Question

Which of the following jawless fish lays eggs in fresh water and its ammocoetes larvae after metamorphosis return to the ocean?

• A. Petromyzon
• B. Eptatretus
• C. Myxine
• D. Neomyxine

Answer 1

The correct option is A Petromyzon

Agnatha is a superclass of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present and extinct species for example Petromyzon. Petromyzon is a parasitic lamprey found in the northern Atlantic ocean along shores of Antartica and North America, in the western Mediterranean sea and in the shores of the Great lakes. It is brown, gray, or black on its back and white or gray on the underside and can grow up to 90 cm long.

After 1 year of hematophagous feeding, lampreys return to the river to spawn and die, one year and a half after the completion of metamorphosis.

So, the correct answer is option A.