We are pleased to introduce you to another one of our newest grantees, Amanda Lea, PhD candidate from Duke University.  She was awarded a Leakey Foundation research grant in the Fall of 2014 for her project entitled "Effects of social conditions on DNA methylation and immune function."

Amanda Lea

Many primates, including humans, live in complex social environments in which both competitive and affiliative interactions are common. The capacity to deal with this environment can vary substantially across individuals. While some individuals form stable, positive social bonds, others do not; similarly, only some individuals are able to achieve high social status. Research in both humans and nonhuman primates suggests that variation in these social experiences can have profound effects on physiology, health, and survival. However, we do not understand the molecular mechanisms that mediate these effects.

Baboon (Papio cynocephalus) in Amboseli, Kenya

To address this gap, my project tests the hypothesis that social adversity influences health-related traits by altering the way genes are expressed. Specifically, it asks whether low social status and/or social isolation lead to changes in DNA methylation (an environmentally sensitive modifier of gene expression) and whether these changes predict how individuals respond to an immune challenge. To do so, my project combines behavioral data from wild baboons in Amboseli, Kenya, with measurements of genome-wide DNA methylation levels and immune-related gene expression patterns.

Together, the resulting data will shed new light on whether, and to what degree, social experiences influence immunological traits that likely contribute to health and survival in wild primates. Identifying these connections is crucial for understanding the evolution of primate sociality, and for addressing the well-documented health consequences of social adversity in human populations. Finally, by using a genomic approach, I will be able to identify specific genes involved in the response to the social environment, which are likely to have been important in the evolution of group living in primates. 

More information:

Amboseli Baboon Research Project
The Alberts Lab - Duke University
The Tung Lab - Duke University
"The Role of Methylation in Gene Expression" - Nature Education
"Baboon Watch" - Science Magazine

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AuthorH Gregory

Michael Granatosky, PhD candidate from Duke University, was awarded a Leakey Foundation research grant in our most recent granting cycle for his project entitled "Gait mechanics of inverted walking: Implications for evolution of suspensory behavior."

Michael Granatosky at the Duke Lemur Center

Specialized arm-swinging locomotion has arisen independently numerous times during the evolution of primates and yet has never appeared in any other mammalian lineage.  Currently, few theories explaining the transition to specialized arm-swinging locomotion in primates have been proposed, and none of these provide an experimental framework by which to approach this question.  My dissertation focuses on the mechanics of below-branch quadrupedalism, which is a form of suspensory locomotion commonly seen in primates and other mammals that requires few anatomical modifications.  The goal of my project is to understand the proximate strategies mammals use to adjust mechanically to below-branch quadrupedal locomotion and then determine whether below-branch quadrupedal locomotion relates to the ultimate evolution of specialized arm-swinging locomotion in primates. 

To answer these questions, I will collect locomotor data from primates, sloths, and bats during a number of experimental comparisons.  First, I will collect locomotor data from primates walking above and below a runway.  This comparison will determine what aspects of locomotor behavior changes between above and below-branch quadrupedal locomotion.  Next, I will compare the mechanics of below-branch quadrupedal locomotion between primate and non-primate mammals.  This will determine whether there are multiple strategies for adopting below-branch quadrupedal locomotion, or whether all animals are moving in a similar fashion.  Finally, I will compare the mechanics of below-branch quadrupedal locomotion with specialized arm-swinging locomotion in primates to determine if below-branch quadrupedal locomotion may have served as a locomotor precursor to specialized arm-swinging locomotion.   

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AuthorH Gregory

Anne E. Russon
York Univesity

Anne E. Russon

In spring 2012 The Leakey Foundation awarded Anne E. Russon a grant for her long-term study of behavior in east Bornean orangutans (Pongo pygmaeus morio) at the Bendili study area (Kutai National Park). This project focused specifically on orangutan ranging, feeding ecology and spatial cognition. 

Researchers have studied orangutans in the Bendili and nearby Mentoko study areas several times over the last 44 years.  During this time their habitat has undergone drastic changes, including commercial logging incursions, severe droughts and massive forest fires. In the report below Russon describes some of her team’s findings, including how intra-site comparisons of activity budgets and travel distances provide insight into how these orangutans coped with this series of habitat changes. 


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AuthorH Gregory
CategoriesResearch Report

It is with profound sadness that we share with you the passing of Brad Goodhart, the devoted husband of the Foundation's Grants Officer Paddy Moore-Goodhart. 

