museum of Ethiopia to examine them.

The new research facility at the National Museum of Ethiopia.

The new research facility at the National Museum of Ethiopia.

Photo illustration courtesy of Carol Ward.

Photo illustration courtesy of Carol Ward.

The results of Carol Ward's visit to Ethiopia and her subsequent research were published in the journal Science in 2011. You can read the abstract of the paper “Complete Fourth Metatarsal and Arches in the Foot of Australopithecus afarensis” by Carol Ward, William Kimbel and Don Johanson here. The full paper is free to read with registration on Science‘s website.

Posted
AuthorMeredith Johnson
2 CommentsPost a comment

Sarie Van Belle and howler monkeys

In December 2014, three time Leakey Foundation grantee Dr. Sarie Van Belle, of the University of Texas at Austin, was awarded a research grant for her project entitled "Paternity and kinship in socially monogamous saki and titi monkeys."

This study will examine paternity and kinship patterns in two closely related primate species (the red titi monkey, Callicebus discolor, and the equatorial saki monkey, Pithecia aequatorialis) at the Tiputini Biodiversity Station in Yasuni National Park and Biosphere Reserve, Ecuador.  Both species have been described as monogamous, a social system traditionally defined as an exclusive mating relationship between one adult female and one adult male.  However, extrapair paternity, multi-adult groups, and replacements of pairmates by intruders have become increasingly acknowledged in other purportedly monogamous primate species.  Genetic analyses that evaluate rates of extrapair paternity and the associated population genetic structure in socially monogamous species will enhance our understanding of aspects of this social system not readily documented with behavioral observations alone. 

This comparative study has the power to identify social or ecological factors crucial in the functioning and maintenance of pair-living and monogamy, particularly because saki and titi monkeys differ in the nature of male-female relationships, the level of male care provided to offspring, and the participation of each sex to territory defense.  Such analyses can contribute importantly to our understanding of the selective pressures under which monogamy evolved in primates, from which the evolution of monogamy in humans, which emerged in early hominins, can be inferred.  

Posted
AuthorH Gregory

by H. Gregory

This is the first in a series of articles written for those of you who might appreciate a little extra background information on the science behind some of the projects we share with you. Enjoy!

In this year's Spring/Summer AnthroQuest we describe how Getty Grant recipient Thure Cerling is using stable isotope analysis of tooth enamel from fossil primates in order to determine the percentages of C 3 and C 4 plants that contributed to the their diets, and in December Oliver Paine updated us on his team’s progress in analysing the mechanical and nutritional properties of C4 plants in savannah habitats . Though these projects approach the questions from somewhat different angles, they will undoubtedly help us gain a greater understanding of early hominin diets, behavior and environment. Perhaps we should take this opportunity to review some of the basic science behind the study of C 3 and C 4 plants as they relate to human evolution.

Carbon: The Building Block of Life

Yes it is! With its four valence electrons, Carbon (C) is quite suited to act as the backbone in the molecules that are the foundation of life as we know it (proteins, the nucleic acids of DNA, lipids, etc.). Carbon exists naturally in three forms (or isotopes). Remember, in non-ionized atoms the number of negatively charged electrons spinning around the nucleus is equal to the number of positively charged protons in the nucleus. Typically the number of neutral neutrons in the nucleus is equal to the number of protons. In the case of isotopes, the number of neutrons is variable.

If an isotope is stable, then unless some outside force acts upon it, this isotope will sit around and do its thing, stably, forever. Unstable isotopes (or radioisotopes) will not. They will emit energy in the form of ionizing radiation until this instability is sufficiently resolved. The end result may be a more stable isotope of the same element or even another element altogether. This is the process behind what we call radioactive decay.

Of the naturally occurring carbon isotopes, one of them is a radioisotope called 14C. (The 14 tells us that the atom contains the usual 6 electrons, 6 protons and 6 plus an additional 2 neutrons.) This radioisotope exists in trace amounts and is mainly created when carbon atoms in the upper atmosphere encounter cosmic radiation. It takes in the thousands of years for this isotope to decay into a stable nitrogen atom (14N).

