Phenotypic plasticity of Acanthoscaphites tridens (Late Cretaceous ammonites): additional data

The concept of phenotypic plasticity of the temporal species Acanthoscaphites tridens s. str., as recently proposed by myself is elaborated upon, in response to issues raised in a commentary to the original paper. The terms phenomorphic class and dominant phenotype are explained in greater detail, as well as the evaluation of phenotypic plasticity in studies for extinct species. (C) 2010 Elsevier Ltd. All rights reserved.