Binomial Nomenclature

Binomial nomenclature names each species with a two-part Latinized name, the genus followed by the specific epithet, as standardized by Linnaeus.

Definition

Binomial nomenclature is the convention of naming a species by a binomen consisting of a capitalized genus name and a lowercase specific epithet, both Latinized and conventionally italicized.

Scope

This topic covers the structure and formatting of two-part species names, the conventions of capitalization, italics, and authorship citation, the treatment of subspecific names, and the rationale for a uniform binomial system across biology.

Core questions

• What are the two parts of a scientific species name and how are they formatted?
• How is authorship and date attached to a name?
• How are subspecies and other infraspecific ranks named?
• Why did a uniform binomial system displace earlier polynomial descriptions?

Key theories

Two-part naming

A species name combines a genus name shared with close relatives and a unique specific epithet, giving every species a concise, globally consistent label.

Authorship and stability

Citing the author and date of a name links it to its original description and type, supporting unambiguous interpretation under the codes.

Clinical relevance

Consistent binomials let clinicians, regulators, and researchers refer to pathogens, vectors, and biological resources without ambiguity, which is essential for diagnosis, trade, and the literature record.

History

Linnaeus consistently applied two-word names in his mid-eighteenth-century works, replacing long descriptive polynomials; the system was later formalized and made mandatory by the international nomenclatural codes.

Key figures

• Carl Linnaeus

Seminal works

• iczn1999
• winston1999

Frequently asked questions

Why is the genus capitalized but not the species epithet?

By convention under the codes, the genus name is capitalized and the specific epithet is lowercase, with the whole binomial italicized, so names are formatted consistently worldwide.

What does the name after a species, such as 'L.', mean?

It is the authorship citation indicating who first validly published the name, with 'L.' being the standard abbreviation for Linnaeus.