by H. Gregory

Shannon McFarlin

Earlier this fall The Leakey Foundation’s board of trustees, staff and friends had the pleasure of visiting the Center for the Advanced Study of Human Paleobiology (CASHP) at The George Washington University. CASHP is a multidisciplinary research center dedicated to the study of human origins, and lucky for us, students and faculty of CASHP were kind enough to give us an extensive tour of their labs now located in an impressive new facility. Paddy Moore and I also took the opportunity to touch base with current and former Leakey Foundation grantees studying at the center, and so we sat down with Shannon McFarlin, assistant professor of anthropology and director of the Hard Tissue Biology Laboratory at CASHP.

Shannon McFarlin sharing her research with Leakey Foundation trustees.

The Leakey Foundation awarded Shannon McFarlin a Leakey Foundation Research Grant in the spring of 2013 for her project entitled “Growth and life history of wild mountain and western gorillas: Rwanda and Congo.” In this project, she and her team are studying the physical ontogeny or development of wild gorillas in order to get baseline data on how fast mountain gorillas grow to adult size, how they invest in growing and developing, and how this relates to aspects of their behavioral and reproductive maturation.  They are trying to flesh out a comparative framework for understanding human life history evolution by shedding more light on great apes and how their histories vary between species with different diets and social behaviors.

How do you record the growth of a gorilla over time? You measure it! But obviously, this might be a little tricky. "You can't put a tape measure on a mountain gorilla," McFarlin said. That is just not going to work, and so, as is frequently the case in behavioral studies, the researchers have to be creative and multi-talented. For this research, McFarlin and her team use field photogrammetry methods to gather the data.

Photogrammetry is not as complicated as it might sound. In fact, the principle behind the method is quite simple. Take laser pointers separated at a certain distance and place them on a nice, weatherproof camera. When you point the camera at the subject, green dots appear on the subject at a known distance apart. By taking multiple photos of different parts of the body of the subject, you are able to accurately measure it.  

The Leakey Foundation funded the pilot study and the implementation (first year of data collection) in the field. After validating the accuracy of the method at Zoo Atlanta by comparing actual physical measurements (like with a tape measure) with the remotely acquired measurements (photogrammetry), they implemented the method in the field on Virunga mountain gorillas at the Karisoke Research Center in Rwanda. Because these gorillas are almost entirely folivorous (leaf-eating), they represent a dietary extreme amongst the great apes. They are also characterized by earlier ages at weaning, earlier age at first birth and a higher fertility compared to more frugivorous (fruit-eating) western gorillas, and so this population is well suited for testing hypotheses about growth and life histories of great apes.  

As you might imagine, this isn't as simple as pointing the camera and taking a picture. The team had to work out which landmarks on these gorillas they could most reliably identify that would approximate similar measurements you would take from a skeleton, and then there's the thick fur that makes it difficult to find these landmarks." We definitely deal with a fuzzy boundary problem," McFarlin said. In addition, the photographer must know which gorilla postures are best for obtaining accurate measurements as well as which areas of the forest are best suited for data collection.  Because of all the variables, they take multiple photos, and then they use the mean measurement. It turns out this mean is quite accurate. According to the pilot study performed in Atlanta, there is a maximum 5% variation of remote measurements from physical measurements.

Images for assessment of dental eruption status are also collected. 

What has been accomplished? The team has been taking measurements over time on 120 gorillas, half of which are still in the growing stages, and this data collection continues! In fact when we visited GWU, Jordi Galbany, the postdoctoral scientist who takes the majority of the photography for the project, was in the field in Rwanda taking pictures and sending the good ones to McFarlin using semi-reliable internet connections in Africa.

 As a result of the pilot study and initial results from the field, McFarlin and her team were able to acquire an NSF grant to continue data collection an additional three years (total of five) and increase the density of behavioral sampling at Karisoke. As you can see, there is certainly so much information forthcoming from this project, and it is quite satisfying to witness first-hand the results of The Leakey Foundation’s tradition of funding exploratory phases of promising new research projects. We look forward to hearing more!

