The interrelationships between major living vertebrate, and even chordate, groups are now reasonably well resolved thanks to a large amount of generally congruent data derived from molecular sequences ...

Biologists have considered nearly every major taxon of animals as the key starting point for the evolution of vertebrates. We survey these ideas, many of which are no longer tenable in the light of ...

Hagfish represent an ancient lineage of boneless and jawless vertebrates. Among several curious behaviors they exhibit, solitary individuals in one dominant genus of hagfish (Eptatretus spp.) ...

Those of you who took high school biology may remember the lancelet, also known as the amphioxus. Its simplified body plan is notable for containing a number of features that it shares in common with ...