Ancyloceratidae

Ancyloceratidae Temporal range: Lower Cretaceous
Fossil of Pseudocrioceras duvalianum from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Superfamily:	†Ancyloceratoidea
Family:	†Ancyloceratidae Meek, 1876
Genera
see text

Ancyloceratidae is a family of heteromorphic ammonites that lived during the Early Cretaceous. Their shells begin as a loose spiral with whorls not touching which then turns into a straight shaft that ends in a J-shape hook or bend at end. Coarse ribbing and spines are common.

Ancyloceratidae is the type family for the Ancyloceratoidea and of the suborder Ancyloceratina. They are found in Lower Cretaceous, Upper Hauterivian to perhaps Lower Albian sediments.

Genera include:

• Acanthoptychoceras
• Ancyloceras - type genus
• Acrioceras
• Aspinoceras
• Epancyloceras
• Hoheneggericeras
• Lytocrioceras
• Megacrioceras
• Pseudocrioceras
• Rugacrioceras
• Uhligia

Ancyloceratidae are derived from the Crioceratidae, a family of Lower Cretaceous ammonites with loosely wound, open planispiral shells, probably originating from within the suborder Lytoceratina.

References

• Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.