From the Field: Stunning Specimens from Kaswanga and More

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croc-bone
A fossil crocodile bone being excavated as Kaswanga. Photo courtesy of W. Harcourt-Smith.

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, July 2, 2011

So I’m sitting right now at a new locality called Gumba. It’s a beautiful spot—a natural bowl of fossil-bearing exposures overlooking the lake and nearby Mfangano Island. I love coming here, even though it’s not as big or prolific as some of the other places we go. We thought we’d pay it a quick visit to see if there were any decent fossils exposed since last year.

It’s a strange place, totally different from the other localities on the island. We find lots and lots of large animals—extinct rhinos, curious knuckle-walking relatives of horses called Chalicotheres—but very few smaller animals like rodents or primates. So far today we’ve found numerous remains of immense turtles and tortoises, a few pieces of crocodile, and some nice hyrax teeth. The crocodile remains suggest the area must have been fairly wet back in the Miocene. Geologically, Gumba is quite a conundrum. The locality is bounded by fault lines, and it’s hard to tell if it’s older or younger than the other fossil-bearing sites on Rusinga. More fossil finds should help answer that question.

Elsewhere things are ticking along nicely. We’re almost done at the Waregi site. In the last few days more fossil primate remains have been found, which is always exciting. The geologists have also discovered some beautifully preserved fossil root systems. They’ll need a few more days to try and work out what type of trees they came from, but these sort of finds can be hugely useful in helping to reconstruct the ancient environment. At Kaswanga the excavations are producing some stunning specimens. Yesterday a large jaw of a carnivorous mammal called a creodont was discovered deep in one of the excavation pits. We’ve trained some local people to excavate, and they’re currently working on exposing more of it so we can see how to extract it.

We’ve got a lot to look forward to in the next week and a half. On Monday we’ll be visiting a stunning locality on top of the island called Nyamsingula. It has commanding views of the island and a wealth of fossils. Anyone who goes there always wants to return. We also have the Museum’s Science Bulletins crew coming to film us, so expect a blog about that once they arrive. In the meantime, I’m going to give everyone a day off tomorrow. The whole team has worked like crazy for two weeks, and a little rest is much needed. I suspect it’ll be quite fun in camp tonight.