Sometimes, in the middle of nowhere, an Internet connection is not what one would hope it would be! So there has been a bit of a delay continuing our story about what we do in the field during our paleoanthropological expedition.
We arrived and set up camp on February 4, and the archaeologists arrived on February 12 to set up the excavation. So in a short time, we have already worked in three separate scientific fields—geology, paleontology, and paleoanthropology.
In the Ledi-Geraru field area, we have many different “drainages,” which group large areas of hills and valleys into sections. These are what we call the “exposures.” In an area that we and the local Afar people call the “Lee (Lay) Adoyta” drainage, we have looked for fossils of mammals, fish, reptiles, and hominins (or extinct human ancestors) for a couple of weeks. It is a small area about 1 by 2 kilometers.
Our collection strategy is to have the paleontology crew (seven of us!) survey an area by almost crawling up and down each hill and putting flags next to every bone fragment that they find.
Then we collect the fossils that we can identify to some taxonomic or animal-group level that will give us information about the species, about the group, or about the family. For example, the Bovidae (antelope!) are a family of Artiodactyla (two-toed animals) that are very good indicators of habitat. And the habitat in the past is often quite different from what we see around us today. So, if we find horn cores and teeth, we can identify an animal to a species, such as Connochaetes taurinus (a blue wildebeest). If we find only teeth, sometimes we can identify those teeth to a particular group of Bovidae, such as Alcelaphini or a wildebeest-like creature. This group happens to eat grass and live in more open habitats. Finally, we might find a foot bone such as the astragalus, which we can measure to understand the type of habitat the antelope moved in. So even though we don’t necessarily know the species that donated the astragalus, we can still tell something about the ecology of the ancient region.
After we collect all of the fossils for the day, we come back to camp and rinse the dust off the fossils to gently clean them. If a fossil is in pieces, we glue them back together. We identify each fossil specimen to what it is (femur or leg bone) and what it belonged to (monkey).
When we collect each one of these fossils, we first assign a unique bar code to the specimen, and then take the GPS coordinates of the fossils so that we can map where every fossil comes from on the landscape. This is important for looking at patterns of where species are on the landscape. Each of these identifications is loaded into our database so we can ask questions about many aspects of the fossil area later.
You can see a public version of what this might look like at the Hadar Geoinformatics Database, which is based on Google Earth. To see this information, follow the directions under “Accessing the HGP Geodatabase” at https://iho.asu.edu/research/HGP. You will need to have Google Earth already downloaded on your computer.
We have been looking for fossils every day since we arrived in the field. We now have over 400 localities (regions where we have collected one or more fossils). Every day, we have fun looking for fossils because it is like a treasure hunt—you never know what you might find! We have experts here that are excited to see fossil horses, fossil pigs, fossil giraffes, fossil carnivores, and fossil monkeys. And all of us get excited if we find an ancient human ancestor—a hominin!
Until next time! If we have good Internet, we will let you know more about those horses, pigs, giraffes, and more!