We would like to thank Shannon McFarlin and her team for taking the time to meet with us! 

The following is a copy of the poster the team presented on the results of this Leakey funded project at this year’s AAPA meeting in St. Louis. Click here to download the full PDF. 

AuthorH Gregory

For our sixth episode we have the first in a collection of stories looking at human behavior and how it’s been shaped by evolution.  Dorothy Cheney and Robert Seyfarth share their research on the baboon mind.    

Robert Seyfarth is a member of The Leakey Foundation's Scientific Executive Committee.

Robert Seyfarth is a member of The Leakey Foundation's Scientific Executive Committee.

Dorothy Cheney and Robert Seyfarth study the communication and social behavior of wild non-human primates.  They received their PhDs from Cambridge University, and since 1985 they have held positions at the University of Pennsylvania. Cheney is a professor of biology and Seyfarth is a professor of psychology.  

In this episode they tell us about their long-term (1992-2008) study of free-ranging baboons in the Okavango Delta in Botswana. As with other primates, kinship and rank are tremendously important to these baboons. However, in this sophisticated society there seems to be a certain attentiveness, perhaps an obsession with other individuals’ relationships, including individuals from other species! Does this behavior help them to form bonds, maintain them, and form strategic alliances with others? Is this similar to how humans create social bonds and alliances? Humans may understand that having close relationships with others can contribute to our ability to reproduce and survive, but does this apply to baboons?  If so, what role does personality play in their survival?

Listen and learn how these field researchers have approached these and other questions about how natural selection shapes the primate mind. 

Dorothy Cheney is a frequent reviewer for The Leakey Foundation's granting program.

Thank you to Robert Seyfarth and Dorothy Cheney.  

This show is a project of The Leakey Foundation. You can help fund this podcast and the research we talk about by making a gift to The Leakey Foundation. If you give now, your donation will be doubled! Click here! 


Robert Seyfarth and Dorothy Cheney’s website
Book:  Baboon Metaphysics
"How Baboons Think (Yes, Think)" New York Times 


Produced by Meredith Johnson
Edited by Audrey Quinn
Original music and scoring by Henry Nagle
Production help from Schuyler Swenson

Sponsors: Being Human ( and the Baumann Foundation
Adept Word Management (

AuthorH Gregory
CategoriesOrigin Stories

María Martinón-Torres studying the Daoxian teeth at the IVPP in Beijing

María Martinón-Torres is a Leakey Foundation grantee from the University College London. She and her team were recently published in the journal Nature for their work in Southern China. She has been kind enough to provide us with her summary and thoughts on the significance of this find.

The discovery of 47 human teeth with unequivocally modern morphologies from a cave in southern China reveals that our species, H. sapiens, was present in Asia much earlier than expected. Dated between 80,000 and 120,000 years, the human fossils recovered at the Fuyan Cave (Daoxian) represent the earliest “fully modern” humans outside Africa.

Prior to this work, the earliest unambiguous evidence for H. sapiens east of the Arabian Peninsula came from Tianyuan Cave (Northern China), Niah Cave (Borneo) and Lake Mungo (Australia), dated to 40,000-50,000 years. In the Levant, the human fossils from Skhul and Qafzeh, dated to around 80,000-100,000 years, have been defined as “anatomically modern," meaning that they are in the root of our lineage but still preserve some primitive features that make them different from current modern human groups. In the same line, paleoanthropologist Tim White employed the expression “on verge of the anatomical modernity but not yet fully modern” to refer to the fossils found in Herto (Ethiopia); with 180,000 years, these represent the earliest hominin fossils known for our species. Thus, The Skhul and Qafzeh fossils have been interpreted by some researchers as evidence of a “failed dispersal,” as an Out of Africa attempt that barely managed to reach beyond the borders of the African continent. In this context, the majority of the scientific community agree that the true Out of Africa succeeded only 50,000-60,000 years ago, when modern human populations were finally able to expand throughout the world, reaching Australia and taking over the European empire from Neanderthals.

