• The common name "robin" in the United States is used for a thrush, Turdus migratorius, or the American Robin.

  • european robin

    "Robin" in Europe is a completely different species, Erithacus rubecula.

  • Drawing of Carl Linnaeus

    Carl von Linné created binomial nomenclature in the 18th century so each living thing would have an agreed upon scientific name.

  • gigantic bug

    The Titan beetle, Titanus giganteus. Its scientific name refers to its size.

  • Male Iandumoema smeagol

    Landumoema smeagol, a spider named after Smeagol from the Lord of the Rings saga.


Every species known to science has a name, referred to as a scientific name or binomen. For example, Homo sapiens is the scientific name for humans. There are two main functions of these Latin names: to identify a species and indicate its evolutionary relationships with other organisms. The first half is the genus name that links an organism to its closest relatives, while the second species name implies their uniqueness.

Why do we use Latin names in addition to common names? Species may have several common names, but only one scientific name, or different species may have the same common name. For example, the "robin" in the United States is a thrush Turdus migratorius, while the "robin" in Europe is a completely different species, Erithacus rubecula. Scientific names are not likely to be confused for something else, as there are strict guidelines for naming species. To name a species, a scientist must describe a holotype, which is a specimen used as the basis for the morphology of the species, and follow international codes such as the International Code of Nomenclature for Algae, Fungi and Plants

Species names are one part of the business of biological taxonomy. Individual genera are also grouped into larger groups in a hierarchy. For example, Homo sapiens is in the "Order Primates," the "Class Mammalia" within the "Kingdom Animalia." These groups reflect the evolutionary relationships of the species. While taxonomy acts as a concrete reference system to the natural world, it is also constantly changing as our scientific understanding grows.

Latin or Binomial Nomenclature

Binomial nomenclature, the system used to assign species with their two-part Latin names, originated in the 18th century. Carl von Linné (1707 – 1778), the naming system’s mastermind, established a system of tiered taxonomic classification, which assigned species formal names, all outlined in his book, Systema Naturae. This way, all living things would not be confused with multiple common names, but have an agreed upon scientific name. The names were formulated from Latin words; Linné even latinized his own name, to the name most people know him as today: Carolus Linnaeus.

Choosing a Name

Giving an organism a name is no small process, and involves following a specific set of rules that governs how organisms are classified. Different types of organisms have their own codes of nomenclature but all generally abide by the following principles:

Principle of Binominal Nomenclature: The scientific name of a species, and not of a taxon at any other rank, is a combination of the genus and species; the use of a trinomen for the name of a subspecies and of uninominal names for taxa above the species group is also accepted.

Principle of Coordination: Within the family group, genus group or species group a name established for a taxon at any rank in the group is deemed to be simultaneously established with the same author and date for taxa based on the same name-bearing type at other ranks in the group.

Principle of the First Reviser: The First Reviser determines the relative precedence of two or more names or nomenclatural acts published on the same date, or of different original spellings of the same name.

Principle of Homonymy: The name of each taxon must be unique. Consequently a name that is a homonym of another preexisting name must not be used as a valid name.

Principle of Priority: The valid name of a taxon is the oldest available name applied to it (starting at 1756), provided that the name is not invalidated by any provision of a Code or by any ruling by a Commission.

Principle of Typification: Each nominal taxon in the family, genus or species group has a name-bearing type specimen (holotype) fixed to act as a reference for the species.

Naming Species in a Modern Age

Scientists are constantly finding new species and having to name them. In most instances the new scientific name reflects an attribute of the organism such as its morphology (e.g., the Titan beetle, Titanus giganteus), habitat (e.g., the human head and body louse, Pediculus humanus), or geographical distribution (e.g., the Californian Lady Slipper,Cypripedium californicum). Organisms are often named in honor of scientists – there are more than 300 taxa named after Charles Darwin, and many named after Linnaeus. Names can also be inspired by mythology such as the extinct elephant Stegodon ganesa; the Hindu god Ganesa is usually depicted with the head of an elephant.

