Taxonomic rank
Encyclopedia
In biological classification
, rank is the level (the relative position) in a taxonomic
hierarchy
. Examples of taxonomic ranks are species
, genus
, family
, and class
. Each rank subsumes under it a number of less general categories. The rank of species, and specification of the genus to which the species belongs is basic, which means that it may not be necessary to specify ranks other than these. The International Code of Zoological Nomenclature
defines rank as:
In his landmark publications, such as the Systema Naturae
, Carolus Linnaeus
used a ranking scale limited to: kingdom, class, order, genus, species, and one rank below species. Today, nomenclature is regulated by the nomenclature codes
, which allow names divided into an indefinite number of ranks. There are seven main taxonomic ranks: kingdom, phylum or division, class, order, family, genus, species. In addition, the domain (proposed by Carl Woese
) is now widely used as one of the fundamental ranks, although it is not mentioned in any of the nomenclature codes.
A taxon is usually assigned a rank when it is given its formal name. The basic rank is that of species. The next most important rank is that of genus: when an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. The third-most important rank, although it was not used by Linnaeus, is that of family.
The species name is sometimes called a binomial
, that is, a two-term name. For example, the zoological name for the human species is Homo sapiens: this is usually italicized in print (and underlined when italics are not available). In this case, Homo is the generic name and refers to the genus; it is capitalized; sapiens indicates the species: it is not capitalized.
: superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.
The International Code of Zoological Nomenclature divides names into "family-group names", "genus-group names" and "species-group names". The Code explicitly mentions:
----
Family
----
Genus
----
Species
----
The rules in the Code apply to the ranks of superfamily to subspecies, and only to some extent to those above the rank of superfamily. In the "genus group" and "species group" no further ranks are allowed. Among zoologists, additional terms such as species group, species subgroup, species complex and superspecies are sometimes used for convenience as extra, but unofficial, ranks between the subgenus and species levels in taxa with many species (e.g., the genus Drosophila
).
At higher ranks (family and above) a lower level may be denoted by adding the prefix "infra", meaning lower, to the rank. For example infraorder (below suborder) or infrafamily (below subfamily).
There are definitions of the following taxonomic ranks in International Code of Nomenclature for Cultivated Plants
: cultivar group, cultivar.
According to Art 3.1 of the ICBN the most important ranks of taxa are: kingdom, division or phylum, class, order, family, genus, and species. According to Art 4.1 the secondary ranks of taxa are tribe, section, series, variety and form. There is an indeterminate number of ranks. The ICBN explicitly mentions:
----
primary ranks
----
kingdom (regnum)
division or phylum (divisio, phylum)
class (classis)
order (ordo)
----
family (familia)
genus (genus)
species (species)
----
The rules in the ICBN apply primarily to the ranks of family and below, and only to some extent to those above the rank of family. Also see descriptive botanical names
.
only names of genera, species and varieties are still used.
Taxa at the rank of genus and above get a botanical name
in one part (unitary name); those at the rank of species and above (but below genus) get a botanical name in two parts (binary name); all taxa below the rank of species get a botanical name in three parts (an infraspecific name
).
For hybrids getting a hybrid name
, the same ranks apply, preceded by "notho", with nothogenus as the highest permitted rank. (The hybrid's nothotaxon is an alias for a list of all of the taxa which are ancestral to the hybrid.)
so familiar in genetics laboratories (Drosophila melanogaster), human
s (Homo sapiens), the pea
s used by Gregor Mendel
in his discovery of genetics
(Pisum sativum), the "fly agaric" mushroom Amanita muscaria
, and the bacterium Escherichia coli
. The eight major ranks are given in bold; a selection of minor ranks are given as well.
Notes:
above the genus level are often given names based on the type genus
, with a standard termination. The terminations used in forming these names depend on the kingdom, and sometimes the phylum and class, as set out in the table below. Pronunciations given are the most Anglicized
; more Latinate pronunciations are also common, particularly ɑː rather than /eɪ/ for stressed a.
Table notes:
which applies.
The following is an artificial synthesis, solely for purposes of demonstration of relative rank (but see notes), from most general to most specific:
Of these many ranks, the most basic is species. However, this is not to say that a taxon at any other rank may not be sharply defined, or that any species is guaranteed to be sharply defined. It varies from case to case. Ideally, nowadays, a taxon is intended to represent a clade
, that is, the phylogeny
of the organisms under discussion, but this is not a requirement.