However, a minority of researchers have suggested the possibility that not one, but several Out of Africa events may have occurred. These successive migrations would have started earlier, during the first half of the Late Pleistocene and, probably, the first of them would have followed a southern route, through Arabia, instead of a northern one through the Levantine corridor. Most of the evidence they used to support this scenario was based on archaeological and climatic data. However, to verify this hypothesis conclusively, we were lacking “the corpse.” Fossils between the Levant and South East Asia are very scarce, and the lack of a reliable chrono-stratigraphic contexts and/or clear taxonomic identifications has been putting under quarantine all the hypotheses that needed a modern human in Asia more than 50,000 years ago.

One of the most representatives examples of this problem is the Zhiren mandible, also found in Southern China and dated (without unanimous agreement) to more than 100,000 years. According to the researchers that performed the study, the Zhiren sample belongs to H. sapiens, but the preservation of some archaic features has led to different interpretations. Hence, for some researchers Zhiren is the result of the hybridisation of H. sapiens with a primitive population, whereas for other scholars it represents a gracile H. erectus that survived late into the Late Pleistocene.

María Martinón-Torres, Liu Wu, José María Bermúdez de Castro and Wu Xiujie, visiting the Daoxian site last October

But now the quarantine is broken. Daoxian fossils fulfill all the requirements which other sites did not.

1) Their taxonomical attribution to H. sapiens is unequivocal.

Daoxian teeth are fully modern, morphologically closer to late Late Pleistocene or even contemporary populations than to other roughly contemporaneous specimens from Northern China (such as Xiujayao) or other anatomically modern human groups (such as Qafzeh).

2) Their chrono-stratigraphic context is robust.

The stratigraphy of the Daoxian cave is clear and simple. There are four well-defined horizontal stratigraphic layers that appear consistently throughout the 300 m2 of excavated area. Fossils are accumulated in layer 2, together with an abundant mammalian assemblage that includes several extinct taxa and which, as a whole, is typical of the first half of the Late Pleistocene. Layer 2 is sealed by a continuous flowstone (layer 1) that prevents the accumulation of younger sediments below, and which the paleomagnetic study confirms is in situ. This is important because it means that everything found below the flowstone – of particular interest the layer 2 where the human and fauna fossils were found – must be older than layer 1. Thus, the U/Th dating of a stalagmite that grew on top of the flowstone - and is hence younger than all the layers below - provides a minimum age of 80,000 years for all the sediments in Layer 2.  The type of associated fauna together with the dating of some loose speleothem fragments point to a conservative maximum age estimation of 120,000 years.

The discovery of H. sapiens to the "East of Eden" where the mithocondrial Eve was first found opens a fascinating range of hypotheses and scenarios to investigate.

1) If H. sapiens’ origin is African, the Daoxian evidence suggests that H. sapiens left before expected and that there may have been not one but several Out of Africa dispersals. It also means that there are a lot of unresolved questions about the routes of dispersals and the fate/type of interaction that each of these hominin waves went through.

2) While Northern China was settled by more primitive hominins, Southern China was witnessing the arrival and/or evolution of more derived humans. This means that when H. sapiens enters the Asian scene the continent was still inhabited by a different hominin.

3) The find also poses questions about who are the immediate ancestors of current populations. Although the fossil evidence keeps pointing to Africa as the birthplace of anatomically modern humans, we still have to investigate the fate of each of these dispersals. Can be that some current H. sapiens populations are descendants of these early immigrants? Or are we basically descendants of a later exodus through the Levantine corridor? Can be both hypotheses complementary? The genetic evidence has been typically the strongest argument to defend a recent African origin for all H. sapiens.  However, as suggested by Groucutt and his team (Evolutionary Anthropology 24, 2015) it seems that there are at least two scenarios where the genetic evidence is theoretically compatible with an early out of Africa - and even a back-into-Africa - dispersal, through extensive gene flow between African and non-African H. sapiens. These hypotheses, although attractive, pose complex phylogeographic scenarios that are less parsimonious and straightforward to match with available genetic evidence. Still, molecular evidence itself has been changing our evolutionary perspective leading us to consider scenarios, such as the hybridization of H. sapiens and Neanderthals, that were sort of “unthinkable” some years ago, mostly for the geneticists themselves. Hence, it may be the time to think ahead and be creative, time to leave the “comfort zone” and explore alternatives that may be wrong... or may be right. I welcome brave thinking as it is the only way to discover something new.

