Ancyloceratidae
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 Temporal range: Lower Cretaceous | |
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| 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 |
| Suborder: | †Ancyloceratina |
| Superfamily: | †Ancyloceratoidea |
| Family: | †Ancyloceratidae Meek, 1876 |
| Genera | |
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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
- Antarcticoceras[1]
- 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
- M.R.A. Thomson, « Ammonite faunas of the Lower Cretaceous of south-eastern Alexander Island », British Antarctic Survey Scientific Reports, No. 80 (1974), p.1-44.
- 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.
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