Brad Goodhart and Paddy Moore-Goodhart on one of their many adventures.

Brad Goodhart and Paddy Moore-Goodhart on one of their many adventures.

Brad had an enduring love for Africa's people and nature, having led over 100 tours of East Africa over the past 35 years. He was a Board Member of the African Orphans Foundation where he helped coordinate fundraising for orphaned girls in Kenya, Tanzania, Uganda and Ethiopia. He taught science, math and English at Bishop O’Dowd High School from 1968-1997, and was most recently teaching at Geyserville High School.

His generous smile, insatiable curiosity, and helpful hand made him a special addition to the Foundation family.

He succeeded in living a full life while inspiring so many others to do the same. Please join us in sending our most sincere condolences to Paddy and her family.

A celebration of Brad's life will be held at 2:00pm on Monday, January 19 at Villa Chanticleer in Healdsburg, California. 

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AuthorMeredith Johnson
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Over the next few months we will be introducing you to Leakey Foundation grantees from our Fall 2014 granting cycle. Our first featured grantee is Alia Gurtov, PhD candidate from the University of Wisconsin, Madison. Her project is entitled "Dental microwear analysis of Early Pleistocene hominin foraging seasonality." 

Alia Gurtov in Rising Star Cave

For our Early Stone Age predecessors in eastern Africa the changing of the seasons meant a profound shift in the quantity and distribution of food and water. Around 2 million years ago at Olduvai Gorge, Tanzania, the global trend toward increasing aridity had begun, and rainfall was limited to a few short months of the year, much as it is today. The savanna grasslands spread to the detriment of tropical forests and the biome they supported. At the same time, the evidence for meat eating in the Olduvai archaeological record became stronger, with more prey animals preserving butchery evidence than ever before. Under these new ecological conditions, the foraging strategies that our ancestors employed provide critical insights into the process of becoming human. Did Early Stone Age meat foraging vary seasonally? If so, did those activities overlap in time and space with the saber toothed cats that occupied the top of the food chain?

Alia Gurtov, MNI analysis, National Museum of Dar es Salaam, Tanzania

By looking at the microscopic dental abrasions caused by chewing, I have shown that it is possible to determine in which season an assemblage of modern eastern African impala died. With the support of the Leakey Foundation, I will use dental microwear analysis to study the season or seasons of death represented by prey animals at Olduvai archaeological sites. I will compare these seasonal mortality profiles to those produced by contemporaneous carnivores at Olduvai and modern Hadza hunter gatherers in Tanzania. Together, these data will help to answer our questions about Early Stone Age behavioral flexibility as seen through foraging adaptations to a changing and challenging environment. 

More information:

National Museum of Dar es Salaam
The Olduvai Paleoanthropology and Paleoecology Project

Alia Gurtov at Olduvai

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AuthorH Gregory

On December 6th The Leakey Foundation’s Board of Trustees convened for our Fall 2014 Granting Session. The Board unanimously approved the twenty-five research grants our Scientific Executive Committee presented as recommended for funding.  

Here are a few numbers from our Fall 2014 Granting Cycle:

  • There were 75 research grant applications
  • 40% were categorized as behavioral, 60% were paleoanthropology
  • Over 400 reviews were submitted to our grants department during this cycle
  • Of the 25 approved grants, 11 were submitted by PhD candidates

We would like to congratulate all of our new grantees, and we look forward to sharing news and information about them and their research along the way! 

Here are The Leakey Foundation's Fall 2014 Grantees:

Thure Cerling, University of Utah:  Stable isotopes of fossil primates in Kenya

Naomi Cleghorn, University of Texas, Arlington:  Investigating a rare Early Later Stone Age site at Knysna, South Africa

Constance Dubuc, New York University:  Male-male competition, sexual dimorphism and alternative reproductive strategies in a non-human primate: A morphological approach

Alexander Georgiev, University of Chicago:  Male oxidative stress and female mate choice in rhesus macaques

Michael Granatosky, Duke University:  Gait mechanics of inverted walking: Implications for evolution of suspensory behavior

Alia Gurtov, University of Wisconsin, Madison:  Dental microwear analysis of Early Pleistocene hominin foraging seasonality

Andrew Halley, University of California, Berkeley:  Determining the embryonic origins of human and primate encephalization

Amanda Lea, Duke University:  Effects of social conditions on DNA methylation and immune function

