''Ophiceras'' is a genus of smooth, evolute

ceratitid Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammoni ...

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

s from the Early Triassic, with a rounded venter. Fossils of the genus have been found in Armenia, Azerbaijan, China, Greenland, and India.''Ophiceras''
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Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

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Diagnosis

The shell of ''Ophiceras'' evolute, whorls all showing, slowly increasing in height, and slightly embracing the previous. Umbilicus, wide and moderately deep. Surface ornamented with faint folds, which in some develop into coarse ribs in the mature growth stage, and transverse striae. Suture is ceratitic, lobes and saddles usually long and narrow. (Smith, 1932. Arkell, 1957)

Taxonomy

''Ophiceras'' is included in the

Ophiceratidae The Ophiceratidae is a family in the ammonoidea, ammonoid order Ceratitida from the Lower Triassic, previously included in the Otocerataceae but now placed in the Noritiaceae as revised. The Ophiceratidae produced sepenticones with compressed ell ...

according to the Treatise on Invertebrate Paleontology (Arkell, 1957), but was earlier placed in the Xenodiscidae in Smith (1932). Five subgenera are recognized: ''Ophiceras (Ophiceras)'', ''O. (Acanthophiceras)'', ''O. (Discophiceras)'', ''O. (Lytophiceras)'', ''O. (Metophiceras)''. ''Ophiceras'' probably gave rise to ''

Flemingites ''Flemingites'' is a genus of evolute ammonoids from the Lower Triassic with spiral ridges on the shell. Diagnosis The shell of ''Flemingites'' is evolute so that all whorls show externally. Whorls are robust, slightly embracing, usually a lit ...

'' , which it somewhat resembles.

Diagnosis

Taxonomy

References

Further reading