Vertebrate

Vertebratavertebratesvertebralvertebrate animalsvertebraevertebrate species vertebrate collectionbackbonebeastmicrovertebrates
Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones).wikipedia
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Animal

Animaliaanimalsmetazoa
Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones).
The Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes, arthropods, and molluscs—and the deuterostomes, containing both the echinoderms as well as the chordates, the latter containing the vertebrates.

Frog

frogsAnuraanuran
Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, at up to 33 m. Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns.
They are also one of the five most diverse vertebrate orders.

Skull

craniumcranialhuman skull
Hagfish do, however, possess a cranium.
The skull is a bony structure that forms the head in vertebrates.

Vertebra

vertebraeneural spineneural arch
The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, the lampreys, do.
In the vertebrate spinal column, each vertebra is an irregular bone with a complex structure composed of bone and some hyaline cartilage, the proportions of which vary according to the segment of the backbone and the species of vertebrate.

Vertebral column

spinespinal columnspinal
Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, at up to 33 m. Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns.
The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordates has been replaced by a segmented series of bone: vertebrae separated by intervertebral discs.

Craniate

Craniatacraniatespreoccupied
For this reason, the vertebrate subphylum is sometimes referred to as "Craniata" when discussing morphology.
Formerly distinct from vertebrates by excluding hagfish, molecular and anatomical research in the 21st century has led to the reinclusion of hagfish, making living craniates synonymous with living vertebrates.

Notochord

notocordembryonic notochord cells
All vertebrates are built along the basic chordate body plan: a stiff rod running through the length of the animal (vertebral column and/or notochord), with a hollow tube of nervous tissue (the spinal cord) above it and the gastrointestinal tract below.
In vertebrates the notochord becomes part of the vertebral column.

Chondrichthyes

cartilaginous fishchondrichthyanscartilaginous fishes
The bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven.
Chondrichthyes (from Greek χονδρ- chondr- 'cartilage', ἰχθύς ichthys 'fish') is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone.

Lamprey

lampreysPetromyzontiformesammocoetes
The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, the lampreys, do.
Taxonomists place lampreys and hagfish in the subphylum Vertebrata of the phylum Chordata, which also includes the invertebrate subphyla Tunicata (sea-squirts) and the fish-like Cephalochordata (lancelets or Amphioxus).

Body plan

bauplanBody formbodyplan
All vertebrates are built along the basic chordate body plan: a stiff rod running through the length of the animal (vertebral column and/or notochord), with a hollow tube of nervous tissue (the spinal cord) above it and the gastrointestinal tract below.
The history of the discovery of body plans can be seen as a movement from a worldview centred on the vertebrates, to seeing the vertebrates (or chordates) as one phylum's body plan among many.

Lung

lungspulmonaryright lung
These are reduced in adulthood, their function taken over by the gills proper in fishes and by lungs in most amphibians.
In mammals and most other vertebrates, two lungs are located near the backbone on either side of the heart.

Tail

caudalcaudal appendagevestigial tail
The remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut.
While tails are primarily a feature of vertebrates, some invertebrates including scorpions and springtails, as well as snails and slugs, have tail-like appendages that are sometimes referred to as tails.

Brain

brain functionmammalian braincerebral
The vertebrates are the only chordate group to exhibit cephalisation, the concentration of brain functions in the head.
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals.

Neural crest

neural crest cellsneural crest cellcrest
Of particular importance and unique to vertebrates is the presence of neural crest cells.
The emergence of neural crest was important in vertebrate evolution because many of its structural derivatives are defining features of the vertebrate clade.

Lancelet

amphioxusAmphioxiformeslancelets
A slight swelling of the anterior end of the nerve cord is found in the lancelet, a chordate, though it lacks the eyes and other complex sense organs comparable to those of vertebrates.
Zoologists are interested in them because they provide evolutionary insight into the origins of vertebrates.

Dorsal nerve cord

nerve corddorsaldorsal hollow nerve cord
The central nervous system of vertebrates is based on a hollow nerve cord running along the length of the animal.
The dorsal nerve cord is a unique feature to chordates, and it is mainly found in the Vertebrata chordate subphylum.

Shark

sharksSelachimorphaselachians
Shark eyes are similar to the eyes of other vertebrates, including similar lenses, corneas and retinas, though their eyesight is well adapted to the marine environment with the help of a tissue called tapetum lucidum.

Jaw

jawsgnathicjaw bone
While the more derived vertebrates lack gills, the gill arches form during fetal development, and form the basis of essential structures such as jaws, the thyroid gland, the larynx, the columella (corresponding to the stapes in mammals) and, in mammals, the malleus and incus.
In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw and a lower jaw.

Chordate

Chordatachordatesnerve cord
Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). The vertebrates are the only chordate group to exhibit cephalisation, the concentration of brain functions in the head.
Chordates are divided into three subphyla: Vertebrata (fish, amphibians, reptiles, birds, and mammals); Tunicata or Urochordata (sea squirts, salps); and Cephalochordata (which includes lancelets).

Cerebral hemisphere

hemispherecerebral hemisphereshemispheres
Vesicles of the forebrain are usually paired, giving rise to hemispheres like the cerebral hemispheres in mammals.
The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure.

Gill

gillsplastrongill filament
All basal vertebrates breathe with gills.
The gills of vertebrates typically develop in the walls of the pharynx, along a series of gill slits opening to the exterior.

Fish

fishesfinfishichthyofauna
In amphibians and some primitive bony fishes, the larvae bear external gills, branching off from the gill arches.
Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts.

Paedophryne amauensis

Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, at up to 33 m. Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns.
P. amauensis, attaining an average body size of only 7.7 mm, is 0.2 mm smaller than the previous record-holder as the world's smallest vertebrate, a species of cyprinid fish (Paedocypris progenetica; 7.9 mm) from Indonesia and a species of goby fish (Schindleria brevipinguis; 7.7 mm) from Australia.

Hindbrain

rhombencephalonhind-brainhind brain
The front end of the nerve tube is expanded by a thickening of the walls and expansion of the central canal of spinal cord into three primary brain vesicles: The prosencephalon (forebrain), mesencephalon (midbrain) and rhombencephalon (hindbrain), further differentiated in the various vertebrate groups.
The hindbrain or rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates.

Forebrain

prosencephalonfore-brainforebrains
The front end of the nerve tube is expanded by a thickening of the walls and expansion of the central canal of spinal cord into three primary brain vesicles: The prosencephalon (forebrain), mesencephalon (midbrain) and rhombencephalon (hindbrain), further differentiated in the various vertebrate groups.
In the anatomy of the brain of vertebrates, the forebrain or prosencephalon is the rostral (forward-most) portion of the brain.