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
, rank is the level (the relative position) in a taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
hierarchy
Hierarchy
A hierarchy is an arrangement of items in which the items are represented as being "above," "below," or "at the same level as" one another...
. Examples of taxonomic ranks are species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, and class
Class (biology)
In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
. Each rank subsumes under it a number of less general categories. The rank of species, and specification of the genus to which the species belongs is basic, which means that it may not be necessary to specify ranks other than these. The International Code of Zoological Nomenclature
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
defines rank as:
The level, for nomenclatural purposes, of a taxon in a taxonomic hierarchy (e.g. all families are for nomenclatural purposes at the same rank, which lies between superfamily and subfamily)
Significance
Ranks are assigned based on subjective dissimilarity, and do not fully reflect the gradational nature of variation within nature. In most cases, higher taxonomic groupings arise further back in time: not because the rate of diversification was higher in the past, but because each subsequent diversification event results in an increase of diversity and thus increases the taxonomic rank assigned by present-day taxonomists.Main ranks
"2.1. Every individual plant is treated as belonging to an indefinite number of taxa of consecutively subordinate rank, among which the rank of species (species) is basic."In his landmark publications, such as the Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
, Carolus Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
used a ranking scale limited to: kingdom, class, order, genus, species, and one rank below species. Today, nomenclature is regulated by the nomenclature codes
Nomenclature Codes
Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic nomenclature, each in their own broad field of organisms...
, which allow names divided into an indefinite number of ranks. There are seven main taxonomic ranks: kingdom, phylum or division, class, order, family, genus, species. In addition, the domain (proposed by Carl Woese
Carl Woese
Carl Richard Woese is an American microbiologist and physicist. Woese is famous for defining the Archaea in 1977 by phylogenetic taxonomy of 16S ribosomal RNA, a technique pioneered by Woese and which is now standard practice. He was also the originator of the RNA world hypothesis in 1977,...
) is now widely used as one of the fundamental ranks, although it is not mentioned in any of the nomenclature codes.
| Main taxonomic ranks | |||
| Latin | English | ||
| regio | domain Domain (biology) In biological taxonomy, a domain is the highest taxonomic rank of organisms, higher than a kingdom. According to the three-domain system of Carl Woese, introduced in 1990, the Tree of Life consists of three domains: Archaea, Bacteria and Eukarya... |
||
| regnum | kingdom Kingdom (biology) In biology, kingdom is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla or divisions in botany... |
||
| phylum | divisio | phylum Phylum In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division.... (in zoology Zoology Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct... ) |
division (in botany Botany Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses... ) |
| classis | class Class (biology) In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order... |
||
| ordo | order Order (biology) In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family... |
||
| familia | family Family (biology) In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the... |
||
| genus | genus Genus In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia... |
||
| species | species Species In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are... |
||
A taxon is usually assigned a rank when it is given its formal name. The basic rank is that of species. The next most important rank is that of genus: when an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. The third-most important rank, although it was not used by Linnaeus, is that of family.
The species name is sometimes called a binomial
Binomial nomenclature
Binomial 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, although they can be based on words from other languages...
, that is, a two-term name. For example, the zoological name for the human species is Homo sapiens: this is usually italicized in print (and underlined when italics are not available). In this case, Homo is the generic name and refers to the genus; it is capitalized; sapiens indicates the species: it is not capitalized.
Ranks in zoology
There are definitions of the following taxonomic ranks in the International Code of Zoological NomenclatureInternational Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...
: superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.
The International Code of Zoological Nomenclature divides names into "family-group names", "genus-group names" and "species-group names". The Code explicitly mentions:
----
- Superfamily
Family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
- Subfamily
- TribeTribe (biology)In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
- Subtribe
----
Genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
- SubgenusSubgenusIn biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
----
Species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
- SubspeciesSubspeciesSubspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
----
The rules in the Code apply to the ranks of superfamily to subspecies, and only to some extent to those above the rank of superfamily. In the "genus group" and "species group" no further ranks are allowed. Among zoologists, additional terms such as species group, species subgroup, species complex and superspecies are sometimes used for convenience as extra, but unofficial, ranks between the subgenus and species levels in taxa with many species (e.g., the genus Drosophila
Drosophila
Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...
