Ancyloceras is an extinct genus of heteromorph ammonites found throughout the world during the Lower Cretaceous, from the Lower Barremian epoch until the genus extinction during the Lower Aptian.[1][2][3]
| Ancyloceras | |
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | †Ammonoidea |
| Order: | †Ammonitida |
| Suborder: | †Ancyloceratina |
| Family: | †Ancyloceratidae |
| Genus: | †Ancyloceras d'Orbigny, 1842 |
| Species | |
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See text | |
Selected species
edit- Ancyloceras audouli Astier, 1851
- Ancyloceras fallauxi Uhlig, 1883
- Ancyloceras mantelli Casey, 1960
- Ancyloceras matheronianum d'Orbigny, 1842
- Ancyloceras vandenheckii Astier, 1851[1]
Description
editAncyloceras ammonites have a shell reaching a length of about 10 centimetres (3.9 in) and a width of about 7 centimetres (2.8 in). They are known as heteromorph shaped, with a partly uncoiled shell and the aperture directed toward the coiled part.
Most ammonites are homomorph, as they maintain the same shape throughout the growth, while the ammonites in this genus have uncoiled shells (heteromorph or different-shaped ammonites), that would have precluded fast swimming.[1]
Distribution
editFossils of Ancyloceras species are found in the Cretaceous Barremian Stage (117-113 million year old) marine strata of Europe, Colombia and Morocco.
References
edit- ^ a b c "Ancyloceras". Paleobiology Database.
- ^ Sepkoski, Jack Sepkoski's Online Genus Database – Cephalopoda
- ^ Fossil Museum
External links
edit- Clark, David L. (November 1958). "Anisoceras and Ancyloceras from the Texas Cretaceous". Journal of Paleontology. 32 (6): 1076–1081. JSTOR 1300773.
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