noun

An extinct cephalopod mollusc with a flat-coiled spiral shell, found commonly as a fossil in marine deposits from the Devonian to the Cretaceous periods.

In the Lower Devonian, ammonoids appeared, leaving us large limestone deposits from their shells.

adjective

Relating to the ammonoids.

This study, which represents part of my Ph.D. thesis, could not have been performed without the thorough taxonomic work carried out by many Triassic ammonoid systematists that has provided the basis for this study.