Euomphalus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of fossil marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropods

Gastropoda

The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...

 known to have lived from the Silurian

Silurian

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...

 to the Middle Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

.

Euomphalus is characterized by a closely coiled shell with a depressed to slightly elevated spire and a channel-bearing angulation on the upper surface of the whorls. The lower surface of the whorls is rounded to angular.

Amphiscapha

Amphiscapha

Amphiscapha is a genus of marine mollusks that may be fossil sea snails. It is an euomphalid genus which is found in the Pennsylvanian and Lower Permian of North America and South America.-Description:...

, Philoxene, and Straparollus are among similar related genera. Serpulospira, also related, differs in having a broadly open spiral in the adult form.

Taxonomy

Euomphalus is the type genus

Type genus

In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

 of the family Euomphalidae

Euomphalidae

Euomphalidae is an extinct family of Paleozoic molluscs which may possibly be gastropods with anisostrophically coiled shells .- Genera :Genera in the family Euomphalidae include:...

. Euomphalus pentangulatus (Sowerby) is its type species.