).
At higher ranks (family and above) a lower level may be denoted by adding the prefix "infra", meaning lower, to the rank. For example infraorder (below suborder) or infrafamily (below subfamily).
Names of zoological taxa
- A taxon above the rank of species gets a scientific name in one part (a uninominal name).
- A species gets a name composed of two parts (a binomial name or binomenBinomenIn zoological nomenclature, a binomen , is the two-part name of a species. The term was introduced in 1953, abolishing the previously used "binomial name" . A binomen consists of a generic name and a specific epithet...
): generic name + specific name; for example Canis lupus. - A subspecies gets a name composed of three parts (a trinomial name or trinomenTrinomenIn zoological nomenclature, a trinomen , or trinominal name, refers to the name of a subspecies.A trinomen is a name consisting of three names: generic name, specific name and subspecific name. The first two parts alone form the binomen or species name. All three names are typeset in italics, and...
): generic name + specific name + subspecific nameSubspecific nameIn zoological nomenclature, a subspecific name is the third part of a trinomen. In zoology there is only one rank below that of species, namely "subspecies"....
; for example Canis lupus familiaris. As there is only one rank below that of species, no connecting term to indicate rank is used.
Ranks in botany
There are definitions of the following taxonomic ranks in the International Code of Botanical Nomenclature (ICBN): kingdom (regnum), subregnum, division or phylum (divisio, phylum), subdivisio or subphylum, class (classis), subclassis, order (ordo), subordo, family (familia), subfamilia, tribe (tribus), subtribus, genus (genus), subgenus, section (sectio), subsectio, series (series), subseries, species (species), subspecies, variety (varietas), subvarietas, form (forma), subforma.There are definitions of the following taxonomic ranks in International Code of Nomenclature for Cultivated Plants
International Code of Nomenclature for Cultivated Plants
The International Code of Nomenclature for Cultivated Plants regulates the names of cultigens...
: cultivar group, cultivar.
According to Art 3.1 of the ICBN the most important ranks of taxa are: kingdom, division or phylum, class, order, family, genus, and species. According to Art 4.1 the secondary ranks of taxa are tribe, section, series, variety and form. There is an indeterminate number of ranks. The ICBN explicitly mentions:
----
primary ranks
- secondary ranks
- further ranks
----
kingdom (regnum)
-
- subregnum
division or phylum (divisio, phylum)
-
- subdivisio or subphylum
class (classis)
-
- subclassis
order (ordo)
-
- subordo
----
family (familia)
-
- subfamilia
- tribe (tribus)
- subtribus
genus (genus)
-
- subgenus
- section (sectio)
- subsectio
- series (series)
- subseries
species (species)
-
- subspecies
- variety (varietas)
- subvarietas
- form (forma)
- subforma
----
The rules in the ICBN apply primarily to the ranks of family and below, and only to some extent to those above the rank of family. Also see descriptive botanical names
Descriptive botanical names
Descriptive botanical names are names that are governed by Article 16 of the International Code of Botanical Nomenclature , which rules that a name above the rank of family may be either descriptive or formed from the name of an included family...
.
Names of botanical taxa
Of the botanical names used by LinnaeusCarolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...
only names of genera, species and varieties are still used.
Taxa at the rank of genus and above get a botanical name
Botanical name
A botanical name is a formal scientific name conforming to the International Code of Botanical Nomenclature and, if it concerns a plant cultigen, the additional cultivar and/or Group epithets must conform to the International Code of Nomenclature for Cultivated Plants...
in one part (unitary name); those at the rank of species and above (but below genus) get a botanical name in two parts (binary name); all taxa below the rank of species get a botanical name in three parts (an infraspecific name
Infraspecific name (botany)
In botany, an infraspecific name is the name for any taxon below the rank of species, i.e. an infraspecific taxon. The scientific names of plants are regulated by the International Code of Botanical Nomenclature...
).
For hybrids getting a hybrid name
Hybrid name
In botanical nomenclature, a hybrid may be given a hybrid name, which is a special kind of botanical name. The ICBN provides the following options in dealing with a hybrid:...