It is interesting to note that the decay of 14C provides scientists with a useful tool in dating biological material, otherwise known as radiocarbon dating. By measuring the percentage of 14C remaining in non-living biological material and comparing these numbers to known values of the environment, one can estimate the age of this material. (Remember, once an animal or plant is dead, it would not be incorporating new 14C into its body.)

12C and 13C are the stable isotopes of carbon. 12C exists much more abudnantly on earth at 99%. Except for the trace amounts of 14C, 13C makes up the rest. Also, it turns out that these isotopes are utilized in different amounts by C3 and C4 plants.

Carbon Fixation

We should probably go back to our high school science classes, all the way back to the chapter on photosynthesis. This is the biochemical process by which plants use the sun’s energy, water (H2 O) and carbon dioxide (CO2) to create sugar, otherwise known to us animals as food. The process by which the inorganic CO2 is integrated into an organic sugar is called carbon fixation, and C3 and C4 plants “fix” the carbon in different manners.

C3 Pathway (or Calvin Cycle)

C3 plants are by far the most common type of plant on earth (~95%). They mostly live in environments with a moderate amount of sunlight, moderate temperatures and plenty of water, and they use the C 3 carbon fixation pathway (or Calvin cycle) to integrate the CO2 into a three carbon sugar, hence C3.

Except for humans, modern primates have a mostly C3 derived diet. They eat a range of foods (fruits, insects, leaves), all similar to those foods that would be sourced from a tropical canopy.

C4 Pathway (or Hatch-Slack Pathway)

C4 plants (tropical grasses and sedges) use the C4 carbon fixation pathway (often referred to as the Hatch-Slack pathway) to incorporate CO2 and H2O into a four carbon molecule. This process takes more energy than C3 fixation; however, C4 fixation is more efficient when it comes to its utilization of H2O and CO2. Therefore C4 plants typically live in environments with more sun (open environments), longer growing seasons and less water. The C4 pathway is a relatively recent adaptation, probably arising due to changing environment.

What do humans eat? Our diets consist of about 50% C4 derived foods. Corn, millet and rice are examples. We also eat the meat of animals that graze upon C4 plants.

So yes, it makes sense that plants have adapted to different environments. In turn, animals have adapted as well, but what about these carbon isotopes?

As I mentioned, C3 and C4 plants utilize different amounts of the 12C and 13C isotopes. This means that their bodies contain different ratios of these isotopes. For example, C3 plants have less 13C in their tissue than compared to what naturally occurs in the atmosphere. C4 also have less 13C, but this “fractionation” is less severe. This is all due to the manner in which these plants fix carbon. The biochemical pathways have differing affinities for the lighter and heavier isotopes. Without getting too deep into the chemistry, this is due to the fact that 12C can “slide” through the C3 pathway more easily than 13C can. Same is true with the C4 pathway, just not as much. The result is that the isotopic signatures of these plants are different, and the 13C/12C ratios can be measured using isotope-ratio mass spectronomy, which can measure the known behaviors of these isotopes.

Please note, I have left out CAM plants, which utilize both carbon fixation pathways. These types of plants are usually restricted to desert environments.

Cerling and Paine

Let us return to the two projects that began this conversation. Dr. Cerling is examining the 13C/12C ratios in the tooth enamel of fossil primates from Kenya. Though the ratio in tooth enamel is not exactly the same as that of the diet of the animal, this “enrichment” percentage is known, and Dr. Cerling will be able to determine the relative amounts of C3 and C4 derived food in the diet of these primates.

I keep saying derived because there are limitations to this analysis. You cannot determine whether the animal got this 13C/12C ratio from eating C3 and C4 plants or if it ate meat of an animal that ate such plants or if it was a combination of the two. However, this ratio does give us information on where these animals derived their food. As we have now learned, these C3 and C4 plants grow in dissimilar environments.

As research on early hominin diets progresses, using stable isotope analysis as well as dental microwear analysis, we are finding that perhaps our early ancestors consumed more C4 plants than earlier thought.

So, this begs the question, what exactly did they eat? If our ancestors were roaming savanna habitats through different seasons, what types of plants might they have eaten at different times? What parts of the plants might they have focused their attention, and how would they have satisfied their energetic requirements on such a diet? Oliver Paine’s project will help us begin to answer these and many more questions.

