''Arietites'' is a genus of massive, giant evolute, psiloceratacean

ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

in the family

Arietitidae Arietitidae is a family of true ammonites that make up part of the superfamily Psiloceratoidea, named after the type genus '' Arietites''. They comprise medium-size to large or gigantic genera which in general are strongly ribbed, tuberculate in ...

in which

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). In nature File:Photograph and axial plane floral diagram ...

are subquadrate and transversely ribbed and low keels in triplicate, separated by a pair of longitudinal grooves, run along the

venter Venter or Venters is an Afrikaans (and rarely, Jewish) surname, and may refer to: Venter * AJ Venter (b. 1973), South African rugby union footballer * Al J Venter (b. 1938), author * André Venter (b. 1970), South African rugby union footballer * ...

. Fossils are known world wide from the lower

Sinemurian In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annu ...

stage of the

Lower Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma&nb ...

. Safari Ltd made an ''Arietites bucklandi'' figurine in 2014. Similar

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

include '' Megarietites'' in which the keels are reduced and '' Epammonites'' in which the ribs are more closely spaced.

Species

* '' Arietites ablongaris'' * '' Arietites alcinoe'' Reynès, 1879 * '' Arietites anastreptoptychus'' Franz Wähner, 1891 (possibly a synonym of '' Paracaloceras subsalinarium''; Wähner) * '' Arietites bisulcatus'' * '' Arietites bonnardii'' Alcide Dessalines d'Orbigny, 1879 * '' Arietites brookei'' * '' Arietites bucklandi'' George Brettingham Sowerby, 1816 * '' Arietites crossi'' * '' Arietites gaudryi'' Reynès * '' Arietites geometricus'' Albert Oppe, 1856 * '' Arietites hettangiensis'' * '' Arietites isis'' * '' Arietites longicellus'' Friedrich August Quenstedt, 1858 * '' Arietites meigeni'', (possibly a synonym of '' Leptechioceras meigeni'') * '' Arietites meridionalis'' Reynès * '' Arietites obesulus'' J. F. Blake, 1876 * '' Arietites obtusus'' * '' Arietites pinguis'' * '' Arietites planaries'' Reynès, 1879 * '' Arietites quadratus'' E. Donovan, 1952 * '' Arietites radiatus'' C. T. Simpson, 1843 * '' Arietites retroversicostatus'' Canavari * '' Arietites rotiformis'' Sowerby * '' Arietites scunthorpense'' * '' Arietites semicostatus'' A. T. Young & Bird, 1828 * '' Arietites spiratissimus'' * '' Arietites subsalinarius'' Wähner, 1891, (possibly a synonym of '' Paracaloceras subsalinarium''; Wähner) * '' Arietites tenellus'' C. T. Simpson, 1855 * '' Arietites turneri'' * '' Arieties westfalicus'' Lange (possibly a synonym of '' Coroniceras westfalicum'' Lange, 1925) * '' Arietites wichmanni'' August Rothpletz, 1892 Note:'' Arietites ''now only represents a purely morphological term. A revision of the genus is still pending, its representatives are therefore initially classified as'' Coroniceras (Arietites)'' under'' Coroniceras ''.

Species

References

Further reading