Lancelets and tunicates are types of which group?

• A. Invertebrate chordates
• B. Vertebrates
• C. Non-chordate invertebrates
• D. Craniates

Answer: (A)

Chordates share features such as a notochord, a dorsal nerve cord, pharyngeal slits, and a post-anal tail at some life stage. Lancelets and tunicates are examples of chordates that lack a backbone, making them invertebrate chordates. Lancelets (cephalochordates) keep a notochord throughout life and do not have a vertebral column. Tunicates (urochordates) appear very simple as adults, but their larval form exhibits the defining chordate features, including a notochord and dorsal nerve cord. Since they do not possess a vertebral column, they are not vertebrates or craniates.