Gaudryceratidae

Gaudryceratidae is a family of extinct ammonites, a diverse group of cephalopods that lived in the oceans during the Mesozoic Era. These ammonites are characterized by their generally evolute or semi-evolute shells, meaning the whorls of the shell are widely separated or only moderately overlapping. A common feature is the presence of smooth, rounded ribs, or sometimes the shell can be nearly smooth. The umbilicus, the central opening of the shell, is typically wide and deep. The aperture, the opening from which the ammonite emerged, is usually simple and lacks elaborate flares or constrictions, though it can be slightly constricted in some species. Gaudryceratid ammonites are known for their often intricate suture patterns, which are the lines where the septa (internal walls dividing the shell chambers) meet the outer shell wall. These sutures can be complex, with numerous lobes and saddles, and are important for taxonomic classification. The family is distributed globally, with fossils found in marine deposits from the Cretaceous period. They are considered important index fossils for dating rock strata from this time. Notable genera within Gaudryceratidae include Gaudryceras, Mesogaudryceras, and Triceras. The exact diet and lifestyle of gaudryceratids are inferred from their morphology and their fossilized environment, suggesting they were likely nektonic predators or scavengers.