illinoiensis

Illinoiensis is a Latinized species epithet used in the scientific names of organisms to indicate a connection with the U.S. state of Illinois. The form is derived from the proper noun Illinois, with the Latin suffix -ensis meaning “originating from” or “inhabited by” — a common pattern for place-based epithets in taxonomic naming.

In zoological and botanical nomenclature, illinoiensis can denote that the species was first described from Illinois, was commonly found there, or is otherwise associated with the region. It is one of many toponymic epithets used to memorialize geography rather than anatomy.

Spelling and usage: The epithet may appear in several variant spellings in the literature, notably illinoiensis and illinoensis. The precise spelling is determined by the author of the original description and is treated as the official name in taxonomic databases and catalogs.

Because epithets refer to localities, they do not always reflect current distribution, and some species named illinoiensis may be found far outside Illinois.

The epithet illinoiensis is most common in North American taxa and reflects historical naming conventions; it serves as a geographic marker rather than a statement about biology.