You will all remember from Gulliver’s Travels the rival tribes of Big-Enders and Little-Enders, fiercely divided by the way in which they opened their boiled eggs.
In the fossil world we have the equivalent groups, known to us as ‘lumpers’ and ‘splitters’. In this case it’s all to do with how many species a researcher manages to identify. Let me explain.
Say you were given a pile of beautiful ammonite fossils and asked to divide them into groups. You might separate them out by size, whether the coils overlap, the curve or otherwise of the ribs and whether they divide, the presence or absence of a protruding keel, etc, etc. Now comes the tricky part. What if you were then asked how many different species you have in front of you? Bear in mind that members of a species can reproduce with each other but not with individuals from another species, something that’s impossible to check with dead animal groups.
So, are all the differences you’ve identified signs of different species – or are some just variations within a species? If you are a splitter you will say they are all different species, a lumper will declare for as few species as possible. The difference matters crucially because the presence of particular species is used as an indicator of age, environment, ancient geographical position among other things.
The most famous splitter in these parts was SS Buckman whose work on Yorkshire Type Ammonites extended to seven volumes published over a period of 21 years. It is often whispered in fossil circles that the reason for Buckman’s long-windedness was that he was paid a fee for every new species he identified. But that could be just a rumour put about by the lumpers. To split or to lump – the fight goes on!