Describing Ammonoid Conchs

Research always requires the use of a common language and particularly of common technical terms. Thus, the definition of terms is fundamental for any scientific work, and this includes also the definition of species. In this chapter, we do not discuss species concepts but provide a guideline on how to describe ammonoids in a manner that is intelligible to the majority of the fellow cephalopod-workers. Accordingly, we list the most important terms and describe how to quantify and how to properly use them. We stress that the inclusion of morphological details throughout ontogeny as well as information on intraspecific variability can be important. This is essential, because species are the classical unit used in biodiversity and evolutionary studies and hence, a more or less uniform handling of this issue is desirable.