Jawless Fish: Petromyzon and Myxine — NEET Biology

NTA tests your ability to classify jawless fish (agnathans) and identify their key characteristics, particularly Petromyzon (lamprey) and Myxine (hagfish). Students often confuse these primitive vertebrates with other fish groups, mistaking them for cartilaginous or bony fish, or failing to recall their distinctive features like the circular mouth, absence of jaws, and notochord instead of a true vertebral column. Remember: Petromyzon and Myxine are cyclostomes—the most primitive living vertebrates without paired fins or jaws. Focus on their unique adaptations like the sucker-like mouth for parasitic feeding (lamprey) to secure full marks on classification questions.