Temporal range:
FortunianHolocene, 535–0 Ma
The glass catfish (Kryptopterus vitreolus) is one of the few chordates with a visible backbone. The spinal cord is housed within its backbone.
Scientific classification e
Haeckel, 1874[1][2]

And see text

A chordate (t/) is an animal constituting the phylum Chordata ([kɔrˈdata]). During some period of their life cycle, chordates possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail: these five anatomical features define this phylum. Chordates are also bilaterally symmetric; and have a coelom, metameric segmentation, and a circulatory system.

The Chordata and Ambulacraria together form the superphylum Deuterostomia. Chordates are divided into three subphyla: Vertebrata (fish, amphibians, reptiles, birds, and mammals); Tunicata (salps and sea squirts); and Cephalochordata (which includes lancelets). There are also extinct taxa such as the Vetulicolia. Hemichordata (which includes the acorn worms) has been presented as a fourth chordate subphylum, but now is treated as a separate phylum: hemichordates and Echinodermata form the Ambulacraria, the sister phylum of the Chordates. Of the more than 65,000 living species of chordates, about half are bony fish that are members of the superclass Osteichthyes.

Chordate fossils have been found from as early as the Cambrian explosion, 541 million years ago. Cladistically (phylogenetically), vertebrates – chordates with the notochord replaced by a vertebral column during development – are considered to be a subgroup of the clade Craniata, which consists of chordates with a skull. The Craniata and Tunicata compose the clade Olfactores. (See diagram under Phylogeny.)


Chordates form a phylum of animals that are defined by having at some stage in their lives all of the following anatomical features:[3]

  • A notochord, a fairly stiff rod of cartilage that extends along the inside of the body. Among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail.
  • A dorsal neural tube. In fish and other vertebrates, this develops into the spinal cord, the main communications trunk of the nervous system.
  • Pharyngeal slits. The pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, but in some other chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live.
  • Post-anal tail. A muscular tail that extends backwards behind the anus.
  • An endostyle. This is a groove in the ventral wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus.[4] It also stores iodine, and may be a precursor of the vertebrate thyroid gland.[3]

There are soft constraints that separate chordates from certain other biological lineages, but are not part of the formal definition:

1 = bulge in spinal cord ("brain")
4 = post-anal tail
5 = anus
9 = space above pharynx
11 = pharynx
12 = vestibule
13 = oral cirri
14 = mouth opening
16 = light sensor
17 = nerves
18 = metapleural fold
19 = hepatic caecum (liver-like sack)
Anatomy of the cephalochordate Amphioxus. Bolded items are components of all chordates at some point in their lifetimes, and distinguish them from other phyla.
Other Languages
Afrikaans: Rugstringdiere
Alemannisch: Chordatiere
አማርኛ: አምደስጌ
العربية: حبليات
aragonés: Chordata
অসমীয়া: ক'ৰডাটা
asturianu: Chordata
azərbaycanca: Xordalılar
বাংলা: কর্ডাটা
Bân-lâm-gú: Chek-soh tōng-bu̍t
башҡортса: Хордалылар
беларуская: Хордавыя
беларуская (тарашкевіца)‎: Хордавыя
भोजपुरी: कार्डेट
български: Хордови
bosanski: Hordati
brezhoneg: Chordata
буряад: Хүбшэтэн
català: Cordats
čeština: Strunatci
Cymraeg: Cordog
dansk: Chordater
Deutsch: Chordatiere
Ελληνικά: Χορδωτά
español: Chordata
Esperanto: Ĥorduloj
euskara: Kordatu
فارسی: طنابداران
Fiji Hindi: Chordate
føroyskt: Chordata
français: Chordata
Gaeilge: Chordates
Gaelg: Chordata
Gàidhlig: Chordata
galego: Cordados
客家語/Hak-kâ-ngî: Chit-sok thung-vu̍t
한국어: 척삭동물
հայերեն: Քորդավորներ
हिन्दी: रज्जुकी
hrvatski: Svitkovci
Ilokano: Chordata
Bahasa Indonesia: Chordata
interlingua: Chordata
íslenska: Seildýr
italiano: Chordata
עברית: מיתרניים
Jawa: Chordata
ಕನ್ನಡ: ಕಾರ್ಡೇಟ್
ქართული: ქორდიანები
қазақша: Хордалылар
kernowek: Chordata
Kiswahili: Kodata
Kreyòl ayisyen: Kòde
Кыргызча: Хордалуу
Latina: Chordata
latviešu: Hordaiņi
Lëtzebuergesch: Chordadéieren
lietuvių: Chordiniai
Ligure: Chordata
Limburgs: Chordabieste
Lingua Franca Nova: Cordato
la .lojban.: skoselti'e
македонски: Хордови
മലയാളം: കോർഡേറ്റ
Malti: Chordata
მარგალური: ქორდიანეფი
Bahasa Melayu: Kordata
Mìng-dĕ̤ng-ngṳ̄: Cék-só̤h dông-ŭk
монгол: Хөвчтөн
Nederlands: Chordadieren
日本語: 脊索動物
Nordfriisk: Ragstringdiarten
norsk nynorsk: Ryggstrengdyr
Novial: Chordata
occitan: Chordata
oʻzbekcha/ўзбекча: Xordalilar
ਪੰਜਾਬੀ: ਤੰਦਧਾਰੀ
پنجابی: کورڈیٹ
Перем Коми: Мышксöнаэз
Piemontèis: Chordata
Plattdüütsch: Ruggensnarendeerter
polski: Strunowce
português: Cordados
română: Cordate
Runa Simi: Wasa tiwlliyuq
русиньскый: Хордовы
русский: Хордовые
саха тыла: Хордалыктар
Scots: Chordate
shqip: Chordate
sicilianu: Chordata
Simple English: Chordate
slovenčina: Chordáty
slovenščina: Strunarji
کوردی: مازەداران
српски / srpski: Хордати
srpskohrvatski / српскохрватски: Svitkovci
Basa Sunda: Chordata
Tagalog: Chordata
Taqbaylit: Timzikrin
татарча/tatarça: Хордалылар
తెలుగు: కార్డేటా
тоҷикӣ: Танобдорон
lea faka-Tonga: Monumanu filo siliva
Türkçe: Kordalılar
українська: Хордові
اردو: حبلیات
West-Vlams: Chordabêestn
Winaray: Chordata
吴语: 脊索动物
ייִדיש: כארדאטן
粵語: 脊索動物
žemaitėška: Chuordėnē
中文: 脊索动物