Fredrick Manthi, National Museums of Kenya: Investigation of new Pleistocene sites in the Turkana Basin, Kenya

Emily McLean, Duke University:  Direct and indirect genetic effects on social behaviors in baboons

Armand Salvador Mijares, University of the Philippines:  The 2015 archaeological excavation of Callao Cave, northern Luzon, Philippines

Elizabeth Moffett, University of Missouri:  Birth and its effects on anthropoid pelvic shape and integration

David Pappano, Princeton University:  Dynamic network analysis of gelada herding and movement

Marta Pina, Institut Català de Paleontologia Miquel Crusafont:  Hindlimb mechanical properties in Miocene apes: Origins of human locomotion

Samantha Porter, University of Minnesota, Twin Cities:  Investigating cultural transmission across the MP-UP transition in western Europe

Shelby Putt, University of Iowa:  Investigating the co-evolution of language and toolmaking: An fNIRS study

Rhonda QuinnSeton Hall University:  Refining paleosol isotopic evidence from Omo-Turkana hominin environments

Michael Rogers, Southern Connecticut State University:  The Oldowan-Acheulian transition at Gona, Ethiopia: Archaeological and geological studies

Clara Scarry, University of Texas, Austin:  Evolution and maintenance of male cooperation among tufted capuchin monkeys

Gabriele Schino, Istituto di Scienze e Tecnologie della Cognizione, C.N.R.:  The emotional basis of primate reciprocity

Nicole Squyres, Johns Hopkins University:  Morphological variation in the distal femur of modern humans and fossil hominins

Adam  Sylvester, University of Glasgow:  Reconstructing walking kinematics from femoral condyle curvature in fossil hominins

Maura Tyrrell, University at Buffalo, State University of New York:  Effect of competition on male coalition patterns in crested macaques

Sarie Van Belle, University of Texas at Austin:  Paternity and kinship in socially monogamous saki and titi monkeys

Brian Wood, Yale University:  Stone tools as digging implements: Archaeological, energetic, and biomechanical implications


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AuthorH Gregory

May 2014 (dry season): Geladas come off the cliffs, where they sleep at night, and regroup at the top. They often take an hour or so to socialize and rest before heading off to forage. Pictured (left to right): graduate student Morgan Gustison; field assistant Esheti; field manager Megan Gomery. Photo by E. Tinsley Johnson.

In the spring of 2013 Elizabeth Tinsley Johnson, PhD candidate from the University of Michigan, was awarded a Leakey Foundation research grant for her project entitled "A test of the vocal grooming hypothesis in the gelada." 

Geladas (close relatives of baboons) are exceptionally unique primates that are only found in the highlands of Ethiopia. What makes them unique? First, they are the only primates in the world that eat primarily grass, which means they spend a lot of time foraging – which sometimes comes at the expense of socializing. Maintaining social bonds is a critical part of gelada life, because they live in large, complex social groups. For females, in particular, the ability to maintain ties with other females in their unit is crucial for maintaining unit cohesion. Geladas are also unique in that they are exceptionally vocal primates, leading some researchers to speculate that the function of their constant chatter is to make up for lost grooming time. If true, the so-called ‘Vocal Grooming Hypothesis’ (e.g., Dunbar 1996) carries implications for how, and why, human language evolved.

May 2014 (dry season): A close-up of a family unit grooming (and playing) in the morning. Females spend roughly 20% of their waking hours grooming one another, a behavior that is critical to forming and maintaining social bonds with other members of their unit. Photo by E. Tinsley Johnson.

For the last year (Oct. 2013-Oct. 2014), graduate student Elizabeth Tinsley Johnson has been studying geladas in the Simien Mountains National Park, Ethiopia. Her research aims to understand how female geladas maintain social bonds and the potential benefits these relationships carry. In particular, Tinsley Johnson is interested in the potential role that vocal contact plays in navigating social relationships. To this end, she has collected climatological, demographic, behavioral, and hormonal data on ~45 adult females across 12 social units. Now back at the University of Michigan, Tinsley Johnson will spend the next year analyzing her data and presenting her results to professional conferences and in journal publications.

July 2014 (rainy season): A large band of geladas spends the last minutes of daylight foraging before heading back down to the safety of the cliffs to sleep. Photo by E. Tinsley Johnson.

September 2014 (rainy season): Researchers from the University of Michigan’s Gelada Research Project wait at the top of a sleep site for the geladas to come up for the day. Photo by E. Tinsley Johnson.

