From the Field: Wrapping Up a Terrific Season main content.

From the Field: Wrapping Up a Terrific Season

by AMNH on

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Nairobi, Kenya, July 19, 2011

Here is the whole Rusinga team on the last day of field work. Photo courtesy of W. Harcourt-Smith.

So we’re finally back in Nairobi, having packed up camp and driven back the 300-odd miles from Rusinga to the nation’s capital. It was a terrific field season, in many ways the best we’ve had. We had a really fun and motivated field crew and found a lot of wonderful fossils. What more could one ask?

Now begins the hard work of sorting out everything we found. In our case this means working in the National Museums of Kenya’s exquisite paleontology collections in Nairobi. Any fossils found in the country are reposited here, making it an ideal place to conduct comparative work. We’ve been here about a week, and it is still an overwhelming task. I’m not complaining though. It’s a fine position to be in; I’d rather we had too many than too few fossils.

So far we reckon we have about 1,200 specimens or so, which isn’t bad for three weeks’ work in the field. These range from partial skeletons to isolated teeth, and one of the big tasks right now is going through everything, arranging for it to be cleaned and prepared if needed, and then working out which taxon each specimen belongs to. In some cases we can do this to species level, but in other cases it’s very hard, especially if we think we have a new species. Go to 2 or 3 million years ago on the African savannah, and most of the creatures are more or less similar to what you’d see there today. Back in the early Miocene it’s a whole different world, and there are plenty of weird and wonderful animals that have no real analogues today. I love this aspect of the project, but it can make it a lot harder when you’re trying to identify fossils.

It’s still early days, but some fine specimens are emerging from the cleaning and identification process. The primate cranial fragments we found at Waregi have been pieced together, and so far we have a pretty decent palate of a small-bodied creature called Limnopithecus. It’s a relative of Proconsul, but we’re not sure how close. New specimens like this are therefore extremely important for helping to work that out. The carnivore jaw from Kaswanga has turned out to be a remarkable specimen. It’s got some of the most worn-down teeth I’ve ever seen, meaning it came from a very elderly individual.

Two men seated at a work table with a microscope and other tools, bent over specimens.
Dental microwear expert Peter Ungar, from the University of Arkansas, and my graduate student Brian Shearer are shown here hard at work on Proconsul teeth. Photo courtesy of W. Harcourt-Smith.

We’ve also got an exciting new aspect of the project underway. A few days ago a world expert on dental microwear, Peter Ungar from the University of Arkansas, flew in to start work on our new specimens. Dental microwear refers to all the littler pits, scratches, and abrasions you see on teeth as the result of eating certain foods. It turns out that there are marked differences between how the teeth of different animals wear down depending on what they are eating. Know what the animals are eating and you can get a better understanding of what the environment was like, as well as know more about how the various animals interacted with it. Peter uses cutting-edge techniques, and for our project he is concentrating on the primates and some of the grazing animals we find (although he’s doing as many of the other animals as possible!) It’s painstaking work, and lots more will be needed to be done back in the lab in the U.S., but the results will be critical for our understanding of the broader paleobiology of Proconsul.

On that note, I better sign off, as there’s a lot to do! Thanks very much for reading the blog over the last month or two. It was great fun giving a small taste of what the paleontological projects on Rusinga are all about. We’ll hopefully be back there next year, so watch this space.