Blogging from west Kenya, William Harcourt-Smith, a research associate in the Division of Paleontology, is directing a 20-million-year-old paleontological site on two islands in Lake Victoria. One of these islands, Rusinga, is best known as the site of the discovery of the first fossils of Proconsul, an early ape. Harcourt-Smith’s multidisciplinary team includes physical anthropologists and geologists, and in addition to collecting fossils, researchers are trying to learn more about the evolutionary events and environmental conditions that may have influenced the emergence of Proconsul and other early ape lineages.
Rusinga Island, Kenya, June 26, 2011
So we’ve been here about a week, and things are going really well. We got to Rusinga in record time, set up camp, and are now hunting for fossils in earnest. The first few days we re-visited a number of localities near camp. The closest is called Kaswanga and is famous for producing a number of partial skeletons of Proconsul in the 1980s. This year we’re scouring the site for every little scrap of bone, irrespective of whether we know which animal it came from. Then we’re mapping them using state-of-the-art laser range-finding technology. This may sound a little odd, but there’s a good reason for it. We’re trying to reconstruct how the site formed, and to find out whether there was any bias in the way animals were preserved, or, for that matter, in which fossils were collected. We call the study of site formation taphonomy, and it’s hugely important if you want to try and accurately reconstruct what the ancient environment was like.
Also at Kaswanga, a new member of the team is excavating out a fossil crocodile skeleton. It was a total mess of exploded bone on the surface, and frankly I wasn’t sure if there would be much there. But he is a fossil reptile specialist, and he’s extremely persistent. He made a great judgment call in deciding to dig down and see what was there. Reptiles can be very useful for reconstructing the ancient environment, and given that our focus has been on fossil mammals up to now, it’s been a joy to have someone who knows what they’re doing with a totally different group of animals.
We’ve also set up two excavations, one at Kaswanga, and the other at a site on the other side of the island called Waregi. The excavation teams are using very precise archaeological protocols, and this is a bit unusual for paleontologists, who usually find specimens and then simply dig them out. Controlled excavations, however, are vital for working out the contextual relationships between the different fossil organisms we’re finding. If, for instance, we find fossil apes and certain fossil plants at the same exact level, we can then say something definitive about the environment the apes lived in.
The rest of the team has been on their hands and knees scouring Waregi for fossils. Two days ago it paid off, as we found some wonderful primate specimens, including a tooth of one of the larger Proconsul species, some beautiful cranial remains of a possible small-bodied ape called Dendropithecus, and a number of teeth that we’re still working on identifying.
That’s it for now. Tune in three or four days from now for the next update and, hopefully, news of lots more fossils.