∞ generated and posted on 2016.11.06 ∞
Animals that possess backbones.
This includes fish, amphibians, reptiles, birds, and mammals. While most vertebrates possess jaws, in fact jawed vertebrates are descendants of jawless ancestors, fish called agnathans, which are exemplified among extant fish by the blood-sucking lampreys. Vertebrata is a subphylum of phylum Chordata.
Like members of phylum Echinodermata, all chordates are triploblastic, coelomates, and deuterostomes. Other subphyla of phylum Chordata are subphylum Urochordata (the tunicates) and Cephalochordata (the lancelets). Thus, vertebrates are not alone among chordates, but are by far the most successful members of that/our phylum.
Note that it is the hagfish which arguably are vertebrates but which lack backbones as well as jaws.