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Taxonomic rank (rank, category, taxonomic category) is abstract term used in taxonomy used in scientific classification of organism. Taxonomic rank indicates the level of taxon in taxonomic hierarchy. Taxons ranked in certain taxonomic ranks are real groups of real organisms at real classification level.

Definition of taxonomic rank (there called only a rank) in International Code of Zoological Nomenclature:

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). The ranks of the family group, the genus group, and the species group at which nominal taxa may be established are stated in Articles 10.3, 10.4, 35.1, 42.1 and 45.1.

—International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp.

History[edit | edit source]

Carl Linnaeus devised Linnaean taxonomy and he used five ranks: class, order, genus, species, and variety.

Today, nomenclature is regulated by Nomenclature Codes, which allows names divided into exactly defined ranks. Despite this there are slightly different ranks for zoology and different ranks for botany.

Ranks in zoology and in botany[edit | edit source]

Main article: Rank (zoology)

There are definitions of the following taxonomic ranks in International Code of Zoological Nomenclature: superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.

There are definitions of the following taxonomic ranks in International Code of Botanical Nomenclature: 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 definition of following taxonomic ranks in International Code of Nomenclature for Cultivated Plants: cultivar group, cultivar.

Main taxonomic ranks[edit | edit source]

There are 8 main taxonomic ranks: domain, kingdom, phylum or division1,class, order, family, genus, species.

Main taxonomic ranks in more languages (zoology and botany)
Latin English Vietnamese German Spanish French Greek Arabic Mandarin
regnum kingdom   Reich reino règne βασίλειο مملكة  
phylum phylum1 Giới Stamm filo phylum   門 (動物)
divisio division2 Ngành Abteilung división embranchement     門 (植物)
classis class Lớp Klasse clase classe ομοταξία  
ordo order Bộ Ordnung orden ordre τάξη
familia family Họ Familie familia famille οικογένεια عائلة
genus genus Chi Gattung género genre γένος جنس
species species Loài Art especie espèce είδος نوع  
Notes to table
1 Phylum is used in zoology. It is at the same level as division in botany. 2 Preferred before to phylum in botany, that is accounted as identical.

Examples[edit | edit source]

The usual classifications of five species follow: the fruit fly so familiar in genetics laboratories (Drosophila melanogaster), humans (Homo sapiens), the peas 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.

Rank Fruit fly Human Pea Fly Agaric E. coli
Domain Eukarya Eukarya Eukarya Eukarya Bacteria
Kingdom Animalia Animalia Plantae Fungi Monera
Phylum or Division Arthropoda Chordata Magnoliophyta Basidiomycota Proteobacteria
Subphylum or subdivision Hexapoda Vertebrata Magnoliophytina Agaricomycotina
Class Insecta Mammalia Magnoliopsida Agaricomycetes Gammaproteobacteria
Subclass Pterygota Theria Magnoliidae Agaricomycetidae
Order Diptera Primates Fabales Agaricales Enterobacteriales
Suborder Brachycera Haplorrhini Fabineae Agaricineae
Family Drosophilidae Hominidae Fabaceae Amanitaceae Enterobacteriaceae
Subfamily Drosophilinae Homininae Faboideae Amanitoideae
Genus Drosophila Homo Pisum Amanita Escherichia
Species D. melanogaster H. sapiens P. sativum A. muscaria E. coli

Table 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 classification 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 morphs (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 cultivar name (for example, Pisum sativum var. macrocarpon 'Snowbird'). Bacteria may be classified by strains (for example Escherichia coli O157:H7, a strain that can cause food poisoning).
  • A mnemonic for remembering the order of the taxa is: Do Koalas Prefer Chocolate Or Fruit, Generally Speaking? Another easy one is Damn, Kinky People Can Often Find Great Sex. Other mnemonics are available at[1] and.[2]

Terminations of names[edit | edit source]

Taxa 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.

