ChordataIntroductionChordata are almost equal to
Vertebrata and
Deuterostomia.
ZoologyThey have a bilateral body plan: a head and tail end, a front and back side.
They are are deuterostomia, meaning that the anus forms before the mouth.
They are coelomates, having a fluid-filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm.
They have a notochord, a fairly stiff rod of cartilage that extends along the inside of the body.
They have a dorsal neural tube.
They have pharyngeal slits; in some chordates they are part of a filter-feeding system that extracts particles of food from the water in which the animals live.
They have a post-anal muscular tail.
They have an endostyle, a groove in the ventral wall of the pharynx; it filters food, produces mucus, transports food to the esophagus; it also stores iodine, as a precursor of the vertebrate thyroid gland.
Clades
1
Cephalochordata: Acraniata, Llancelets, 30 species.
2 Olfactores
2.1
Tunicata: Urochordata, tunicates, 3000 species.
2.2
Vertebrata: Craniata, Vertebrates, animals with backbones; 57674 species.
2.2.1
Agnatha: jawless vertebrates; 100+ species.
2.2.2
Chondrichthyes: cartilaginous fishes.
2.2.3
Osteichthyes: bony fishes.
2.2.4
Amphibia: amphibians.
2.2.5
Reptilia: reptiles.
2.2.6
Aves: birds.
2.2.7
Mammalia: mammals.