Zoïs

Zoïs is a genus of extinct ammonites, a diverse group of marine mollusks that lived from the Devonian to the end of the Cretaceous period. Ammonites are characterized by their coiled, chambered shells, which are often preserved as fossils. The genus Zoïs belongs to the order Ceratitida, a group of ammonites that flourished during the Triassic period.

Fossils attributed to Zoïs have been found in various parts of the world, particularly in Europe. These ammonites are typically small to medium-sized, with shells that exhibit a distinctive morphology. The coiling of the shell in Zoïs is generally evolute, meaning that the earlier whorls are largely exposed. Ornamentation on the shell surface can vary but often includes ribs and tubercles. The sutures, which are the lines where the septa meet the shell wall, are typically ceratitid in type, meaning they are complex with external lobe elements that are frilled.

The paleoecological role of Zoïs is inferred from its fossil occurrences. As marine organisms, they would have inhabited ancient seas, likely in relatively shallow environments. Like other ammonites, they were cephalopods and are presumed to have been nektonic predators, swimming in the water column and feeding on smaller marine life. The extinction of the ammonites, including the genus Zoïs, occurred at the end of the Cretaceous period, coinciding with the K-Pg extinction event. The study of Zoïs contributes to our understanding of ammonite evolution, diversity, and the ancient marine ecosystems they inhabited.