September 2014 (rainy season): Graduate student Elizabeth Tinsley Johnson recording the behaviors and vocalizations of female geladas as the band forages during the day. Photo by J. C. Beehner.

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AuthorH Gregory

Paco Bertolani, PhD Candidate
University of Cambridge

The Tshuapa-Lomami-Lualaba area (TL2) lies at the eastern edge of the bonobos’ species range in the Congo basin. In what eventually led to the creation of the TL2 Project, Terese and John Hart organized extensive surveys of TL2 starting in 2007. They confirmed the presence of bonobos in this area, estimating a population of over 10,000 individuals. This relatively pristine, remote habitat had the potential to be an area of extraordinary importance for the future of bonobos.

In a Leakey Foundation research grant awarded in spring of 2011, Paco Bertolani proposed a pilot study to assess the feasibility of establishing a long-term site for bonobo behavioral research and conservation in TL2. He and his team would conduct surveys in search of bonobo traces. This would include detailed mapping of the study area as well as the collection of fecal samples for genetic analysis and surveying the health of the bonobos. They would also monitor signs of hunting and other human disturbance in collaboration with TL2 Project staff.

In the report below, Bertolani summarizes the results of his team’s findings, including his assessment of the feasibility- and riskiness- of establishing a long-term bonobo research site in TL2 where poaching is a serious problem.



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AuthorH Gregory
CategoriesResearch Report

Young blue monkey

Though the wild blue monkey (Cercopithecus mitis) has a social structure of one-male social groups, this organization can be somewhat dynamic. Resident males do not always have a reproductive monopoly over the females, and non-resident (bachelor) males may have a higher reproductive success than one might expect.

Su-Jen Roberts

 

Su-Jen Roberts, PhD candidate from Columbia University, was awarded a research grant in spring of 2012 for her project to assess what variables drive variance in reproductive success in wild blue monkeys. The report below describes how Roberts used DNA analysis to assign paternity to the study population in the Kakamega Forest of Kenya.  She then combined these results with long-term observational data in order to better understand how variables such as female reproductive synchrony or the number and proximity of competitor males affect the reproductive success of resident and bachelor males.   

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AuthorH Gregory
CategoriesResearch Report

Oliver Paine testing specimens on the Kudu Hill transect.

Recent studies have suggested that C4 plants played a larger role in early hominin diets than previously believed, thus making a systematic effort to determine the costs and benefits of C4 plants for hominin consumption that much more important in helping to model early hominin dietary behavior. 

The following is a short update from Leakey Foundation spring 2014 grantee Oliver Paine, University of Colorado at Boulder, who recently completed the first of two trips to the Cradle Nature Reserve (Cradle of Humankind World Heritage Site, South Africa) where he and his team are performing nutritional and mechanical analyses of C4 and other plants in savanna microhabitats across seasons. We look forward to hearing from him again soon.  

 Left to right: Dr. James Louden (East Carolina University), Alex Cowper (CU Boulder), Oliver Paine, Dr. Amanda Henry (Max Planck), Abigail Koppa (Stony Brook), and Jen Leichliter (CU Boulder)

As always, the dry season in the South African Highveld is remarkable with regard to how little palatable food seemingly exists on the landscape. My research partners and I are always amazed by the fact that herbivorous fauna, both large and small, are able to eke out an existence during this time. As such, our collections were precisely what we had expected: plenty of dormant grasses and forbs. However, there were pockets of green vegetation scattered about  and, in particular, around our wetland transects. Additionally, some tree species, such as Searsia (Rhus) lancea, were fruiting in parts of the reserve.

Impala on one of the burned areas

 
The most significant unexpected hurdle we faced was the fact that a month prior to our arrival, the reserve experienced a massive veld fire that charred roughly half of its vegetation. Luckily, only one of our transects was significantly damaged but the "moonscapes" that surrounded us as we drove through the reserve were eerie at times. Such is the nature of fieldwork!

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AuthorH Gregory
CategoriesFrom the Field

The population of white-faced capuchin monkeys (Cebus capucinus) in the Sector Santa Rosa (SSR) of the Area de Conservación Guanacaste in northwestern Costa Rica offers a unique opportunity to model how landscape variability affected selection on early hominins.  This species shows many anatomical and behavioral convergences with great apes and humans, and they thrive in a broad range of environmental conditions, including the SSR, which could be considered a microcosm of early hominin environments.