, the same ranks apply, preceded by "notho", with nothogenus as the highest permitted rank. (The hybrid's nothotaxon is an alias for a list of all of the taxa which are ancestral to the hybrid.)
Out-dated names for botanical ranks
If a different term for the rank was used in an in old publication, but the intention is clear, botanical nomenclature specifies certain substitutions:- If names were "intended as names of orders, but published with their rank denoted by a term such as": "cohors" [Latin for "cohort"], "nixus", "alliance", or "Reihe" instead of "order" (Article 17.2), they are treated as names of orders.
- "Family" is substituted for "order" (ordo) or "natural order" (ordo naturalis) under certain conditions where the modern meaning of "order" was not intended. (Article 18.2)
- "Subfamily is substituted for "suborder" (subordo) under certain conditions where the modern meaning of "suborder" was not intended. (Article 19.2)
- In a publication prior to 1 January 1890, if only one infraspecific rank is used, it is considered to be that of variety. (Article 35.4) This commonly applies to publications that labelled infraspecific taxa with Greek letters, α, β, γ, ...
Examples
Classifications of five species follow: the fruit flyDrosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...
so familiar in genetics laboratories (Drosophila melanogaster), human
Human
Humans are the only living species in the Homo genus...
s (Homo sapiens), the pea
Pea
A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking...
s used by Gregor Mendel
Gregor Mendel
Gregor Johann Mendel was an Austrian scientist and Augustinian friar who gained posthumous fame as the founder of the new science of genetics. Mendel demonstrated that the inheritance of certain traits in pea plants follows particular patterns, now referred to as the laws of Mendelian inheritance...
in his discovery of genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
(Pisum sativum), the "fly agaric" mushroom Amanita muscaria
Amanita muscaria
Amanita muscaria, commonly known as the fly agaric or fly amanita , is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita...
, and the bacterium Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
. The eight major ranks are given in bold; a selection of minor ranks are given as well.
| Rank | Fruit fly Drosophila melanogaster Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W... |
Human Human Humans are the only living species in the Homo genus... |
Pea Pea A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking... |
Fly Agaric Amanita muscaria Amanita muscaria, commonly known as the fly agaric or fly amanita , is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita... |
E. coli Escherichia coli Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls... |
|---|---|---|---|---|---|
| Domain Domain (biology) In biological taxonomy, a domain is the highest taxonomic rank of organisms, higher than a kingdom. According to the three-domain system of Carl Woese, introduced in 1990, the Tree of Life consists of three domains: Archaea, Bacteria and Eukarya... |
Eukarya Eukaryote A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear... |
Eukarya Eukaryote A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear... |
Eukarya Eukaryote A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear... |
Eukarya Eukaryote A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear... |
Bacteria Bacteria Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals... |
| Kingdom Kingdom (biology) In biology, kingdom is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla or divisions in botany... |
Animal Animal Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and... ia |
Animal Animal Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and... ia |
Plant Plant Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or... ae |
Fungi Fungus A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria... |
Bacteria Bacteria Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals... |
| Phylum Phylum In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division.... or Division |
Arthropod Arthropod An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others... a |
Chordata Chordate Chordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail... |
Magnoliophyta Flowering plant The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies... |
Basidiomycota Basidiomycota Basidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya within the Kingdom Fungi... |
Proteobacteria Proteobacteria The Proteobacteria are a major group of bacteria. They include a wide variety of pathogens, such as Escherichia, Salmonella, Vibrio, Helicobacter, and many other notable genera.... |
| Subphylum Subphylum In life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum.Not all phyla are divided into subphyla... or subdivision |
Hexapoda Hexapoda The subphylum Hexapoda constitutes the largest grouping of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura . The Collembola are very abundant in terrestrial environments... |
Vertebrata Vertebrate Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds... |
