Taxonomic interpretation and sexual dimorphism in the Early Cretaceous (Valanginian) ammonite Valanginites nucleus (ROEMER, 1841)

Sexual dimorphism in the Valanginian ammonite Valanginites nucleus (ROEMER, 1841), is recognised in the material from Wąwał, Central Poland. Two sexes, differing in size and number of ribs are distinguished. Intraspecific ornament variation is linked to sexual dimorphism. Three morphotypes (nucleus, wilfridi and ventrotuberculatum) occur along with forms intermediate between these morphotypes. In all the morphotypes two sexes were found. Valanginites bachelardi is interpreted as the microconch of the nucleus morphotype.