Siliceous and Delicious

Although it is late start today, owing to all the excitement over having Kati back in the house, I return to the morphospace with an unusual amount of gusto this morning. I finally have a pile of notes on the characters in those 98% of the 166 genera I’ve looked at. I’m still missing info on three genera, but I’m willing to let those go for the time being for the sake of moving on. If I find descriptions for them later on, they’ll fit in the framework I’ve got; if not, they’re not going to drastically change the answer I get.

The next phase of the morphospace project is the most exciting, because it is the most creative part—but it is also the trickiest bit. Here I need to distill my notes into a list of characters and character states that will describe all of the different morphologies I’ve seen in the 163 genera I’ve looked at.

The first challenge, which I think will be one of the more formidable ones, is how to describe the outline shape of the valve face. The idea that’s been lurking in the back of my head has been to use the number of sides of a shape as the primary character set. Thus, a circle would have a character state of 1 (a circle has 1 side), basically all of the pennate diatoms would have a character state of 2, the triangular forms would take value 3, and the few quadrangular forms would have a value of 4. Now, this gets me the basic shape, but that doesn’t in and of itself solve the problem, because there’s a wider range of valve face morphologies to cover.