Magnoliophytina | Agaricomycotina Agaricomycotina The subphylum Agaricomycotina, also known as the hymenomycetes, is one of three taxa of the fungal division Basidiomycota . The Agaricomycotina contain some 20,000 species, and about 98% of these are in the class Agaricomycetes: most of the fungi known as mushrooms, including the bracket fungi and... |
|
| Class Class (biology) In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order... |
Insect Insect Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae... a |
Mammal Mammal Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young... ia |
Magnoliopsida Magnoliopsida Magnoliopsida is a valid botanical name for a class of flowering plants. By definition the class will include the family Magnoliaceae, but its circumscription can otherwise vary, being more inclusive or less inclusive depending upon the classification system being discussed.-Cronquist and... |
Agaricomycetes Agaricomycetes Agaricomycetes is a class of fungi. The taxon is roughly identical to that defined for the Homobasidiomycetes by Hibbett & Thorn, with the inclusion of Auriculariales and Sebacinales. It includes not only mushrooms but also most species placed in the deprecated taxa Gasteromycetes and... |
Gammaproteobacteria Gammaproteobacteria Gammaproteobacteria is a class of several medically, ecologically and scientifically important groups of bacteria, such as the Enterobacteriaceae , Vibrionaceae and Pseudomonadaceae. An exceeding number of important pathogens belongs to this class, e.g... |
| Subclass | Pterygota Pterygota Pterygota is a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless .... |
Theria Theria Theria is a subclass of mammals that give birth to live young without using a shelled egg, including both eutherians and metatherians . The only omitted extant mammal group is the egg-laying monotremes.... |
Rosidae Rosidae Under the International Code of Botanical Nomenclature , Rosidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used; the only requirement being that it includes the family Rosaceae.... |
Agaricomycetidae Agaricomycetidae Agaricomycetidae is a subclass of mushrooms, in the phylum of Basidiomycota. The MycoBank number for this subclass is MB501298. The name Agaricomycetidae was also named by Locquin , but his publication did not contain a Latin diagnosis and it is therefore invalid under the International Code of... |
|
| Order Order (biology) In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family... |
Diptera Fly True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax... |
Primate Primate A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment... s |
Fabales Fabales Fabales is an order of flowering plants. It is included in the rosid group of the eudicots in the Angiosperm Phylogeny Group II classification system... |
Agaricales Agaricales The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record... |
Enterobacteriales Enterobacteriaceae The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the... |
| Suborder | Brachycera Brachycera Brachycera is a suborder of Diptera. It is a major suborder consisting of around 120 families. The most distinguishing characteristic of the suborder is reduced antenna segmentation... |
Haplorrhini Haplorrhini The haplorhines, the "dry-nosed" primates , are members of the Haplorhini clade: the prosimian tarsiers and the anthropoids... |
Fabineae | Agaricineae | |
| Family Family (biology) In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the... |
Drosophilidae Drosophilidae Drosophilidae is a diverse, cosmopolitan family of flies, which includes fruit flies. Another family of flies called Tephritidae also includes fruit flies. The best known species of Drosophilidae is Drosophila melanogaster, within the genus Drosophila, and this species Is used extensively for... |
Hominidae | Fabaceae Fabaceae The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species... |
Amanitaceae Amanitaceae Amanitaceae are a family of fungi or mushrooms. The family, also commonly called the Amanita family, is in order Agaricales, gilled mushrooms... |
Enterobacteriaceae Enterobacteriaceae The Enterobacteriaceae is a large family of bacteria that includes many of the more familiar pathogens, such as Salmonella, Escherichia coli, Yersinia pestis, Klebsiella and Shigella. This family is the only representative in the order Enterobacteriales of the class Gammaproteobacteria in the... |
| Subfamily | Drosophilinae Drosophilinae The Drosophilinae are the largest subfamily in the Drosophilidae. The other subfamily is the Steganinae.-Phylogeny:Many molecular studies have addressed small parts of the phylogenetic tree. Most of these studies are limited to species of the genus Drosophila... |
Homininae Homininae Homininae is a subfamily of Hominidae, which includes humans, gorillas and chimpanzees, and some extinct relatives; it comprises all those hominids, such as Australopithecus, that arose after the split from orangutans . Our family tree, which has 3 main branches leading to chimpanzees, humans and... |
Faboideae Faboideae Faboideae is a subfamily of the flowering plant family Fabaceae or Leguminosae. One acceptable alternative name for the subfamily is Papilionoideae.... |
Amanitoideae Amanitoideae Amanitoideae is a subfamily of the fungi or mushroom family Amanitaceae.... |
|
| Genus Genus In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia... |