In fall of 2010 Fernando Campos, PhD candidate at the University of Calgary, was awarded a Leakey Foundation research grant for his comprehensive examination of the effects of environmental change on this population of capuchin monkeys.  For this project Campos combined behavioral data collected over a period of 18 months with long-term census and demographic data, satellite imagery and genetic sampling. He summarizes his principle findings in the report below. 

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AuthorH Gregory
CategoriesResearch Report

Simone Dagui Ban

Baldwin Fellow Simone Dagui Ban is a PhD student from the Félix Houphouët Boigny University in Côte d’Ivoire. Following the 2010-11 election crisis that made studying in her home country impossible, Ban was given the opportunity to study at the Max Planck Institute for Evolutionary Anthropology for one year.  She was awarded her first Franklin Mosher Baldwin Memorial Fellowship in the spring of 2013 so that she could return to Leipzig to continue her studies. Ban is now a second year Baldwin Fellow and plans on completing her PhD studies at Max Planck in December 2014. She will then be the first female in her country to have earned a PhD in primatology. 

Ban studies the ecological intelligence of chimpanzees, specifically the search strategies and memory skills they need to acquire ripe fruit.  She hopes to build on previous studies to gain further insight into what chimpanzees remember about feeding events (location, abundance of fruit, emotional state, etc.) and how these memories affect their ability and decision to revisit fruiting trees. The following is the abstract from her first paper published in the journal Animal Cognition:

The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Ta ̈ı National Park, Coˆte d’Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females’ approach distance was measured from their last significant change in travel direction until the moment they entered the tree’s maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the pos- sibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees. 

Click here for the full article.

To learn more about the Franklin Mosher Baldwin Memorial Fellowship click here

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AuthorH Gregory
CategoriesJournal Article

In spring of 2013 Philip A. Slater, PhD candidate at the University of Illinois, was awarded a Leakey Foundation research grant for his project entitled "Planning and technological organization in the Kenyan MSA and LSA."  The following is a short update on his progress.

Small and intentionally dug hole that contained about 550 artifacts. The people at the site (~94,000 years ago) appeared to have dug a hole and swept up their mess - small sharp shards of glass from resharpening and shaping various types of tools.

My dissertation research, supported in part by The Leakey Foundation, focused on the long-term changes in stone tool technology that accompanied the evolution of modern humans in East Africa over the past 200,000 years. More specifically, I investigated the Middle (MSA) to Late Stone Age (LSA) technological transition and the adoption of standardized ‘blade’ technology during the LSA (≤50,000 BP). In order to assess levels of standardization I used a combination of typological classification and quantitative morphometrics to analyze obsidian artifact assemblages from three archaeological sites in Kenya’s central Rift Valley.

I found evidence for the systematic curation of late MSA artifacts, which contrasts with the systematic production of standardized LSA artifacts. Tools from MSA assemblages typically have long and complex use-lives, with repeated sessions of resharpening or reshaping maintenance. In contrast, tools from LSA blade assemblages tend to have short use-lives with very few bouts of resharpening. This tradeoff in longevity was counteracted by higher rates of production with standardized components that replaced used tools, rather than resharpening them. I also used scanning electron microscopy of use-wear patterns on individual artifacts to analyze their functions. This analysis provided independent evidence for the long use-lives of some classes of late MSA artifacts, such as points and scrapers, and shorter use-lives for LSA blade tools, most specifically microliths.

Some points (most likely for hunting spears) we found during the excavation

Together, these data provide robust evidence for evaluating the role of technological planning in the evolution of modern human adaptations. By standardizing and compartmentalizing the different production stages of blade tools, LSA knappers were able to more efficiently use their raw materials, time and energy. This technological efficiency is a clear expression of enhanced planning capacities in LSA humans, and provides support for subtle, but significant, advances in cognition during the late MSA. I plan to complete the writing of my dissertation by May 2015 and to publish multiple articles on different facets of MSA and LSA technological organization soon after. 


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AuthorH Gregory

Anne E. Russon and her team have been collecting field data on east Bornean orangutans (Pongo pygmaeus morio) at the newly established Bendili study area (northern border of Kutai National Park) since January 2010. Russon has been awarded two grants by The Leakey Foundation for her study of the ranging behavior and diet of this population, which due to the harsh environment is considered to be the extreme of orangutan adaptation. 