4) H. sapiens took twice the time to enter Europe that it took to enter Asia. The fascinating coincidence between the arrival of H. sapiens to Europe and the Neanderthal disappearance has been commonly interpreted as evidence of the superiority of modern humans, as their presence would have led to H. neanderthalensis extinction. However, the story may have a radically different reading. If modern humans were already at the gates of Europe about 100,000 years ago, why were they not able to enter until 45,000 years ago?

María Martinón-Torres, Xing Song, José María Bermúdez de Castro, Lui Wu and Wu Xiujie in the Fuyan village at Daoxian

Maybe H. sapiens did not enter because they were not capable of doing so while Neanderthals were there. Was Europe to small for the two of them? For almost half of a million years, H. neanderthalensis had dominated the land of seasons, of changing skies and long winters making of it an impenetrable kingdom for a tropical human. This Neanderthal advantage, however, was also their own executioner. Neanderthal’s story is the chronicle of a death foretold. The merciless and cyclic punishment of the glacial ice ended up decimating a population that was genetically exhausted due to isolation and endless winters. Neanderthals were no longer who they used to be, and only now, H. sapiens saw his opportunity.  

This is only the beginning. I excitedly foresee a scientifically prosperous and creative period when the story of human evolution in Asia will end up intertwining with the mainstream and, in more than one occasion, will pull the centre. 

Click here to read the full article.

Para una versión en español, visita por favor el enlace en la página web del Museo de la Evolución Humana.  

Wu Liu, María Martinón-Torres, Yan-jun Cai, Song Xing, Hao-wen Tong, Shu-wen Pei, Mark Jan Sier, Xiao-hong Wu, R. Lawrence Edwards, Hai Cheng, Yi-yuan Li, Xiong-xin Yang, José María Bermúdez de Castro & Xiu-jie Wu (2015). The earliest unequivocally modern human in South China. Nature.   

AuthorH Gregory
CategoriesJournal Article

Rebecca Miller, principal investigator and director of the Trou Al’Wesse project

Dr. Rebecca Miller (Spring 2015 Grantee), with co-investigators Dr. John Stewart and Dr. Keith Wilkinson, completed this summer’s Leakey Foundation funded field season at the site of Trou Al’Wesse in Belgium. With an enthusiastic and meticulous team of students from the University of Liège, Bournemouth University and Winchester University, as well as two students doing doctoral and Master’s research on paleoecological and geological aspects of the site (Monika Knul, PhD student from BU and Eden Richards from U of W), this season was particularly productive.

Trou Al’Wesse, July 2015

Trou Al’Wesse (“Wasp Cave” in Walloon) is a large cave on the Hoyoux River, a tributary of the Meuse River, located near the village of Modave. It extends back ca. 45 m and connects to a karstic network, with a chimney open to the surface above (formerly filled with deposits excavated in the 19th century that yielded a multiple Late Neolithic burial). Facing southwest, it overlooks the alluvial plain of the Hoyoux. It is situated in the nature preserve owned by Vivaqua, a major Belgian water company with a strong sense of responsibility of cultural and natural preservation. The nature preserve protects many rare and threatened species, including several bat species that hibernate at Trou Al’Wesse. Additionally, they are owners of the nearby Château de Modave, principally 17th century although occupation dates back to the early 13th century. Finally, Vivaqua has been a generous supporter of the Trou Al’Wesse project since the beginning, providing logistical support and assistance in protecting the site.