As you can see, a great amount can be learned by utilizing the properties of C3 and C4 plants as a tool to investigate the diets and environment of our early ancestors and relatives. We look forward to sharing the the results of these and other scientists in the time to come!





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AuthorH Gregory

Rob Blumenschine's Leakey Speaker Series talk, "Olduvai Gorge and the Origin of Human Ecological Dominance," is coming up on April 22, 2015 at the California Academy of Sciences. Rob will discuss how humans have become one of the most adaptable and ecologically dominant species through intelligence and technology. What makes Rob so qualified to discuss this topic?

Rob has worked with the Comprehensive Olduvai Database Initiative (CODI) to expand upon the groundbreaking work of Louis and Mary Leakey at Olduvai Gorge for over two decades. Rob and his colleague Dr. Fidelis Masao have co-directed CODI's Olduvai Landscape Paleoanthropology Project (OLAPP) since 1989, which is the longest-running of current projects at CODI. OLAPP focuses on reconstructing Olduvai's ancient landscapes and identifying signs of Homo and hominid land use, such as tool making. This project has uncovered over 20,000 stone artifacts and 25,000 vertebrate specimens. It has also uncovered nine new Homo and hominid individuals including OH 65, a Homo habilis maxilla excavated in 1995 by Rob and his team. OH 65 shed new light on variation within Homo habilis. Read further about OH 65 in the Scientific American article "Tanzanian Fossil May Trim Human Family Tree."

Rob is not only passionate about the science, but scientific outreach as well. 

“The study of our past and our origins is not just of interest to scientists and maybe to a lay public when a big fossil discovery is made; but that the field has broad relevance to each of our lives, and the society in which we live.” - Rob Blumenschine

 Rob currently is the Chief Scientific, Education, and Fundraising Strategist at the Paleontological Scientific Trust (PAST) of Johannesburg, South Africa. PAST is a non-profit dedicated to Africa’s ancient natural and cultural heritage providing public outreach, student support, technical training, youth development, research support and publication and conference support.

Join The Leakey Foundation and Rob Blumenschine on Earth Day, April 22, 2015 at 7:00 PM at the California Academy of Sciences for "Olduvai Gorge and the Origin of Human Ecological Dominance."

Tickets are available for purchase online at Calacademy.org. General Admission is $15, Leakey Foundation Members, California Academy of Sciences Members, and Seniors are $12. 

For more about Rob Blumenschine watch this interview.


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AuthorArielle Johnson
CategoriesSpeaker Series
2015originstorieslogo-e-01.jpg

Origin Stories is our new podcast about what it means to be human and the science behind what we know about ourselves. We'll have interviews and stories from scientists about their research on a vast and fascinating range of topics. We'll learn about the biology and the millions of years of evolution that shape the way we look and act today.

Our first full episode comes out in late April, and we'll have monthly episodes after that. 

When it's released, you'll be able to find it on iTunes, Soundcloud, Stitcher, or your favorite podcast app. We'll also post episodes here on our website. We hope you'll listen, subscribe, and tell your friends! 

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AuthorMeredith Johnson
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Lauren Gonzales is a PhD candidate from Duke University.  She was awarded a Leakey Foundation research grant in the fall of 2013 for her project entitled "Intraspecific variation in semicircular canal morphology in platyrrhine monkeys."

Lauren Gonzales

Understanding the functional relationship between locomotion and the morphology of the semicircular canals is an important adjunct for the reconstruction of locomotor adaptations of extinct primates. It may also be the only source of data when limb bones are unknown or fragmentary. Unfortunately, data from large populations is not available for most primate groups, and functional interpretations for extinct species may be confounded by factors such as brain-size/canal shape interactions and intraspecific variation resulting from differences in ontogenetic trajectories. The goal of my dissertation is to document intra vs interspecific variation in semicircular canal dimensions associated functionally with locomotion and to elucidate the roles of selection and constraints influencing inner ear structure.