Given that there are so many species already named, and each name must be unique, scientists have become creative! Pop culture references are now quite commonplace in taxonomy e.g., the polychaete worm Bushiella beatlesi, referring to the "The Beetles", a popular band in the 1960's. In 2015, a new species of daddy longlegs, Iandumoema smeagol, was found in Brazil. This species of arachnid is a cave dwelling creature, which in both appearance and behavior resembles Smeagol (later Gollum) in the Lord of the Rings saga. In Central and North America, a genus of fungus beetles goes by a very peculiar name - “Gelae” (yes, pronounced like jelly). The members of this group all make their homes in different kinds of fungus, but their names are much more appetizing. They include Gelae baen, Gelae belae, Gelae rol, and Gelae donut.

What is a Type Specimen?

The Dimetrodon milleri specimen at the Harvard Museum of Natural History. Credit: © President and Fellows of Harvard College.

When Harvard paleontologist Alfred Romer discovered Dimetrodon milleri in 1937, he discovered the first of the species, and one of the most complete Dimetrodon specimens to date. It became the “type specimen”, a true example of the species, and one that scientists use to identify specimens of the same species. A type can be a specimen, a culture, an illustration, or a bacterial code, depending on the type of organism. All scientifically named species on Earth, both living and extinct, have their own type specimen, which contains the defining characteristics of the species. They are usually housed in natural history collections.


Since Harvard’s Dimetrodon milleri is the specimen for which the species is named, it is known as the name-bearing holotype. But there are other “types” as well. “Paratypes” are other specimens of the same species collected at the same time as the holotype. “Allotypes” are the member of the opposite sex of the holotype, usually collected at the same time. “Neotypes” are specimens that assume the holotype’s role should the original specimen be lost or destroyed.

Reflecting Evolution

Linnaeus set up his biological classification system one hundred years before Darwin’s publication of his theory of evolution by natural selection. Today scientific naming also intends to reflect evolutionary relationships and so names change. Scientists continue to investigate those relationships. In particular, the increased availability of genomic and other molecular data has changed our understanding of those phylogenies, which leads to new names. For example, recent studies of the DNA of giraffe populations have shown that there is significant genetic variation between different populations, suggesting each one is genetically isolated. Instead of one species of giraffe, Giraffa camelopardalis there are four: Giraffa camelopardalis, Giraffa reticulata, Giraffa tippelskirchi, and Giraffa giraffa. Similarly some scientists argue that there are three genera of pangolins (Manis, Phataginus, and Smutsia) rather than one (Manis).
Giraffa camelopardalis. Credit: Hans Hillewaert.CC BY-SA


Taxon: A population, or group of populations of organisms, whether or not names, which are usually inferred to be phylogenetically related and which have characters in common which differentiate

Taxonomy: The theory and practice of classifying organisms

Taxonomic classification: A hierarchy of names that identify organisms down to the species level. The order is as follows: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Binomen: Also known as the scientific name of a species, is a combination of two names the genus and species. The generic name must begin with an upper-case letter and the specific name must begin with a lowercase letter

Trinomen: The scientific name of a subspecies is a combination of three names, the binomen plus the subspecies name

Common name: A colloquial name for a species or taxon that is often different from the scientific name (except: Boa constrictor)

Holotype: A single specimen that is used to describe and name a species

Phylogenetic: The study of evolutionary relationships between groups of organisms

Zoological nomenclature: The system of scientific names applied to taxonomic units of extant or extinct animals

Slideshow Image Credits 
American Robin,Turdus migratorius by Dori, Wikimedia Commons.CC BY-SA; European Robin, Erithacus rubecula by Andreas Trepte, Wikimedia Commons. CC BY-SA; A painting of Carolus Linnaeus by Alexander Roslin, 1774. Public Domain; Titan beetle, Titanus giganteus by Bernad Dupont, Flickr: EOL Images. CC BY-NC-SA; Iandumoema smeagol by Ricardo Pinto-da-Rocha, Rafael Fonseca-Ferreira, and Maria Elina Bichuette, Zookeys. CC BY 4.0