Preparation of artifacts for recording of 3D coordinates and field data (M6, layer 17a)

The Leakey-funded excavations took place on the cave terrace, focusing on the Middle to Upper Paleolithic transition in units 17 and 16. The chronological focus of the terrace excavations is the MP-UP transition and the Early Upper Paleolithic, from roughly 50,000 to 30,000 BP. In the Pleistocene sequence, this includes units 17 (Mousterian) and 16 (non-archaeological but fauna-rich unit) underlying unit 15 (Early Upper Paleolithic with Aurignacian layers). The principal objective is to study the climatic and environmental context and chronology of human occupations across the MP-UP transition in order to evaluate the factors affecting Neanderthal extinction and the arrival of the first modern humans in northwest Europe. Trou Al’Wesse is the only site in Belgium currently known and one of the rare sites in Northwest Europe with an intact (i.e., unexcavated) stratigraphy covering this period. It is also comparable in cave morphology and size to the eight Belgian sites that have yielded Neanderthal human remains (Engis, La Naulette, Fonds-de-Forêt, Grottes de Goyet, Grotte de Spy in the 19th century and Trou de l’Abîme à Couvin, Grotte Scladina, and Grotte Walou in the late 20th century), suggesting the possibility of discovering new Neanderthal remains in stratigraphic context using modern methodology and techniques.

The goals for the 2015 season were to excavate the Neanderthal occupations with Late Mousterian lithic assemblages in unit 17 and non-archaeological unit 16 on the TAW terrace, collect data to study climatic and environmental variability, clarify the stratigraphic sequence of these units 17 and 16 (previously excavated only in the 1990s in a limited area on the terrace), select bone and charcoal samples for AMS dating of this sequence and collect sediment samples and install dosimeters for OSL dating.

Recording field data, unit 16

The season was quite successful, with unit 17 containing Mousterian layers extremely rich in lithics, fauna, burned bone and charcoal and unit 16 proving to be very complex with several layers that will provide information on climatic oscillations during a phase in which humans were absent from the site.

On the terrace, units 17 and 16 in the M row squares were excavated, starting with M6 (next to M5, which was excavated in the 1990s) to M10, 4 m further from the cave entrance toward the alluvial plain and the Hoyoux River. Half-squares were also opened in M7, M8 and M9 to excavate unit 16. The richness of the Mousterian layers was immediately shown in M6, where, in a single 50x50x25 cm subsquare (M6C), in layers 17a and 17b, more than 700 lithics and bones were recorded in 3 dimensions and many more found during water-sieving to 0.5 mm. Adjacent subsquare L6D was also opened and proved to be as rich. This density necessarily slowed down the expected rate of advancement (initially, our goal was to excavate squares M-N 6-10). At the end of the season (as always!), the top of the Mousterian unit was reached in squares M10 and M9. The Mousterian occupation area extends across the entire zone on the terrace and will be further investigated in spring 2016 and during the summer 2016 field season.

Excavation also continued in a sample column begun in 2014 by M. Knul (BU) and E. Richards (U of W). In 2014, the column had nearly reached the contact between units 15 and 16. Faunal remains here are often much larger, likely due to rapid redeposition and also the probable location of rows up to at least row 6 beneath the former overhang of the cave or even inside the cave entrance. Cryoclastic activity has caused major collapse from the cave face, creating the clast-based Pleistocene deposits on the terrace. Bones identified in the field include woolly rhinoceros, cave bear, horse, reindeer, red deer, arctic fox, mustelids, lemmings, voles, fish and birds.

The Mousterian lithic assemblages from layers 17a and 17b include many tools (sidescrapers, retouched flakes), core fragments, core preparation and reduction by-products and tiny flakes and splinters. The raw materials used are varied: several varieties of fine and medium-grained flint, flint river cobbles, good quality phtanite, fine-grained quartzite. Raw material sourcing is in progress, although the phtanite source is already known to be non-local, in the Ottignies-Mousty region about 70 km WNW (across the Brabant and Hesbaye Plateaux where at least some of the flint is likely to be from, and crossing the Meuse River, where river cobbles would have been available on the river terraces). The lithics are unpatinated and have fresh edges and ridges, suggesting rapid deposition and little post-depositional movement. For subsequent use-wear and residue analysis, none of the artifacts have been handled or processed. Refitting analysis has a good probability of success and will be done after the use-wear analysis.