Transparent Alouatta side view

My work concentrates on focal species matched for relatedness, body size, locomotion (defined as habitually fast or habitually slow), and components of relative brain size. To this end, I have proposed several research foci: 1. Provide data on the levels of variation found in canal radius of curvature and canal orthogonality in a large population of strepsirrhines and platyrrhines. 2. Evaluate the relative contributions of locomotor agility, brain size and body size to semicircular canal shape and size. This research will amplify and extend our knowledge of vestibular shape variation and provide the foundation from which more effective predictive models can be built and interpreted. Ultimately, a clearer understanding of intraspecific variation in canal morphology allows for a more accurate interpretation of fossil species.

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AuthorH Gregory

Alfred L. Rosenberger

In August 2009 divers of the AD Exploration Foundation discovered a well preserved skull, limb bones, ribs and vertebrae of a small extinct monkey (Antillothrix bernensis) submerged in an underwater freshwater cave in the Dominican Republic. A multi-agency team solicited the collaboration of Dr. A.L. Rosenberger of Brooklyn College to recover these remains in October 2009.

In the spring of 2010 Rosenberger and his team sought emergency funds from The Leakey Foundation to return to the cave for further fossil recovery. This was due to the fact that this cave, La Jeringa Cave, is situated near popular tourist and diving enthusiast destinations, and there presented the risk that the site would be disturbed.

In the report below, Rosenberger summarizes his team's findings and the progress they have made in demonstrating the scientific potential of flooded caves for primate paleontology.

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AuthorH Gregory
CategoriesResearch Report

In this charming animated interview from the PBS Series Blank on Blank, Jane Goodall discusses her early dreams of studying animals in the wild, and how meeting Louis Leakey in Kenya made it possible for her to start her pioneering chimpanzee research.

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AuthorMeredith Johnson

We are pleased to introduce Elizabeth Moffett, PhD candidate from University of Missouri, who was awarded a Leakey Foundation research grant in December 2014 for her project entitled "Birth and its effects on anthropoid pelvic shape and integration."

Elizabeth Moffett

Birth selection is thought to be one of the most important pressures shaping the primate pelvis. Yet, it remains unclear if and how obstetric (birth-related) selection produces consistent changes in pelvic form among primates with rigorous birth demands compared to species with relatively easy labors. Thus, there is a discrepancy between the hypothesized importance of birth in shaping the pelvis and what we actually know about the effects of obstetric demand on pelvic form. This discrepancy significantly hinders the interpretations we can make about functional pelvic morphology or how pelvic form is related to its function in extant and extinct primates, including hominins.

My research aims to explore the effects of birth-related selection on the bony pelvis using three-dimensional landmark coordinate data; this data will be collected on skeletal specimens from extant (i.e., non-extinct) primate species. Specifically, my research aims to answer the following questions: How does obstetric selection influence dimorphism, or differences between males and females within species, in the bony birth canal among primates? How do patterns of dimorphism in the birth canal correspond to patterns of dimorphism in the non-obstetric pelvis? How does obstetric demand shape integration patterns, or patterns of trait covariation, in the primate pelvis? Enhanced understanding of how obstetric demand influences pelvic form among living primates will provide insight into the form-function relationship in the primate pelvis. Moreover, this research will enable future researchers to make inferences about birth difficulty in extinct primates, including our closest fossil relatives.

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AuthorH Gregory

By Jeremy DeSilva of Boston University.

Jeremy will discuss the question "Why walk on two legs?" along with Brian Richmond during a SciCafe at the American Museum of Natural History on April 1, 2015. This article is an excellent introduction to the pros and cons of bipedalism.

Humans are weird. We are mammals, yet we have very little body hair. We are primates, yet unlike most primates, we are generally uncomfortable in the trees. Like other animals, our brain is energetically expensive to grow and maintain, yet unlike other animals, we have somehow been able to evolve a brain six times larger than expected for our size. And, perhaps oddest of all, humans navigate their world perched up on extended hindlimbs. 

