Glochiceras
Encyclopedia
Glochiceras is a haploceratid
Haploceratidae
The Haploceratidae is one of the families to go to form the Haplocerataceae, a superfamily in the ammonitina; which according to Donovan et al can be derived from the Taramelliceratinae, a subfamily of the Oppeliidae....

 ammonite
Ammonitida
The Ammonitida is an order of more highly evolved ammonoid cephalopods from the Jurassic and Cretaceous time periods, commonly with intricate ammonitic sutures....

 characterized by a small, smooth, compressed, evolute shells with large lappets and a median lateral groove. Its geographic distribution is fairly cosmopolitan, but it is limited stratigraphically to the Oxfordian and Kimmeridgian
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....

 stages in the Upper Jurassic.

The earlier, Bajocian
Bajocian
In the geologic timescale, the Bajocian is an age or stage in the Middle Jurassic. It lasted from approximately 171.6 Ma to around 167.7 Ma . The Bajocian age succeeds the Aalenian age and precedes the Bathonian age....

, Cadomoceras
Cadomoceras
Cadomoceras is an extinct cephalopod genus from the order ammonitida that lived during the Bajocian Stage of the Middle Jurassic, approximately 178 to 175 million years ago....

is similar overall, except for having a large ventral rostrum and spatulate lappets at the aperture, and coarse ventral plications.
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