Ammonite genera refer to the taxonomic groupings of extinct marine mollusks belonging to the subclass Ammonoidea. These organisms thrived in ancient seas from the Devonian period (approximately 400 million years ago) until their extinction at the end of the Cretaceous period, about 66 million years ago. Ammonites are characterized by their coiled, chambered shells, often exhibiting intricate suture patterns.
Numerous genera have been described based on morphological features such as shell geometry, ribbing, and suture complexity. Examples of well-documented ammonite genera include Ammonitites, Acanthoceras, Placenticeras, Hoploscaphites, and Diplomoceras. Classification is primarily based on fossil remains, with over 800 genera recognized in the paleontological literature.
A "List of ammonite genera" would typically serve as a taxonomic catalog, often compiled in paleontological databases, scientific publications, or reference works such as the Treatise on Invertebrate Paleontology. Such lists aim to provide systematic overviews, including valid names, synonyms, stratigraphic ranges, and geographic distributions.
No indication of irregularity or non-recognition is found with the term "List of ammonite genera"; it represents a standard aggregative concept in paleontology and is supported by extensive scholarly sources.