''Helcionella'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of helcionellid, a

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

marine

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

animal that is considered to be a

mollusk Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...

and may possibly be a gastropod. The shells of these animals are about a centimetre in size. The tip of the shell extends beyond the rear extremity of the shell's aperture, and the shell is "endogastric" in shape. ''Helcionella'' is the

type genus In biological taxonomy, the type genus is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearing type of a nominal ...

of the family Helcionellidae.

References

* A. W. Grabau and H. W. Shimer. 1909. North American index fossils, invertebrates 1-909 Helcionelloida Cambrian animals of Europe Paleozoic life of Alberta Paleozoic life of British Columbia Paleozoic life of Newfoundland and Labrador {{paleo-mollusc-stub Cambrian genus extinctions