Drosophila Drosophila Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit... |
Homo Homo (genus) Homo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old, evolving from australopithecine ancestors with the appearance of Homo habilis.... |
Pisum Pisum Pisum is a genus of the family Fabaceae, native to southwest Asia and northeast Africa. It contains one to five species, depending on taxonomic interpretation; the International Legume Database accepts three species, one with two subspecies :... |
Amanita Amanita The genus Amanita contains about 600 species of agarics including some of the most toxic known mushrooms found worldwide. This genus is responsible for approximately 95% of the fatalities resulting from mushroom poisoning, with the death cap accounting for about 50% on its own... |
Escherichia Escherichia Escherichia is a genus of Gram-negative, non-spore forming, facultatively anaerobic, rod-shaped bacteria from the family Enterobacteriaceae. In those species which are inhabitants of the gastrointestinal tracts of warm-blooded animals, Escherichia species provide a portion of the... |
| Species Species In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are... |
D. melanogaster Drosophila melanogaster Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W... |
H. sapiens Human Humans are the only living species in the Homo genus... |
P. sativum Pea A pea is most commonly the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas. Peapods are botanically a fruit, since they contain seeds developed from the ovary of a flower. However, peas are considered to be a vegetable in cooking... |
A. muscaria Amanita muscaria Amanita muscaria, commonly known as the fly agaric or fly amanita , is a poisonous and psychoactive basidiomycete fungus, one of many in the genus Amanita... |
E. coli Escherichia coli Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls... |
Notes:
- The ranks of higher taxa, especially intermediate ranks, are prone to revision as new information about relationships is discovered. For example, the traditional classification of primates (class Mammalia — subclass Theria — infraclass Eutheria — order Primates) has been modified by new classifications such as McKenna and Bell (class Mammalia — subclass Theriformes — infraclass Holotheria) with Theria and Eutheria assigned lower ranks between infraclass and the order Primates. See mammal classificationMammal classificationMammalia is a class of animal within the Phylum Chordata. Mammal classification has been through several iterations since Carolus Linnaeus initially defined the class. Many earlier ideas have been completely abandoned by modern taxonomists, among these are the idea that bats are related to birds...
for a discussion. These differences arise because there are only a small number of ranks available and a large number of branching points in the fossil record. - Within species further units may be recognised. Animals may be classified into subspecies (for example, Homo sapiens sapiens, modern humans) or morphPolymorphism (biology)Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
s (for example Corvus corax varius morpha leucophaeus, the Pied Raven). Plants may be classified into subspecies (for example, Pisum sativum subsp. sativum, the garden pea) or varieties (for example, Pisum sativum var. macrocarpon, snow pea), with cultivated plants getting a cultivarCultivarA cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
name (for example, Pisum sativum var. macrocarpon 'Snowbird'). Bacteria may be classified by strainsStrain (biology)In biology, a strain is a low-level taxonomic rank used in three related ways.-Microbiology and virology:A strain is a genetic variant or subtype of a micro-organism . For example, a "flu strain" is a certain biological form of the influenza or "flu" virus...
(for example Escherichia coli O157:H7Escherichia coli O157:H7Escherichia coli O157:H7 is an enterohemorrhagic strain of the bacterium Escherichia coli and a cause of foodborne illness. Infection often leads to hemorrhagic diarrhea, and occasionally to kidney failure, especially in young children and elderly persons...
, a strain that can cause food poisoningFoodborne illnessFoodborne illness is any illness resulting from the consumption of contaminated food, pathogenic bacteria, viruses, or parasites that contaminate food, as well as chemical or natural toxins such as poisonous mushrooms.-Causes:Foodborne illness usually arises from improper handling, preparation, or...
). - MnemonicMnemonicA mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...
s are available at mnemonic-device.eu and thefreedictionary.com.
Terminations of names
TaxaTaxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
above the genus level are often given names based on the type genus
Type genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
, with a standard termination. The terminations used in forming these names depend on the kingdom, and sometimes the phylum and class, as set out in the table below. Pronunciations given are the most Anglicized
Traditional English pronunciation of Latin
The traditional English pronunciation of Latin, and Classical Greek words borrowed through Latin, is the way the Latin language was traditionally pronounced by speakers of English until the early 20th century....