Verification of field data in the lab at La Limonaderie (our housing at Pont-de-Bonne)

Bone remains are abundant, ranging from fragments to larger elements. Significant amounts of burned bone and charcoal fragments were also present in layers 17a and 17b, although no hearth features have as yet been found.

In unit 16, faunal density varies by layer and analysis of the small mammal fauna in particular will contribute to reconstructing the climatic sequence. Larger fauna so far includes woolly rhinoceros and cervids, identified in the field; faunal analyses are in progress.

In addition to the Leakey-funded part of the project, the excavation of two test pits TP2005 and TP2013 inside the cave was continued. The layer currently reached in TP2005 contains cave bear remains apparently representing a hibernation den. In TP2013, after removal of several phases of backfill from 19th and 20th century trenches and a tunnel, the unexcavated Pleistocene layers yielded an Aurignacian endscraper on a long large blade, indicating that the cave deposits will also contain Aurignacian and very likely Mousterian occupations.

Dosimeters for calibration in post-medieval alluvial deposits in test pit J-K 27-28 (adjacent to borehole from 2012)

Samples will be selected for AMS dating based on stratigraphic layer and identification (e.g., species or bone tool) as well as those directly associated with sediment samples collected for OSL dating. For OSL dating, two specialists working with Johannes Van Der Plicht (Leiden University), Tony Reimann and Christina Ankjaergaard from Wageningen University, came to Trou Al’Wesse and collected sediment samples and inserted dosimeters.

We are now busy with lithic, faunal and geological analyses, sample selection for AMS dating and post-excavation processing and sorting of water-sieved sediments. Over the next several months, we will start to have a clearer picture of the stratigraphic sequence, palaeoenvironmental change and Neanderthal activities during the Late Mousterian. In addition, preliminary talks will be presented at the annual Journées d’Archéologie wallonne (November 19-20, Rochefort) and FNRS “Prehistory” Contact Group meetings in Belgium (December 13, Malines).

Most of the July team, with project archaeologists Yann Waersegers (back row, first from left), Rebecca Miller (second from left) and assistant Marion Plumer (fourth from left)

AuthorH Gregory
CategoriesFrom the Field

Nathan Thompson is a PhD candidate at Stony Brook University who was awarded a Leakey Foundation research grant in the spring of 2014. He and his team were published in this month's issue of Nature Communications, and he has been kind enough to provide us a brief summary of the article. 

Compared to our great ape relatives, humans possess a long and flexible trunk (the part of the body that includes the ribcage, belly, and pelvis). Chimpanzees (as well as other great apes) have a trunk that is typically described as being rigid and block like. The chimpanzee trunk is presumably adapted for a life of tree-climbing, but probably not so great for bipedal walking. This is because during bipedal walking in humans, the ribcage and arms rotate in one direction, while the legs and pelvis move in the opposite direction. You can see this as your arms and legs move in opposite directions when you walk. These opposite rotations are beneficial because they help to conserve a physical quantity called ‘angular momentum’. The angular momentum of the upper body cancels out the angular momentum of the lower body. In humans, this helps to reduce work, and saves energy during locomotion.

But how far back this ability extends into our family tree is a mystery. Though likely present by the time of Homo erectus, early hominins like Lucy (Australopithecus afarensis) display similarities in their ribcage and pelvis to chimpanzees, which suggests they may have possessed an ape-like rigid trunk. A rigid trunk would mean no opposite rotations between the ribcage and pelvis, and would have potentially limited bipedal performance in australopithecines.  

Using a high-speed motion tracking system, we tracked how the trunk of chimpanzees and humans actually moves during bipedal locomotion. To our surprise, we actually found the same amount of motion between the pelvis and ribcage in chimpanzees as in humans. This means that chimpanzee trunks are not actually that rigid. Thus, the ability to move the rib cage to counter the pelvis is present in chimpanzees, and was likely already present in early hominins.

