You haul sixteen tons....Posted on 17-07-2015 by Lars van den Hoek Ostende
In Anatolia we are not looking for the entire animal, we are just interested in the teeth. Molars consist for a major part out of enamel, the hardest material in the vertebrate body.
Because it is so resistant, it can survive for millions of years. So that is good news for palaeontologists, and even better news is that you can recognise a species by just looking at the molars.
However, that raises the next question. As rodent molars are typically about one to two millimetres long, it is clear that they are not as easily found as, let’s say, a fossil elephant. So how do you find them? The trick lies in recognizing the deposits in which fossils could be found. Usually these are clay seams that are 5 to 10 cm thick. After sampling about one hundred kilos, the clay is washed over a sieve, and the residue checked under a microscope. If that yields some rodent fossils, the hard work begins, and the locality is revisited to collect one or two thousand kilos of clay. Collecting fossil rodents requires some muscle.
The sieve used for this type of work was developed in the 1970s by Mathijs Freudenthal of Naturalis. His model is now used in field campaigns all over the world. The natural museum in Izmir had their own sieve constructed according to this model. A very nice, strong sieve, with some rough edges (I had the cuts in my finger tips to prove that). Having tested that very same sieve the year before, I knew that it needed some additional materials, and the first day we went into Denizli to do some shopping. We needed plastic to dry the sediment on, washing basins to soak the dry clay into a sievable mud, hoses to guide the water and mostly spraying heads to wash the mud through the sieve. We had one, but that was designed to water the garden, and hardly suitable for the business at hand. Moreover, we needed two.
Much to the surprise of myself and my Spanish colleague, our Turkish hosts brought us to a tiny shop, specialised in fire fighting equipment. When they didn’t have what we needed, they directed us to a similar shop, just a block away. Later on, we would see another such shop. Apparently, fire fighting is serious business in Denizli. Our gain, because we got exactly the spraying heads we wanted.
Armed with all this equipment, we drove to our washing place, which was a ideal as it is idyllic. At the foot of a huge cliff of rock of African origin, billions of years old, was the guesthouse. It was built next to a ridge, where only twenty years ago hot water springs were active. Now, the landlord Mustafa pumped water up for guests who visited his thermic baths. Behind the house was a small river on the banks of which we had placed the sieving systems. One of Mustafa’s irrigation pumps ensured that we had water to do our washing, while we could dry the sediment on the fields where he grew his vegetables. Looking back, the place was perfect, not in the least because of the wonderful home cooked meals. But then again, looking back I had nearly forgotten about the score of mosquito bites that covered my legs. Then again, you cannot have it all.
We didn’t haul our sixteen tons. Truth be told, we barely made the two tons. As I wrote the last time, the weather gods had not been favourable, and the rain had kept us from some of our goals. But then again, it was not about the amount of clay, but about finding micromammal molars. Most of these you only find weeks of even months after the field work. But any residue large enough to be screened by the naked eye can be processed on the spot.
I was having a tea, when a shout came from the behind the house. “Gülçin found one!” And indeed, there it was, the first tangible result of all our efforts: a beautiful molar of an extinct hedgehog. Gülçin Aygun, our MSc student, was glowing with pride. As I happen to be a specialist on fossil hedgehogs, I examined the specimen more closely and declared solemnly that the deposits were about 10 million years old based on its stage of evolution. Being considered an expert, you learn how to bluff. Of course, only a week later, when more fossils had appeared, I turned out to be mistaken by 1 or 2 million years. But who cares, we had found what we were looking for, were able to put an age to the section we had sampled and had a nice collection for one of the Turkish students to work on. That is success. Now, can you understand why I had forgotten all about the mosquitoes?
Gülçin Aygun and Lars van den Hoek Ostende washing mud. Somewhere in there, there may be fossil rodents.