; more Latinate pronunciations are also common, particularly ɑː rather than /eɪ/ for stressed a.
| Rank | Plant Plant Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or... s |
Algae Algae Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many... |
Fungi Fungus A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria... |
Animal Animal Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and... s |
Bacteria Bacteria Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals... |
|---|---|---|---|---|---|
| Division/Phylum | -phyta ˈfaɪtə | -mycota /maɪˈkoʊtə/ | |||
| Subdivision/Subphylum | -phytina /fɨˈtaɪnə/ | -mycotina /maɪkɵˈtaɪnə/ | |||
| Class | -opsida /ˈɒpsɨdə/ | -phyceae /ˈfaɪʃiː/ | -mycetes /maɪˈsiːtiːz/ | -ia /iə/ | |
| Subclass | -idae /ɨdiː/ | -phycidae /ˈfɪsɨdiː/ | -mycetidae /maɪˈsɛtɨdiː/ | -idae /ɨdiː/ | |
| Superorder | -anae /ˈeɪniː/ | ||||
| Order | -ales /ˈeɪliːz/ | -ales /ˈeɪliːz/ | |||
| Suborder | -ineae /ˈɪnɨ.iː/ | -ineae /ˈɪnɨ.iː/ | |||
| Infraorder | -aria /ˈɛəri.ə/ | ||||
| Superfamily | -acea /ˈeɪʃə/ | -oidea /ˈɔɪdi.ə/ | |||
| Epifamily | -oidae /ˈɔɪdiː/ | ||||
| Family | -aceae /ˈeɪʃiː/ | -idae /ɨdiː/ | -aceae /ˈeɪʃiː/ | ||
| Subfamily | -oideae /ˈɔɪdɨ.iː/ | -inae /ˈaɪniː/ | -oideae /ˈɔɪdɨ.iː/ | ||
| Infrafamily | -itae /ˈɔɪtɨ.iː/ | ||||
| Tribe | -eae /ɨ.iː/ | -ini /ˈaɪnaɪ/ | -eae /ɨ.iː/ | ||
| Subtribe | -inae /ˈaɪniː/ | -ina /ˈaɪnə/ | -inae /ˈaɪniː/ | ||
| Infratribe | -ita /ˈaɪtə/ | ||||
Table notes:
- In botany and mycology names at the rank of family and below are based on the name of a genus, sometimes called the type genusType genusIn biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
of that taxon, with a standard ending. For example, the rose family RosaceaeRosaceaeRosaceae are a medium-sized family of flowering plants, including about 2830 species in 95 genera. The name is derived from the type genus Rosa. Among the largest genera are Alchemilla , Sorbus , Crataegus , Cotoneaster , and Rubus...
is named after the genus Rosa, with the standard ending "-aceae" for a family. Names above the rank of family are formed from a family name, or are descriptive (like GymnospermGymnospermThe gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...
ae or FungiFungusA fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
). - For animals, there are standard suffixes for taxa only up to the rank of superfamily.
- Forming a name based on a generic name may be not straightforward. For example, the LatinLatinLatin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
"homo" has the genitive "hominis", thus the genus "Homo" (human) is in the Hominidae, not "Homidae". - The ranks of epifamily, infrafamily and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions. Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings. The suffixes listed here are regular, but informal.
All ranks
There is an indeterminate number of ranks, as a taxonomist may invent a new rank at will, at any time, if they feel this is necessary. In doing so, there are some restrictions, which will vary with the nomenclature codeNomenclature Codes
Nomenclature codes or codes of nomenclature are the various rulebooks that govern biological taxonomic nomenclature, each in their own broad field of organisms...
which applies.
The following is an artificial synthesis, solely for purposes of demonstration of relative rank (but see notes), from most general to most specific:
- DomainDomain (biology)In biological taxonomy, a domain is the highest taxonomic rank of organisms, higher than a kingdom. According to the three-domain system of Carl Woese, introduced in 1990, the Tree of Life consists of three domains: Archaea, Bacteria and Eukarya...
or Empire- KingdomKingdom (biology)In biology, kingdom is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla or divisions in botany...
- Subkingdom
- Branch
- Infrakingdom
- Branch
- Subkingdom
- Kingdom
- Superphylum (or Superdivision in botany)
- Phylum (or Division in botany)
- SubphylumSubphylumIn life, a subphylum is a taxonomic rank intermediate between phylum and superclass. The rank of subdivision in plants and fungi is equivalent to subphylum.Not all phyla are divided into subphyla...