This image depicts pelvis and ribcage rotations during bipedal locomotion. Despite differences in overall motion, there is as much mobility between the pelvis and ribcage in humans as in chimpanzees, suggesting more human-like abilities in our earliest ancestors than previously thought. Credit: Nathan Thompson, Lucille Betti-Nash, and Deming Yang.

The real difference between the two species was in how much they rotated their pelvis. Chimpanzees rotate their pelvis so much that they can’t use their upper body to cancel out angular momentum of their lower body, unlike modern humans. Large pelvic rotations during bipedalism seem to be the primitive condition for non-human primates, so only when human ancestors were able to reduce hip rotation, would they have been able to utilize their upper body to balance angular momentum, and increase walking efficiency. We found that if Lucy were able to reduce her hip rotations to within 150% of the modern human level, she would have been able to rotate her trunk in a human-like way. This would have potentially allowed our early hominin ancestors to decrease work and increase efficiency during bipedal locomotion.

Currently, we are examining what other effects a chimpanzee-like trunk might have on whole-body mechanics of bipedal locomotion. The fact that the basic dichotomy of ‘rigid chimp-like’ and ‘non-rigid human-like’ trunk morphologies don’t hold up, shows us that we have a lot to learn about how our closest relatives actually move. 

What can we learn from chimps swinging their hips? In this Nature Video, we investigate the walking style of our primate cousins, and see what they can teach us about our ambling ancestors. 

You may read the full article in Nature Communications by clicking here


AuthorH Gregory
CategoriesJournal Article

This is a photo of me trying to coax a stick bug off of the Kiahera Formation paleosol we were measuring. Photo credit:  Lauren Michel

Niki Garrett is a PhD candidate from the University of Minnesota. She was awarded a Leakey Foundation research grant in the fall of 2013 for her project entitled "Compound specific paleoecology of Early Miocene hominoids from East Africa." Here is a brief description of her research followed by a report from the field.

I am interested in the relationship between ecological/climate change and primate evolution.  The aim of this study is to obtain detailed paleoenvironmental reconstructions of the Early Miocene (~15-20 Ma) fossiliferous sediments on Rusinga Island, Kenya, in order to clarify our knowledge of the habitats that supported some of the earliest fossil apes. The fossil deposits on Rusinga Island contain some of the richest samples of Early Miocene floral and faunal communities, including many partial skeletons of the putative hominoid Ekembo (Proconsul), fossils from the less well-known catarrhines Limnopithecus and Nyanzapithecus, and three strepsirhine genera Komba, Progalago, and Mioeuoticus. These sites provide an excellent setting to examine the adaptation and diversification of catarrhines and early hominoids, which is a necessary foundation for our understanding of the evolutionary history of all apes including humans.

From left to right (back row): Joshua Siembo, Francis Sina Muteti, Niki Garrett, Collins Ouma Ogongo, and Joel Torgeson.  Front row is a group of local kids from the island.  Taken at the “bovid hill” site. Photo credit:  Lauren Michel

Relatively new molecular proxies will be utilized in this study to augment previous paleoenvironmental reconstructions. Specifically, compound specific hydrogen and carbon isotope analysis of plant leaf waxes (n-alkanes and n-alkanoic acids) preserved in the paleosol and lacustrine sediments. In a C3-only ecosystem, such as those found in the Early Miocene, carbon and hydrogen isotope analyses have the ability to inform our understanding of the density or open/closed nature of the local habitats. This research will provide a paleoenvironmental context for not only this important primate community, but also the extensive mammalian faunal community, as well as to provide documentation of any temporal or spatial changes in habitat during the Early Miocene.

