Is the frilled shark a vertebrate?

Yes, the frilled shark (Chlamydoselachus anguineus) is a vertebrate. It belongs to the class Chondrichthyes, which includes cartilaginous fish. Vertebrates are animals with a backbone, and the frilled shark has a cartilaginous backbone, making it a vertebrate.

Where does the oxygen come from that aquatic organisms need?
Why aquatic animals cannot breathe when they are on land?