In biology, trinomial nomenclature is the system of names for
taxa
In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...
below the
rank of
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
. These names have three parts. The usage is different in
zoology
Zoology ( , ) is the scientific study of animals. Its studies include the anatomy, structure, embryology, Biological classification, classification, Ethology, habits, and distribution of all animals, both living and extinction, extinct, and ...
and
botany
Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...
.
In zoology
In
zoological nomenclature
The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its formal author, t ...
, a trinomen (), trinominal name, or ternary name is the name of a
subspecies
In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...
.
A trinomen is a name with three parts:
generic name,
specific name and
subspecific name. The first two parts alone form the
binomen
In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...
or
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
name. All three names are typeset in italics, and only the first letter of the generic name is capitalised. No indicator of rank is included: in
zoology
Zoology ( , ) is the scientific study of animals. Its studies include the anatomy, structure, embryology, Biological classification, classification, Ethology, habits, and distribution of all animals, both living and extinction, extinct, and ...
, subspecies is the only rank below that of species.
For example: "''Buteo jamaicensis borealis'' is one of the subspecies of the
red-tailed hawk
The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members of ...
(''Buteo jamaicensis'')."
Examples include ''Gorilla gorilla gorilla'' (
Savage and
Wyman, 1847) for the
western lowland gorilla
The western lowland gorilla (''Gorilla gorilla gorilla'') is one of two Critically Endangered subspecies of the western gorilla (''Gorilla gorilla'') that lives in Montane ecosystems#Montane forests, montane, Old-growth forest, primary and sec ...
and ''Gorilla gorilla diehli'' (
Matschie, 1903) for the
Cross River gorilla (which are subspecies of ''Gorilla gorilla'', the
western gorilla
The western gorilla (''Gorilla gorilla'') is a great ape found in Africa, one of two species of the hominid genus ''Gorilla''. Large and robust with males weighing around , the species is found in a region of midwest Africa, geographically iso ...
); ''Bison bison bison'' (
Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
, 1758) for the
plains bison
The plains bison (''Bison bison bison'') is one of two subspecies/ecotypes of the American bison, the other being the wood bison (''B. b. athabascae''). A natural population of plains bison survives in Yellowstone National Park (the Yellowstone P ...
and ''Bison bison athabascae'' (Rhoads, 1898) for the
wood bison
The wood bison (''Bison bison athabascae'') or mountain bison (often called the wood buffalo or mountain buffalo), and Athabaskan bison (or Athabaskan buffalo), is a distinct northern subspecies or ecotype of the American bison. Its original ran ...
(which are subspecies of ''Bison bison'', the
American bison
The American bison (''Bison bison''; : ''bison''), commonly known as the American buffalo, or simply buffalo (not to be confused with Bubalina, true buffalo), is a species of bison that is endemic species, endemic (or native) to North America. ...
).
In a
taxonomic publication, a name is incomplete without an author citation and publication details. This indicates who published the name, in what publication, and the date of the publication. For example: "''Phalacrocorax carbo novaehollandiae'' (Stephens, 1826)" denotes a subspecies of the
great cormorant (''Phalacrocorax carbo'') introduced by
James Francis Stephens
James Francis Stephens (16 September 1792 – 22 December 1852) was an England, English entomologist and naturalist. He is known for his 12 volume ''Illustrations of British Entomology'' (1846) and the ''Manual of British Beetles'' (1839).
...
in 1826 under the subspecies name ''novaehollandiae'' ("of
New Holland").
If the generic and specific name have already been mentioned in the same paragraph, they are often abbreviated to initial letters. For example, one might write: "The great cormorant ''Phalacrocorax carbo'' has a distinct subspecies in
Australasia
Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...
, the black shag ''P. c. novaehollandiae''".
While binomial nomenclature came into being and immediately gained widespread acceptance in the mid-18th century, it was not until the early 20th century that the current unified standard of nomenclature was agreed upon. This became the standard mainly because of tireless promotion by
Elliott Coues
Elliott Ladd Coues (; September 9, 1842 – December 25, 1899) was an American army surgeon, historian, ornithologist, and author. He led surveys of the Arizona Territory, and later as secretary of the United States Geological and Geographi ...
– even though trinomina in the modern usage were pioneered in 1828 by
Carl Friedrich Bruch and around 1850 were widely used especially by
Hermann Schlegel
Hermann Schlegel (10 June 1804 – 17 January 1884) was a German ornithologist, herpetologist and ichthyologist.
Early life and education
Schlegel was born at Altenburg, the son of a brassfounder. His father collected butterflies, which stimulated ...
and
John Cassin
John Cassin (September 6, 1813 – January 10, 1869) was an American ornithology, ornithologist from Pennsylvania. He worked as curator and vice president at the Philadelphia Academy of Natural Sciences and focused on the systemic classification ...
. As late as the 1930s, the use of trinomina was not fully established in all fields of zoology. Thus, when referring especially European works of the preceding era, the nomenclature used is usually not in accord with contemporary standards.
In botany
For algae, fungi, plants, and their fossils, there is an indeterminate number of infraspecific ranks allowed below the level of species. The secondary ranks below the species rank are
variety and
forma, and more ranks can be made by using the prefix "sub" to make subspecies, subvariety, subforma. Very rarely even more forms are created, such as supersubspecies. Not all of these ranks need to be specified, for example, some authors prefer to divide plant species into subspecies, while others prefer to use varieties.
These ranks are components of a
biological classification
In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon), and these groups are give ...
, for example ''
Corylopsis sinensis'' var. ''calvescens'' f. ''veitchiana'' is an ornamental garden plant. However, a
name
A name is a term used for identification by an external observer. They can identify a class or category of things, or a single thing, either uniquely, or within a given context. The entity identified by a name is called its referent. A person ...
is not the same as a classification, and the name of this plant is a trinomial with only three parts,
[ article 24.1] the two parts of the species name ''Corylopsis sinensis'', plus the forma epithet ''veitchiana'', to give ''Corylopsis sinensis'' f. ''veitchiana''.
See also
*
Binomial nomenclature
In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...
*
Nomenclature
Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. (The theoretical field studying nomenclature is sometimes referred to as ''onymology'' or ''taxonymy'' ). The principl ...
References
{{DEFAULTSORT:Trinomial Nomenclature
Biological nomenclature