Joel Torgeson (L) and Lauren Michel (R) standing in the middle of the exposed Kiahera Formation paleosol trench. Photo credit:  Niki Garrett

The Leakey Foundation research grant afforded me the opportunity to travel to Rusinga Island, Kenya for a third research trip this past August. First explored in the 1930s by members of the third East African Archaeological Expedition led by L.S.B. Leakey and D.G. MacInnes, fossil deposits on Rusinga Island contain some of the richest samples of Early Miocene floral and faunal communities, including the largest known collection of the primitive hominoid Ekembo (Proconsul). Vertebrate fossils from more than 90 species of mammals are known from the Early Miocene Rusinga Group, which comprises in stratigraphic order, the Wayando Formation, Kiahera Formation, Rusinga Agglomerate, Hiwegi Formation, and Kulu Formation. Renewed research has provided important new insights into the geological and paleoenvironmental context for these deposits including new age constraints for the Kulu Formation (~15-17 Ma) and for older formations (~18-20 Ma). Although decades of research at these sites have produced multiple paleoenvironmental studies, a clear consensus has yet to be reached regarding the ecological context for Rusinga's early apes and other catarrhine primates. Most previous paleoenvironmental research has focused on the highly fossiliferous Hiwegi Formation. The aim of my research is to obtain detailed paleoenvironmental reconstructions for the entire sequence of Early Miocene fossiliferous sediments allowing for documentation of any temporal changes and providing a detailed picture of the habitats utilized by these primates at a critical period in the evolutionary history of hominoids.

Lauren Michel (R) interacting with some of the local kids at the “bovid hill” site. Photo credit:  Niki Garrett

 The primary goal of this trip was to collect lacustrine and paleosol samples from the Kulu and Kiahera Formations for compound (n‑alkane and n-alkanoic acid) specific carbon and hydrogen isotope analyses (CSIA). Compared to previous field seasons, this trip was very quick and involved a relatively small field team. In addition to three Kenyans (Francis Sina Muteti from the National Museums of Kenya, and Joshua Siembo and Collins Ouma Ogongo from Rusinga Island), I traveled with Dr. Lauren Michel (geologist, current postdoctoral researcher at Southern Methodist University, Dallas, Texas) and Joel Torgeson (field assistant, undergraduate at the University of Minnesota).  The six of us spent a total of nine days at various sites around the island assessing the suitability of the formations and deposits for this, and future, research. One of the main factors to be considered when identifying and collecting sediment samples for CSIA are modern contaminants. Sediment samples need to be completely free of modern roots and other plant materials. At some of the Rusinga Island sites, we found this to be nearly impossible making those sites/sediments unsuitable for this specific type of research. On one day in particular, this was a pervasive problem.  We spent one Sunday at multiple sites within two localities, and I was unable to collect a single suitable sample for CSIA. It was noted that the roots appeared to be following the specific layers I was targeting, and no amount of trenching into the hills appeared to uncover sediments without visible modern plant roots - the paleosol sediments were as appealing to the plants as they were to me (although for very different reasons), however the plants got there first!

Joel Torgeson (L) and Lauren Michel (R) standing in the middle of the exposed Kiahera Formation paleosol trench. Photo credit:  Niki Garrett

In the end, I was able to find multiple suitable sampling sites free of modern plants. I collected samples of the lacustrine deposits in the Kulu and Kiahera Formations.  We were also able to identify and describe ~2.3 meters of exposed paleosol in the Kiahera Formation where I also collected CSIA samples. I collected these samples using a protocol that ensures they are not contaminated by other sources of organic matter, such as oils from my hands, sunscreen, or plastic bags.

The next step in this research is to travel to the Lamont-Doherty Earth Observatory (Columbia University, NY) where I will extract and isolate the n-alkanes and n-alkanoic acids from the sediments. Long, straight‑chain (i.e., normal, n‑) alkanes and alkanoic acids are the primary components of the protective waxes that coat the leaf surface of almost all land plants. Because these compounds are extremely environmentally persistent in sediments over geologic time and are resistant to biodegradation, they serve as an exceptional proxy for ancient vegetation in terrestrial or terrigenous sediments. Once these compounds are extracted and purified, I will analyze the abundance and distribution of the alkanes and alkanoic acids, as well as the carbon and hydrogen isotopic compositions of the target compounds. These steps will provide me with information on how “open” or “closed” the local habitats were on Rusinga Island during this period, allowing for a robust evaluation of the variability in the C3 ecosystems inhabited by the Early Miocene catarrhines including the earliest hominoids. 



AuthorH Gregory