'Our' adult female in our Kutai National Park study area.  Photo shows her (Putri) with juvenile son (Pur) and new infant (no name yet, ca 1-2 mo old, against her belly hidden under her right hand).  Looks like Pur is trying to touch the baby. Mom's hand gently stops him. - Anne E. Russon   
Photo Credit:  Purwo Kuncoro

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AuthorH Gregory
CategoriesFrom the Field

Erella Hovers
Institute of Archaeology, Hebrew University of Jerusalem

Excavation of ‘Ein Qashish

Traditionally, studies of Levantine (eastern Mediterranean) Middle Paleolithic sites have focused on caves, and so exploration of the open-air ‘Ein Qashish site presents a novel opportunity to expand our understanding of the behavioral dynamics of Middle Paleolithic hominins (modern humans as well as Neanderthals) in the region.

In the spring of 2011 Erella Hovers was awarded her fifth Leakey Foundation research grant for her project entitled “Exploring ‘Ein Qashish, a Middle Paleolithic site in northern Israel.” She proposed large-scale excavations at the newly discovered site so that her team could understand the site formation processes, test for spatial differences in the distribution of lithic and faunal remains, and characterize modes of site utilization. Finally, they would begin to reconstruct the ecological environment of ‘Ein Qashish.

In the report below Hovers briefly describes some of her team’s findings.  In addition, you may find the four papers that have been published on the ‘Ein Qashish research in Quaternary International by clicking here   

View of skull base and vertebrae within the depositional context

 

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AuthorH Gregory
CategoriesResearch Report

Leakey Foundation grantee Alexandra Uhl, PhD candidate from the University of Tübingen in Germany, reports from the StEvE Conference.

EvE is a semester seminar series at the University of Tübingen with speakers who talk about their research in Evolution and Ecology. The StEvE conference is organized within the EvE for Students… So St(udents) and EvE = StEVE.  

Each year StEvE is organized by a different department at the University of Tübingen, and this year it was organized the Johannes Krause and Alexander Herbig of the Paleogenetics Department. They did a great job, and everything ran smoothly. We had two days of very interesting talks from a wide range of research fields. Most of the talks were on PhD research, but a few were also on MA research. There were drinks and meals where everyone could mix and discuss the research.

The conference was inside the Paleontology Museum of Tübingen, which was fun in itself. This picture is from the poster session. (You can see some huge vertebrae!) Note the Leakey logo on my poster (lower right corner next to my contact info). 

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AuthorH Gregory
CategoriesFrom the Field

"These are some of the non-adult crania we scanned at Universität Tübingen. That's our CT scanner in the background. We also did DNA analysis on the teeth from these individuals."

In the spring of 2014 The Leakey Foundation awarded Alexandra Uhl, PhD candidate from the University of Tübingen in Germany, a research grant for her project entitled "Sex determination in geographically and ontogenetically diverse samples." 

My research looks at sexual dimorphism (differences between males and females) in the bony labyrinth, which is the rigid outer wall of the inner ear, across different modern human populations and different age groups. When human skeletal remains are found in an archaeological context, it can be difficult to estimate the sex of the individual if the bones and features that are sexually dimorphic, such as the pelvis and skull, are incomplete or broken. However, the bony labyrinth is housed in the petrous part of the temporal bone called the petrous pyramid, the best preserved area of the human skeleton and the most often found at archaeological sites and crime scenes. The petrous portion can even survive cremations. Since previous research on adult Europeans has found sexual dimorphism in the bony labyrinth, my research will explore this in world wide populations and different age groups.

Getting one individual ready for a batch scan at Witwatersrand.

Non-adults are extremely difficult to estimate sex for because they have not yet gone through puberty, which would make their bones more female or male. Thus, a technique that can be used on juveniles for sex estimation is extremely exciting, and since the bony labyrinth is fully formed in utero (before birth), sexual dimorphism should be present no matter what age an individual is. We plan to also apply the technique to Neanderthal and Upper Paleolithic specimens, for which sex estimation is also difficult due to robust features.

In September 2014 I went to the University of Witwatersrand in Johannesburg, South Africa to collect 58 scans of Zulu skulls from the Dart collection. I also measured the pelvis and post crania. In November 2014 I will go to Pennsylvania State University to make 40 scans of Oneota (pre-contact Native American) skulls and also measure the pelvis and postcrania. I also plan to do sex estimation using DNA analysis. I am working with a German skeletal collection At the University of Tuebingen, Germany as well.

