Wednesday, March 30, 2011

Why "Nemagraptus gracilis"?


Hello all,
I'm David Bapst, a graduate student at the University of Chicago. I'm starting this blog to answer some questions my friends have about paleontology. I'll probably also bring up more advanced topics in phylogenetic comparative methods and functional morphology, as they relate to paleobiology and topics connected to graptolite studies. Finally, I may occassionally use this to discuss a matter involving independent roleplaying game design, which is a minor hobby of mine (my main hobby being my work).

But you might ask: why name my blog after a graptolite species?

First of all, Nemagraptus gracilis is the most beautiful graptolite, in my opinion. I've made a nice little figure of it, to the right, which I've also made the background. You've gotta admit, it's a nice little shape.

Second of all, Nemagraptus represents much of what is interesting about graptoloid morphology and function. Nemagraptus regains a multi-branched form, having evolved from two-branched Dicellograptus-like ancestors, but does so via a novel constructional modification ('cladia'). Nemagraptus's form makes it instantly recognizable, which is probably also why it is a major index fossil. There may also be some Cyrtograptus species in the Silurian which converge on a Nemagraptus form (Mitchell, 1990). Work by Fortey and Bell (1987) also suggested that is form would be optimal for feeding efficiency. Its spiral form has also been of interest to those curious about graptoloid hydrodynamics (Rigby and Rickards, 1989). These connections to functional research make it a good emblem for my research into graptoloid function.

Note that Nemagraptus is also relatively well-understood in terms of its phylogenetic relationship. This is another key connection to my researching involving the phylogeny of graptoloids. Note that I also picked a branching graptolite: just like a phylogenetic tree.
-Dave