Wednesday, September 8, 2010

Anagenesis on the pterosaur line

Here is a standard cladogram.

This shows pterosaurs as a diverging line.
Let's consider that line in a bit more detail.
First let's review the general idea about what happens on a line (whether it be diverging or not).
Anagenesis is what happens on lines. (Which is perfectly reasonable).
Remember this cladogram?

Notice the short red horizontal lines. Each represents an event/process of anagenesis.
Notice that such lines appear on the diverging lines.

Putting these ideas together we can see that there were such anagenetic events/process on the pterosaur line. And we know that is the case, because there are the Rhamphorhynchoidea and the Pterodactyloidea (the pterodactyls). The pterodactyls developed as a result of anagenesis.
I will continue this in the next post.

1 comment:

  1. That's not really anagenesis, when dealing with fossil taxa, you generally assume that these taxa share a common ancestor, not that one is descended from the other, also, rhamphorhychoidea is paraphyletic, and if it were redefined to include pterodactyloidea, it would be synonymous with pterosauria. Also, how does this support your theory? Saying that cladistic analyses ignore anagenesis support or detract from your theory in any way. What is your point?