Batch scan at Witwatersrand.  "This is how we saved time scanning. You carefully stack 2-3 individuals in the tube and set the scanner to do a batch scan. This way you don’t have to come back every 20 minutes to switch skulls, instead just every 40-60 minutes." 

A Zulu skull from the Dart Collection at Witwatersrand. Female, age 20.

Alexandra Uhl touring the Cradle of Humankind with Francis Thackeray

Alexandra Uhl at the Cradle of Humankind

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AuthorH Gregory

The Leakey Foundation is participating in the Amazon Smile program which will donate .5% of the purchase price of all eligible products that you buy if you sign up to support The Leakey Foundation. This is a simple way to support scientific research and science outreach at no cost to you! If you're an Amazon customer just follow these easy steps:

We appreciate your support very much, and if you're already supporting us with Amazon Smile, we thank you!

Leakey Foundation grantee Caitlin Barale studies wild geladas in Ethiopia.

Leakey Foundation grantee Caitlin Barale studies wild geladas in Ethiopia.

Another way that you can lend your support to the funding of human origins research and primate studies is to join The Leakey Foundation, and we now have a way to accept recurring donations! If you're considering becoming a member, please sign up to become a sustaining member. Your donation will be spread out in monthly installments rather than as a lump sum. With your support we can continue funding important research on our evolution, behavior and survival.

Posted
AuthorMeredith Johnson

Leakey Foundation grantee Isaiah Nengo (spring 2014) has recently returned from the field with exciting news!

Isaiah Nengo at work in the Lake Turkana Basin

Plio-Pleistocene sediments of the Lake Turkana basin have provided numerous fossils key to our current understanding of the origin and evolutionary history of the hominid lineage in Africa.  Scattered within the vast Plio-Pleistocene deposits are small Miocene sites documenting the evolutionary history of the ape lineage preceding and leading to the emergence of hominids.   I have teamed up with Ellen Miller of Wake Forest University on a field research program at the early Miocene of Buluk on the eastern side of Lake Turkana and on the southern side of the Lake at the middle Miocene of North Napedet.

Excavating a specimen

The Koobi Fora Research Project first surveyed the Miocene at North Napedet in 1990 and 1992.  A single canine belonging to a carnivore was recovered.  There was no further work at Napedet until the survey I conducted in February 2013, assisted by a Koobi Fora Research Project team. We successfully relocated the site, obtained GPS coordinates for two areas with dense bone concentrations, and collected a few mammal fossils.  The two weeks I just spent at North Napedet in August/September 2014 marks the first systematic collection of fossils from the Middle Miocene localities at Napedet.  Mr. Gordon Getty, through a Leakey Foundation grant, funded the fieldwork, while the Turkana Basin Institute and the Foothill-De Anza Foundation provided logistic support.

Isaiah Nengo and the team

I arrived at the Turkana Basin Institute Turkwel Facility on August 28, 2014.  The following day, August 29, I departed Turkwel and set up field camp accompanied by a 6-member crew.  The team members, all Kenyans, were four locals John Ekusi, Abdullah Ewoi, Akai Ekes, Bernard Ewoi, and the field manager Cyprian Nyete. We spent a total of 15 days at Napedet, arriving back at TBI Turkwel on September 13 and were able to recover a total 38 new specimens.  The new specimens include a canine of a hominoid, two maxillary fragments of a rare middle Miocene hippopotamid, and two remarkably well preserved fossil fruit. The most spectacular discovery was that of a complete and beautifully preserved cranium of an anthropoid juvenile.  

The study of the cranium is underway.  The study team members are John Fleagle, SUNY Stony Brook, Chris Gilbert, CUNY, New York, and Ellen Miller, Wake Forest. Fred Spoor, University College, London, has generously agreed to assist with the CT-scanning.  We plan to resume fieldwork at Napedet next summer to excavate the area where the cranium was discovered and to survey for new areas of bone concentration.  We also expect to launch, starting the summer of next year, a joint field school with Turkana Basin Institute to excavate two giant bone beds at Buluk.

Isaiah Nengo is a professor of anthropology at De Anza College. He earned his PhD at Harvard University and did his undergraduate work at Nairobi University in Kenya. His primary focus is to document origins of the ape lineage, the evolutionary roots of the human lineage, and the adaptive emergence of human bipedalism in the fossil record of the Miocene (approximately 25 to 5 million years ago) in Africa. He is the recipient of multiple Leakey Foundation grants.

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AuthorH Gregory