Cathodoluminescence and microprobe analysis in monopleurid shells from Aptian – Lower Albian limestones
in Ereño (Bizkaia) has allowed to us to realize that different rudist shells show different diagenetic responses
in front of a similar degree of diagenetic alteration. Monopleurid shells show a relatively high diagenetic
degree when compared to that of requienids. Early neomorphism processes were dissimilar for different
shells. The relatively thin monopleurid prisms could allow a diagenetic alteration in a higher degree than
that affected requienid shells