Stephanoceras (Normannites) sp. (Munier-Chalmas 1892)

Lovely specimen, and great prep as usual, Roger - well done. Interesting, so is Normannites classified as a subgenus of Stephanoceras? I'd of thought, if it's certain that they're microconch and macroconch, that they'd both be classified under the same genus name (and there would be no need for a subgenus).

The M's and m's are a subject in themselves. Most of them have different genus names since many were given their names before proper research began on the subject and the rules of nomenclature prohibit changing them now. It's still not clear in a good number of cases what belongs to what. At least these ones are run under the same Genus.

Thanks Roger. Which nomenclature rules do you refer to?

In this case I'm talking about the first author, but here's some general information:

http://www.geol.lsu.edu/hart/NOTES/taxonomy.htm

http://en.wikipedia.org/wiki/International_Code_of_Zoological_Nomenclature