Periodic Reporting for period 2 - NGIPALAJEM (The evolutionary landscape of modern human origins in Africa)
Reporting period: 2023-04-01 to 2024-09-30
Our species, Homo sapiens, evolved in Africa. Yet, understanding why we evolved, from whom, and how our evolution was shaped by climate and environmental change remains elusive.
The oldest fossils that have unique features present in all modern humans are found in Africa between 300,000 and 200,000 years ago, which also corresponds to the period when genetic data indicates all living humans last shared a common ancestor. But we also know that the long-standing ‘Out of Africa model’ as originally formulated no longer holds. To understand our origins we need to go beyond the time when our species had already evolved – back through time to 700,000 years ago, when our lineage was evolving independently from that of the Neanderthals, and even beyond that time, when the ancestral population we share with Neanderthals had begun its evolutionary trajectory separate from other hominins. We know amazingly little about human evolution then - fossils of this age in Africa are very rare, those that exist are strikingly different from each other, and determining their age with certainty is extremely challenging. Yet, it is only by trying to build our evolutionary archive in Africa for the last million years that we will understand how our origins are linked to the major climate and environmental shifts that took place then, and how our own evolution impacted the ecosystems on which we depend.
Contributing to this understanding is the core aim of the Ngipalajem project – to find new hominin fossils, contextualise them ecologically and chronologically, and through their study, fill some of the missing pages in our story.
To do this, we work in Turkana in northern Kenya, where dozens of hominin fossils from 4 to 1.3 million years have been found, as well as two of the earliest known modern humans in the world, dating to ~230,000 years ago. Since palaeontological work in Turkana began in the late 1960s, scientists thought that sediments (and thus fossils) of the last million years were not preserved. Our work has shown this is not the case – not only sediments of this age do exist, but are also rich in fossils, including hominins. Our project is discovering new fossils from this critical period in time – of both hominins and fauna, establishing their geochronological framework, and through their study, attempting to provide new insights into our evolutionary past.
The oldest fossils that have unique features present in all modern humans are found in Africa between 300,000 and 200,000 years ago, which also corresponds to the period when genetic data indicates all living humans last shared a common ancestor. But we also know that the long-standing ‘Out of Africa model’ as originally formulated no longer holds. To understand our origins we need to go beyond the time when our species had already evolved – back through time to 700,000 years ago, when our lineage was evolving independently from that of the Neanderthals, and even beyond that time, when the ancestral population we share with Neanderthals had begun its evolutionary trajectory separate from other hominins. We know amazingly little about human evolution then - fossils of this age in Africa are very rare, those that exist are strikingly different from each other, and determining their age with certainty is extremely challenging. Yet, it is only by trying to build our evolutionary archive in Africa for the last million years that we will understand how our origins are linked to the major climate and environmental shifts that took place then, and how our own evolution impacted the ecosystems on which we depend.
Contributing to this understanding is the core aim of the Ngipalajem project – to find new hominin fossils, contextualise them ecologically and chronologically, and through their study, fill some of the missing pages in our story.
To do this, we work in Turkana in northern Kenya, where dozens of hominin fossils from 4 to 1.3 million years have been found, as well as two of the earliest known modern humans in the world, dating to ~230,000 years ago. Since palaeontological work in Turkana began in the late 1960s, scientists thought that sediments (and thus fossils) of the last million years were not preserved. Our work has shown this is not the case – not only sediments of this age do exist, but are also rich in fossils, including hominins. Our project is discovering new fossils from this critical period in time – of both hominins and fauna, establishing their geochronological framework, and through their study, attempting to provide new insights into our evolutionary past.
This first phase of the project focused on the collection of baseline data, involving both field expeditions and museum work.
Since October 2021, we have undertaken 2 major and 9 short field expeditions to Turkana. The two major field expeditions where to an area we have been working for many years and where we have found 4 new fossil sites – Lokodongot, Kalakoel 3, Ngingolea and Lon’garakak - that date to between 750,000-130,000 years ago. The work focused on studying the geological setting, sample sediments for dating, and complete palaeontological surveys. The geochronological work is not yet complete, as this is a geologically complex area never studied before shaped by tectonics and climate-driven changes in lake-levels. We have completed the palaeontological surveys and excavations, which have resulted in a new palaeontological archive of >4,000 fossils, including ~50 new hominin fossil fragments, of which 12 are major finds. Most of the short field expeditions were to an unexplored area East of the Kerio River in Southwest Turkana. This is a remote place, of extremely difficult access, and which requires crossing a large river during the few days of the year when water levels are sufficiently low and major logistics (it has no roads, drinking water or electricity!). But there we discovered fabulous new sites from 4.2 million years ago to the recent past, including new hominins. Finally, we had a short expedition to Ileret, Northeast of Lake Turkana, to identify the site where the fossil of Guomde was discovered nearly 40 years ago and scope the possibility of opening excavations in the area.
We have also undertaken six study seasons at the National Museums of Kenya (NMK Nairobi) to study comparative materials, at the Turkana Basin Institute (TBI) in Turkana to prepare, catalogue and describe the fossils discovered by our project, and one to the Musée de l’Homme (Paris) to study fauna. Through this work we have built large fauna and hominin comparative datasets, including >400 3D models of hominin and human fossils. We have also begun the detailed description of key fossil specimens, particularly the new hominin remains. Towards this end, I was granted permission last year to temporarily export 19 new hominin fossils to Cambridge for mCT scanning, which we are now in the process of study.