Look around you today. You might see cats, dogs, squirrels, or cows. They, and most other mammals, move around on all-fours. Humans? Nope—we have released our front limbs from the duties of locomotion and left that responsibility entirely to the hindlimbs. Certainly if this behavior, and the accompanying anatomical adaptations, have evolved in the human lineage, it must have been beneficial for our ancestors. But, evolutionarily speaking, “good ideas” tend to evolve multiple times in different lineages—something called convergent evolution. For instance, the streamlined body form of sharks, marlin, ichthyosaurs and dolphins independently evolved because it is the biomechanically most efficient shape for navigating quickly through the water. The wings of bats, birds, and butterflies allow different lineages to have independently taken to the skies. 

ostrichfoot.jpg

But, what about bipedalism? While many mammals can certainly rise up on two legs and even take a few steps (think about a threatening bear, or a vigilant meerkat), there is no other mammal that habitually strides around on its back legs like humans do. Now, that is not to say we are the only animals who do this. Ostriches and other large terrestrial birds are also striding bipeds and so were their theropod dinosaur ancestors. While over 300 million years of evolution separate the ancestors of birds and mammals, the comparison between humans and terrestrial birds is not entirely useless. It allows us to see what evolution can do in a few hundred million years (the time it has taken for birds to refine bipedalism) versus a mere 5 million (the length of time our own lineage has been bipedal). And it is therefore instructive to compare the foot of an ostrich to your own. 

footanatomy.jpg

The human foot is composed of 26 bones. With your two feet, you have 52 bones in your feet—this means that roughly a quarter of all of the bones in your skeleton are in your feet. When two bones come together, they form a joint. And, motion is possible at joints—in fact, the 26 bones in your foot result in 33 joints in the foot and lots of potential for motion.  This seems a tad odd given that you need your feet to be a stable platform that converts into a rigid lever when you push-off the ground. What about ostriches? Well, all of the bones of the ankle and the sole of the foot have fused together into a single rigid structure called the tarsometatarus. The toes are reduced in number, and in total, there are only 8 bones in an ostrich foot. In fact, the foot of an ostrich looks a lot like the new design for human foot prosthetics—a single, flexible, but rigid “blade” that stores and releases elastic energy during gait and a stable, rigid base for propulsion. If ostriches and engineers have figured out this “design”, why does the human foot look the way it does? 

The answer is that evolution does not create the best “design” out of scratch. Evolution does not create perfection. It molds previous structures to produce anatomies just good enough to survive. Humans do not have feet like ostriches because our lineage has not been feathered and bipedal for 250 million years. Instead, we evolved from apes. These apes benefitted from having mobile feet, with lots of moving joints, to assist with navigation through the trees. That is the raw material from which the human foot evolved and evolution can only jerry-rig these pre-existing structures. How? Ligaments and subtle shape differences of certain foot bones have resulted in a slightly stiffer and less mobile foot in humans compared to modern apes, or our ape ancestors. This is the evolutionary equivalent of using duct-tape and paper clips to stiffen up an otherwise quite mobile structure. But, it works- kind of. 

Podiatry (foot medicine) is a billion dollar industry. Humans twist and sprain their ankles; we suffer from collapsed arches, plantar fasciitis, shin splints, bunions, and hammer-toes. Let’s face it, everyone has foot problems, and if you don’t yet, just wait. Undoubtedly, some of these ailments are a result of our wearing restrictive shoes. But, there are fossils of early human ancestors (who undoubtedly did not wear shoes) with healed ankle fractures, sprained ankles, flat feet, compression fractures, and other foot problems humans suffer from today. These afflictions have been with us from the very beginnings our unusual form of locomotion and they will continue to be with us for millennia. Why? Because we walk on modified ape feet. It is not an anatomy one would design from scratch, because we were not designed from scratch. We evolved and we retain our ape legacy all through our bodies, including in our feet. 

