Question

If you were building a cladogram based on rRNA analysis that was to include the chordate subphyla, which subphyla would be placed directly around the Craniata?

Answer 1

The sub-phyla that would be placed directly around the Craniata are Urochordata and the Cephalochordata.
Urochordates are small marine animals with larvae that swim freely and adults attach themselves to the ocean floor. They are commonly known as tunicates, differ from other chordate subphyla in that the adult form has no notochord, nerve cord,or tail. Cephalochordates or lancelets have notochord extends from near the tip of the tail to well into the anterior of the body. They do not have the braincase, or cranium, of a vertebrate, lancelets are often called acraniates.