Gaudryceratid

Gaudryceratid is a subfamily of ammonites, specifically belonging to the order Lytoceratida. These marine cephalopods lived during the Mesozoic Era, with their fossil record primarily found in rocks dating from the Late Cretaceous period. Gaudryceratids are characterized by their generally smooth, evolute shells, meaning the whorls of the shell are largely exposed and do not significantly overlap.

The shell aperture, or opening, of gaudryceratids is typically simple and lacks complex apertural features that are common in some other ammonite groups. Ornamentation on the shell surface, if present, is usually subtle, often consisting of fine striations or faint ribbing rather than prominent spines or tubercles. Their sutures, the lines where the internal septa meet the shell wall, are typically complex and serpentine, a common trait among Lytoceratida.

Fossils of gaudryceratids have been discovered worldwide, indicating a broad geographic distribution. They are often found in marine sedimentary deposits, particularly those formed in offshore environments. Their presence in the fossil record contributes to our understanding of ammonite evolution and the paleoecology of ancient seas. The subfamily includes several genera, such as Gaudryceras and Ageronoceras, each with distinct morphological variations within the broader gaudryceratid characteristics. Their extinction, like that of all ammonites, occurred at the Cretaceous-Paleogene boundary.