The Phylum Chordata is most likely the phylum most familiar to many people because within it are humans and other vertebrates, including of course Dendrobates azureus. To be technical and precise, there are five specific characteristics which all chordates exhibit throughout at least one point in their lifetime. These include: pharyngeal slits, a dorsal nerve cord, a notochord, a post-anal tail, and an endostyle. Pharyngeal slits are sometimes presented as gills in particular organisms but in animals which do not use gills these slits are gaps or openings which lead from the interior of the throat to the exterior of the area of the neck. A dorsal nerve cord is a cluster of nerves and nerve fibers which line the dorsal (or back) side. A notochord is a structure made of cartilage which follows underneath and supports the nerve cord. A post-anal tail is seen in many embryonic forms of the chordates and is a small protrusion of the body located above the anus of an organism.

Phylum (Chordata)