When your feet ache after a long day, or your shin splints flare after a short jog, you may want to curse your ancestors. But, I think you should instead thank them. Without their survival, there is no “you”, or even “us”. And, they had it much, much worse. When you break your foot, or have a severe case of plantar fasciitis, you can go to a hospital or visit your podiatrist. But, there was no such thing as a podiatrist on the predator-laden African savannah 3 million years-ago. So, how did our ancestors survive in such conditions? How did a broken ankle not guarantee death for these individuals? Certainly some of these individuals became leopard food, but we have fossil evidence that these injuries often healed. How? I propose that these fossils are evidence that as far back as 3 million years-ago, our ancestors were taking care of one another in a rather human-like way. It is just possible that the development of care and compassion in our human ancestors—qualities we hold so dear and regard as so human-like—may have developed in the context of our imperfect “design”. Bipedalism may have only worked as an evolutionary innovation in a lineage that already caring to some degree for the sick and injured. Compassion would have thus evolved as a by-product of, among other things, moving around bipedally on faulty equipment. It is a tough hypothesis to scientifically test, but worth consideration. And while you do just that, please sit—those feet could use a rest.  

Jeremy DeSilva is a functional morphologist and Professor of Anthropology at Boston University. He'll be giving a talk with Brian Richmond at the American Museum of Natural History on April 1, 2015. For more details on that see our Calendar. Admission is free.

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AuthorMeredith Johnson
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Mackenzie Bergstrom

For her PhD dissertation, Mackenzie Bergstrom of the University of Calgary studied 25 adult female capuchins living in three habituated social groups in a tropical dry forest in Sector Santa Rosa (SSR) of the Área de Conservaciόn Guanacaste (ACG) in northwest Costa Rica. To better understand how ecological and social variables affect the physical condition of these New World monkeys, the goals of this project were to document the dietary profile of these females, measure the extent of the seasonal variation in diet and nutritional intake, determine if seasonal variation in the availability of foods affects the physical condition of females and determine ecological and social correlates of energy balance and stress using urinary C-peptide and fecal cortisol.

Female white-faced capuchins (Cebus capucinus

Bergstrom conducted 12 months of behavioral observations, phenological surveys and nutritional analyses of food items consumed, radio-immunoassays of urinary c-peptide of insulin as a measure of energetic condition, and enzyme-immunoassays of fecal cortisol as a measure of stress. In the report below she describes the results of her project, providing insight into behavioral strategies employed by females at varying reproductive states and social ranks in response to proximate ecological and social pressures.  


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AuthorH Gregory

Samantha Porter in the lithics lab at the University of Minnesota

The next grantee from our Fall 2014 granting cycle is Samantha Porter. She is a PhD candidate from the University of Minnesota, Twin Cities, and her project is entitled "Investigating cultural transmission across the Middle to Upper Paleolithic transition in Western Europe."

Around 40,000 years ago, anatomically modern humans began migrating out of Africa into Western Europe.  Europe was not empty prior to this migration, but was already inhabited by our close evolutionary cousins, the Neanderthals.

Samantha Porter demonstrating how to make 3D models using photogrammetry

My research tests for evidence of cultural exchange between Neanderthals and anatomically modern humans during this tumultuous time in prehistory. It is based on the principle that social proximity between groups has an effect on the way groups apply knowledge they've learned from one another. My research hypothesizes that if groups are interacting closely, individuals will be able to learn all stages of a technological production process from start to finish. For stone tools, this encompasses both the creation of flake ‘blanks’ and the reshaping of these blanks to produce formal tools. Alternatively, if two groups are interacting with each other in a more socially distant fashion, perhaps only finding material traces of each other left behind on the pathways of the landscape, a group acquiring a new technology from another is more likely to use their own blank production methods and then attempt to replicate only the form of the final product or tool of the other group.

Samantha Porter measuring lithic artifacts in the Musée national de préhistoire in Les-Eyzies-de-Tayac, France

In short, by looking at similarities and differences between assemblages of artifacts associated with Neanderthal and anatomically modern human groups at different steps of the stone tool making process, I not only seek to find evidence of the presence or absence of cultural exchanges between modern human and Neanderthal groups but also gain a better understanding of how closely these groups may have interacted with one another.

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AuthorH Gregory
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Our understanding of human evolution has grown exponentially since Darwin's time. This week marks the 206th anniversary of the birth of Charles Darwin, so we're sharing a Darwin-related Leakey Foundation lecture from our archives. In this lecture, recorded in 2009 at the Field Museum in Chicago, Daniel Lieberman of Harvard University discusses the evolution and dysevolution of humans 150 years after On the Origin of Species.

