A decade-long project pushes back the prehistoric timeline in Africa by more than 10 million years

Something as simple as grass could fundamentally change the understanding of life in the prehistoric world. Studies published in the journal Sciences Documentation of oldest evidence of local abundance of C₄ East African weeds and how c₄ Grasses and open habitats influenced the development of early apes.

Since 2013, Daniel Pape, PhD, associate professor of earth sciences at Baylor University and an international team of researchers have focused their research on understanding how ancient environments influenced the evolution of early apes in East Africa.

Researchers have often argued that during the early Miocene, between about 15 and 20 million years ago, equatorial Africa was covered by semi-continuous forest and that open habitats with C₄ Grasses did not proliferate until about 8 to 10 million years ago. However, there has been some research that has shown contradictory evidence for this long-held notion. This only study has evidence of C.₄ Herbs in East Africa about 15 million years ago. Peppe and the research team set out to find out if this study was an anomaly or evidence of the true diversity of ecosystems that occurred during the early Miocene.

Determine whether open habitats and C.₄ Plants were more widespread much earlier than originally thought, which would have important implications for understanding the features and adaptations of early apes and why C tropics exist.₄ Grassland and savanna ecosystems in Africa and around the world.

Peppe and a collaborative team of geologists conducted research alongside paleoanthropologists at nine early Miocene fossil site complexes in the East African Rift in Kenya and Uganda.

Known collectively as the Research on Catarrhine and Hominoid Evolution Project in East Africa, or REACHE, the team simultaneously focused on understanding the types of ecosystems that existed in the early Miocene, particularly the prevalence of open environments and C.₄ and how these different environments might influence the development of early apes, such as Morotopithecus.

Research has thrived through the uniqueness of the REACHE project, according to co-author Kieran McNulty, PhD, professor of anthropology at the University of Minnesota, who played a key role in organizing the project.

“Working on the fossil record is a challenge. We discover hints and clues about past life and need to know how it was pieced together and interpreted across space and time. Any of the analyzes in these papers would have made for interesting study, and any one of them would have produced incomplete or incomplete explanations. decisive or incorrect.” “This is the nature of paleontological research: It’s like putting together a four-dimensional jigsaw puzzle, but where each team member can see only a few pieces. By combining these methods, we tap into the strengths of one to support weaknesses or validate assumptions of others, resulting in a synthetic approach that challenges established theories.”

When participants shared information and experiences about geological features, isotopes, plant fossils, and monkeys found at the sites, the bigger picture came into focus. The model was that equatorial Africa was completely forested during the early Miocene.

Moreover, the result of this decade-long research pushes back the oldest evidence of C.₄ Grass-dominated habitats in Africa–and the world–more than 10 million years ago, warrant revised paleobiological explanations of plant and mammal evolution.

“We suspected we’d find C₄ plants in some locations, but we didn’t expect to find them in as many locations as we did, and in so much abundance,” Peppe said. Multiple lines of evidence show that C₄ Grasses and open habitats were important parts of the landscape in the early Miocene and that early apes lived in a wide variety of habitats, ranging from closed canopy forests to open habitats such as grasslands and wooded grasslands.₄ herbs. It really changes our understanding of what ecosystems looked like when the modern African plant and animal community was developing.”

A critical aspect of this work was that the team combined many different lines of evidence — geology, fossil soils, plant isotopes and isotopes, which are tiny plant silica fossils — to reach their conclusions.

“The history of the grassland ecosystem in Africa 10 million years ago has remained a mystery, in part because there are so few plant fossils, so it was exciting when it became clear we had plant groups to add to other lines of evidence,” said co-author Carolyn Stromberg, PhD, professor of biology at the University of Washington.

“Weeds are particularly useful for revealing the history of grassland ecosystems. They can tell us not only the presence of grasses, but also what grasses were present and how abundant they were on the landscape. What we found was exciting and very different from what was the accepted story we used to think of in the tropics, bad₄ Grassland-dominated grasslands have only appeared in the last 8 million years or so, depending on the continent. Instead, both phytolith and isotope data showed that C₄ The dominant herbaceous environments appeared more than 10 million years ago, in the early Miocene, in East Africa.”

This early occurrence of C₄ Grasses and open habitats found in the same sites as early apes also allowed the researchers to assess the types of environments early apes would have lived in, according to co-author Rehab Kinyangwe Ph.D. of the National Museums of Kenya and the Max Planck Institute.

“As a paleobotanist, my first task in any field work is to carry out a vegetation study of the site in question. Then I collect sediments of known geological age, whether absolute or relative dates,” said Kinyangwe. “My job becomes exciting once plant microfossils have been processed and extracted in the laboratory for study through a microscope. This task can take anywhere from weeks to months depending on the number of specimens and the abundance and diversity of plant microfossils. These are weeks/months spent in ancient wild, habitats that are no longer exist.Roaming through ecosystems imagine what kind of animals you are likely to encounter in forests, jungles, and grasslands.”

Most importantly, one of the most advanced early apes, Morotopithecus, was found living in open forest environments with an abundance of grass and relying on leaves as an important component of its diet. This contrasts with long-held expectations that unique traits of primates, such as a straight trunk, arose in forest environments to enable access to fruit resources. These findings are transformative, said Robin Bernstein, director of the Biological Anthropology Program at the US National Science Foundation.

For the first time, by bringing together diverse lines of evidence, this collaborative research team has linked specific aspects of early ape anatomy to subtle environmental changes in their East African habitat, which is now revealed to be more open and less forested than previously thought. Frame New work for future studies regarding the evolutionary origins of monkeys”.