(or Subdivision in botany)- Infraphylum (or Infradivision in botany)
- Microphylum
- Infraphylum (or Infradivision in botany)
- Subphylum
- Phylum (or Division in botany)
- Supercohort (botany)
- Cohort (botany)
- Subcohort (botany)
- Infracohort (botany)
- Subcohort (botany)
- Cohort (botany)
- SuperclassClass (biology)In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
- ClassClass (biology)In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
- SubclassClass (biology)In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...
- Infraclass
- Parvclass
- Infraclass
- Subclass
- Class
- Superdivision (zoology)
- Division (zoology)
- Subdivision (zoology)
- Infradivision (zoology)
- Subdivision (zoology)
- Division (zoology)
- Superlegion (zoology)
- LegionLegion (biology)The legion, in biological taxonomy, is a non-obligatory taxonomic rank within the Linnaean hierarchy which is subordinate to the class but superordinate to the cohort...
(zoology)- Sublegion (zoology)
- Infralegion (zoology)
- Sublegion (zoology)
- Legion
- Supercohort (zoology)
- Cohort (zoology)
- Subcohort (zoology)
- Infracohort (zoology)
- Subcohort (zoology)
- Cohort (zoology)
- Gigaorder (zoology)
- Magnorder or Megaorder (zoology)
- Grandorder or Capaxorder (zoology)
- Mirorder or Hyperorder (zoology)
- Superorder
- Series (for fishes)
- OrderOrder (biology)In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
- Parvorder (position in some zoological classifications)
- Nanorder (zoology)
- Hypoorder (zoology)
- Minorder (zoology)
- Suborder
- Infraorder
- Parvorder (usual position) or Microorder (zoology)
- Infraorder
- Suborder
- Minorder (zoology)
- Hypoorder (zoology)
- Nanorder (zoology)
- Parvorder (position in some zoological classifications)
- Order
- Series (for fishes)
- Superorder
- Mirorder or Hyperorder (zoology)
- Grandorder or Capaxorder (zoology)
- Magnorder or Megaorder (zoology)
- Section (zoology)
- Subsection (zoology)
- Gigafamily (zoology)
- Megafamily (zoology)
- Grandfamily (zoology)
- Hyperfamily (zoology)
- Superfamily
- Epifamily (zoology)
- Series (for Lepidoptera)
- Group (for Lepidoptera)
- FamilyFamily (biology)In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
- Subfamily
- Infrafamily
- Subfamily
- Family
- Group (for Lepidoptera)
- Series (for Lepidoptera)
- Epifamily (zoology)
- Superfamily
- Hyperfamily (zoology)
- Grandfamily (zoology)
- Megafamily (zoology)
- Supertribe
- TribeTribe (biology)In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
- Subtribe
- Infratribe
- Subtribe
- Tribe
- GenusGenusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
- SubgenusSubgenusIn biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
- Section (botany)
- Subsection (botany)
- Series (botany)
- Subseries (botany)
- Series (botany)
- Subsection (botany)
- Section (botany)
- Subgenus
- SuperspeciesCryptic species complexIn biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each other—but whose morphology is very similar ....
or Species-group- SpeciesSpeciesIn biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
- SubspeciesSubspeciesSubspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
(or Forma Specialis for fungi, or Variety for bacteria)- Variety (botany) or Form/Morph (zoology)
- SubvarietySubvarietyIn botanical nomenclature, a subvariety is a taxonomic rank below that of variety but above that of form : it is an infraspecific taxon. Its name consists of three parts: a genus name, a specific epithet and an infraspecific epithet. To indicate the rank, the abbreviation "subvar." should be put...
(botany)- FormForm (botany)In botanical nomenclature, a form is one of the "secondary" taxonomic ranks, below that of variety, which in turn is below that of species; it is an infraspecific taxon...
(botany)- Subform (botany)
- Form
- Subvariety
- Variety (botany) or Form/Morph (zoology)
- Subspecies
- Species
Of these many ranks, the most basic is species. However, this is not to say that a taxon at any other rank may not be sharply defined, or that any species is guaranteed to be sharply defined. It varies from case to case. Ideally, nowadays, a taxon is intended to represent a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
, that is, the phylogeny
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
of the organisms under discussion, but this is not a requirement.