Rank Plants Algae Fungi Animals Bacteria [3]
Division/Phylum -phyta -mycota
Subdivision/Subphylum -phytina -mycotina
Class -opsida -phyceae -mycetes -ia
Subclass -idae -phycidae -mycetidae -idae
Superorder -anae
Order -ales -ales
Suborder -ineae -ineae
Infraorder -aria
Superfamily -acea -oidea
Epifamily -oidae
Family -aceae -idae -aceae
Subfamily -oideae -inae -oideae
Infrafamily -odd[verification needed]
Tribe -eae -ini -eae
Subtribe -inae -ina -inae
Infratribe -ad

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 genus of that taxon, with a standard ending. For example, the rose family Rosaceae 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 Gymnospermae or Fungi).
  • For animals, there are standard suffixes for taxa only up to the rank of superfamily.[4]
  • Forming a name based on a generic name may be not straightforward. For example, the Latin "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.[5]

All taxonomic ranks[edit | edit source]

There are written all taxonomic ranks including those ones that are not in use today or those ones that are identical with another ranks.

All taxonomic ranks in more languages (zoology and botany)
Latin English German French Notes
  superdomain      
regio domain Domäne domaine  
  subdomain      
  infradomain      
imperium empire   empire  
superregnum superkingdom      
  suprakingdom      
  midkingdom      
regnum kingdom Reich règne  
subregnum subkingdom Unterreich sous-règne  
  interkingdom      
  branch      
  infrakingdom      
superphylum superphylum Stammgruppe, Überstamm super-phylum  
  supraphylum      
  midphylum      
phylum phylum Stamm phylum  
subphylum subphylum Unterstamm sous-phylum  
infraphylum subphylum      
divisio division Abteilung embranchement, division  
subdivisio subdivision Unterabteilung sous-embranchement  
claudius claudius      
superclassis superclass Überklasse super-classe  
  grade Reihe    
classis class Klasse classe  
subclassis subclass Unterklasse sous-classe  
  infraclass   infra-classe  
parvclassis parvclass      
superdivisio superdivision Überabteilung super-embranchment  
divisio division Abteilung embranchement, division  
subdivisio subdivision Unterabteilung sous-embranchement  
sectio section      
  subsection      
  group      
  subgroup      
  superlegion      
legio legion      
  sublegion      
  infralegion      
supercohos supercohort      
cohors cohort      
subcohors subcohort      
  magnorder      
superordo superorder Überordnung superordre  
  series      
  subseries      
  grandorder      
  gigaorder      
  megaorder      
  mirorder      
ordo order Ordnung ordre  
hyperordo hyperorder      
subordo suborder Unterordnung sous-ordre  
infraordo infraorder Infraordnung infraordre  
  parvorder      
falanx        
cohors cohort      
superfamilia superfamily Überfamilie superfamille  
  family group      
familia family Familie famille  
  subfamily group      
subfamilia subfamily Unterfamilie sous-famille  
  infrafamily      
supertribus supertribe      
tribus tribe Tribus tribu  
subtribus subtribe Subtribus sous-tribu  
  infratribe      
supergenus supergenus      
  genus group      
genus genus Gattung genre  
subgenus subgenus Untergattung sous-genre  
  infragenus      
supersectio supersection      
sectio section   section  
subsectio subsection      
  infrasection      
  superseries      
series series   série  
  subseries      
  infraseries      
superspecies superspecies      
  complex      
  species group      
  species subgroup      
  aggregate      
  synklepton      
species species Art espèce  
  microspecies      
klepton klepton      
  aggregate      
subspecies subspecies Unterart (Rasse) sous-espèce  
  infraspecies      
  group      
hybrid hybrid      
convarietas convariety      
supervarietas supervariety      
varietas variety Varietät variété  
subvarietas subvariety      
  infravariety      
natio        
superforma superform      
forma, morpha form Zuchtform forme  
subforma subform      
  infraform      
  cultivar group      
  cultivar      
  group of breeds      
  section of breeds      
  breed, race      
  strain      
aberratio aberration      
  serogroup      
  serotype   sérovar  
  biotype   biovar  
  pathotype   pathovar  
  population      
lusus lusus      
Notes to table
Level in plant taxonomy. Level in animal taxonomy.

References[edit | edit source]

  1. mnemonic-device.eu
  2. thefreedictionary.com.
  3. Bacteriologocal Code (1990 Revision)
  4. ICZN article 27.2
  5. As supplied by Eugene S. Gaffney & Peter A. Meylan (1988), "A phylogeny of turtles", in M.J. Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds 157-219 (Oxford: Clarendon Press).
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