The Leakey Foundation and the Field Museum present Dr. Dan Lieberman at The Field Museum. April 4, 2009. Full Title: Survival of the Swiftest, Smartest or Fastest: Human Evolution 150 Years After Darwin


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AuthorMeredith Johnson

The next fall 2014 grantee we would like to introduce to you is Maura Tyrrell. She is a PhD candidate from the University at Buffalo, State University of New York, and her dissertation project is entitled "Effect of competition on male coalition patterns in crested macaques."

Maura Tyrrell and a crested macaque

My dissertation focuses on the social relationships between wild adult male crested macaques (Macaca nigra) at Tangkoko Nature Reserve, Indonesia. I am specifically examining coalition behavior between males in different competitive contexts.

Competition between groups of related and unrelated males plays a large role in the political structure of early humans. However, current theoretical explanations of male coalitions in nonhuman primates focus primarily on mate competition within the group and seldom consider the influence of competition between groups. With my study I hope to create a clearer picture of social relationships in crested macaques by incorporating between-group and within-group competitive contexts into my examination of coalition and relationship qualities. I want to know if competitive context of coalitions (i.e. whether coalitions are directed towards a resident or male or an immigrating male/outside male in a neighboring group) varies with behaviors proposed to manage conflicts between individuals (i.e. "reconciling" after a fight, signaling friendly intentions, ritualized "greetings"). Additionally, does coalition partner choice in each context reflect differentiated patterns of affiliation, or is it primarily opportunistic?

The answers to these questions should help broaden our perspective of the evolution of human male coalitions by identifying components of early human alliances that may have evolved before the common ancestor of humans and chimpanzees. Findings of parallels between coalition patterns in crested macaques, chimpanzees, and humans will suggest that these parallels not only pre-date the common ancestor of humans and chimpanzees, but that they do not require male philopatry and clusters of related males. 

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AuthorH Gregory

Leakey Foundation grantees Israel Hershkovitz and Ofer Marder led an international team of archaeologists who discovered a 55,000 year old cranium in Manot Cave in Israel. Their discovery was described last week in the journal Nature

Photo courtesy of : Clara Amit, Israel Antiquities Authority

Photo courtesy of : Clara Amit, Israel Antiquities Authority

A key event in human evolution was the expansion of modern humans of African origin across Eurasia, replacing all other forms of hominin (humans and their predecessors) around 40,000-60,000 years ago. However, due to the scarcity of human fossils from this period, the path these ancestors took as they expanded out of Africa has largely remained a mystery.

Interior of Manot Cave. Photo courtesy of Amos Frumkin / Hebrew University Cave Research Center

Interior of Manot Cave. Photo courtesy of Amos Frumkin / Hebrew University Cave Research Center

The Manot Cave finding provides the first fossil evidence from the critical period when genetic and archaeological models predict that African modern humans successfully migrated out of Africa and populated Eurasia. It is also the first fossil evidence that there were populations of modern humans living near populations of Neanderthals in the Levant during the late Middle Paleolithic. This leads some to speculate that the Manot Cave people could be the population that initially bred with Neanderthals, giving all modern non-African people a little bit of Neanderthal DNA.

The Leakey Foundation recently awarded Ofer Marder of Ben-Gurion University a research grant to fund further excavation of Manot Cave. We are thrilled to be funding the exploration of this important site. We look forward to sharing news of more discoveries. 

The research appears in the journal Nature under the title "Levantine cranium from Manot Cave (Israel) foreshadows the first European modern humans" (DOI 10.1038/nature14134).

Inside the Manot Cave in Israel's Galilee, where a 55,000-year-old skull sheds new light on human migration patterns. Photo courtesy of: Amos Frumkin / Hebrew University Cave Research Center

Inside the Manot Cave in Israel's Galilee, where a 55,000-year-old skull sheds new light on human migration patterns. Photo courtesy of: Amos Frumkin / Hebrew University Cave Research Center

You can learn more about the discoveries at Manot Cave in the following articles:

"Skull Fossil Offers New Clues on Human Journey From Africa", New York Times.

"Neanderthals gain human neighbor", Nature.







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AuthorMeredith Johnson
CategoriesIn the News