On taxonomy

Taxonomy first of all has to do with organizing things and ideas into a hierachy of logical sets. Not only should it be based on real, natural relations, i.e. have evolutionary validity, but should provide a basis for conversation. Ammonoids may have been derived from one group of nautiloids (orthocerids) but when we refer to nautiloids it should be implicit we aren't including ammonoids, nor is there any reason to do so.

I prefer the nested Linnean taxonomic approach to the less precise cladistic approach, although the latter does have application in phylogenetics. Regarding cephalopod taxonomy I generally follow the schemes of Rousseau Floower and the Treatise on Invertebrate Paleonotolgy (parts K, Nautiloidea etc, and L, Ammonoidea) with some ideas of my own.

Ammonites vs Nautiloids coming up.