Aphelaeceras is an extinct genus from the nautilid

Nautilida

The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, Nautilus and Allonautilus, with six species...

 family Trigonoceratidae

Trigonoceratidae

The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous to the Early Permian.-Diagnosis:...

 which is part of the Trigonocerataceae

Trigonocerataceae

The Trigonocerataceae is a superfamily within the Nautilida that ranged from the Devonian to the Triassic that is thought to have contained the source for the Nautilaceae in which Nautilus is found....

, that lived during the Mississippian Period in the late Paleozoic—a nautiloid cephalopod

Aphelaeceras is evolute, compressed, with a wide umbilicus and small dorsal impression. Whorl section is subrectangular with convex sides that slope toward a concave venter. Ventral shoulder are subangular, umbilical shoulders broadly rounded. The suture has a narrow ventral lobe and broad lateral lobes. The siphuncle is barely ventral from the center.

Aphelaeceras has been found in Mississippian (L. Carb) strata in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. The genus was named by Hyatt, 1844. The type, A. difficile (DeKoninck) came from Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

.

Mesochasmoceras, from the Lower Carb of Europe is similar in having a concave venter but early whorls are nearly ovate in cross section and the umbilicus has a wide perforation.

References

• Kummel, B, 1964; Nautiloidea- Nautilida; Treatise on Invertebrate Paleontology Part K Nautiloidea; Geological Society of America and University of Kansas Press.
• Flower, R.H and Kummel, B. 1950; A Classification of the Naulioidea; Journal of Paleontology, V 24, no 5. pp604–616, Sept 1950