Introduction
Intraspecific variation of conch shape has been documented for many
Mesozoic ammonoids (e.g., Aguirre-Urreta, 1998; Bhaumik et al., 1993;
Dagys and Weitschat,1993a, b; Mitta, 1990; Tanabe, 1993), while
Paleozoic ammonoids are commonly regarded as expressing much less
variability. Traditionally, species concepts which were applied on
Devonian ammonoids were strictly typological and based on the
holotype and few paratypes.  The investigation of larger populations
was only rarely achieved (cf.  Dzik, 1985 for Mesozoic ammonoids).  
However, it is urgently required to apply new methods such as
population studies for a better understanding of phylogenetic
relationships, intraspecific variability, and spatial biodiversity.