Since October 2021, we have undertaken 2 major and 9 short field expeditions to Turkana. The two major field expeditions where to an area we have been working for many years and where we have found 4 new fossil sites – Lokodongot, Kalakoel 3, Ngingolea and Lon’garakak - that date to between 750,000-130,000 years ago. The work focused on studying the geological setting, sample sediments for dating, and complete palaeontological surveys. The geochronological work is not yet complete, as this is a geologically complex area never studied before shaped by tectonics and climate-driven changes in lake-levels. We have completed the palaeontological surveys and excavations, which have resulted in a new palaeontological archive of >4,000 fossils, including ~50 new hominin fossil fragments, of which 12 are major finds. Most of the short field expeditions were to an unexplored area East of the Kerio River in Southwest Turkana. This is a remote place, of extremely difficult access, and which requires crossing a large river during the few days of the year when water levels are sufficiently low and major logistics (it has no roads, drinking water or electricity!). But there we discovered fabulous new sites from 4.2 million years ago to the recent past, including new hominins. Finally, we had a short expedition to Ileret, Northeast of Lake Turkana, to identify the site where the fossil of Guomde was discovered nearly 40 years ago and scope the possibility of opening excavations in the area.
We have also undertaken six study seasons at the National Museums of Kenya (NMK Nairobi) to study comparative materials, at the Turkana Basin Institute (TBI) in Turkana to prepare, catalogue and describe the fossils discovered by our project, and one to the Musée de l’Homme (Paris) to study fauna. Through this work we have built large fauna and hominin comparative datasets, including >400 3D models of hominin and human fossils. We have also begun the detailed description of key fossil specimens, particularly the new hominin remains. Towards this end, I was granted permission last year to temporarily export 19 new hominin fossils to Cambridge for mCT scanning, which we are now in the process of study.
The Ngipalajem project is challenging – it set out to find new palaeontological sites in a remote area of northern Kenya, describe their geology, date them, discover new hominin and animal fossils, and to study these using state-of-the-art techniques. We have already succeeded in some of these challenges - discovering new sites and fossils within them. However, these discoveries are only the starting point! We are now transforming them into real insights into our evolutionary history. This involves very different strands of work.
We have embarked in an attempt to benchmark the growth of stromatolite communities across the Turkana Basin during the last million years to understand the timing and duration of high lake-level stands and their impact on the environmental history of the basin. We have also built a large 3D library of hominin fossils that will allow us to identify taxonomically our new hominin discoveries and quantify how they fit in our evolutionary history. We are developing novel 3D workflows to reconstruct fragmented and distorted fossils using mCT images, as well as a new method to identify the two African species of warthogs by their teeth, as suids are one of the key animal species changing in size and diversity throughout the period. Finally, we are about to begin a study of the palaeoproteins preserved in the Turkana fossil teeth, which we hope will open a new avenue to understand changes in patterns of ecosystem diversity through time.
In the second half of the project, we expect major results. First, in terms of the publication of the complete description and analyses of the 12 new major hominin discoveries we have made, as well as undescribed fossil hominins in the National Museums of Kenya discovered by Meave Leakey many years ago. Second, in terms of the study of the fauna from the sites of Lokodongot, Kalakoel 3, Ngingolea and Long’arakak, which will not only greatly increase the number of known palaeontological sites of this age in Kenya, but through their palaeontological and palaeoproteomic study, provide a framework for the evolution of animal communities at the time of our origins. Third, in terms of the geochronology of the basin in the last million years, which will serve as the foundation for interpreting the fossil and archaeological data of our, as well as other, projects. Finally, we hope to return to the difficult sites East of the Kerio River and make new fascinating discoveries.
We have embarked in an attempt to benchmark the growth of stromatolite communities across the Turkana Basin during the last million years to understand the timing and duration of high lake-level stands and their impact on the environmental history of the basin. We have also built a large 3D library of hominin fossils that will allow us to identify taxonomically our new hominin discoveries and quantify how they fit in our evolutionary history. We are developing novel 3D workflows to reconstruct fragmented and distorted fossils using mCT images, as well as a new method to identify the two African species of warthogs by their teeth, as suids are one of the key animal species changing in size and diversity throughout the period. Finally, we are about to begin a study of the palaeoproteins preserved in the Turkana fossil teeth, which we hope will open a new avenue to understand changes in patterns of ecosystem diversity through time.
In the second half of the project, we expect major results. First, in terms of the publication of the complete description and analyses of the 12 new major hominin discoveries we have made, as well as undescribed fossil hominins in the National Museums of Kenya discovered by Meave Leakey many years ago. Second, in terms of the study of the fauna from the sites of Lokodongot, Kalakoel 3, Ngingolea and Long’arakak, which will not only greatly increase the number of known palaeontological sites of this age in Kenya, but through their palaeontological and palaeoproteomic study, provide a framework for the evolution of animal communities at the time of our origins. Third, in terms of the geochronology of the basin in the last million years, which will serve as the foundation for interpreting the fossil and archaeological data of our, as well as other, projects. Finally, we hope to return to the difficult sites East of the Kerio River and make new fascinating discoveries.