Question

Differentiate between Agatha and Gnathostomata.

Answer 1

Hint: Agatha belongs to phylum chordata and group Vertebrata. It constitutes a superclass of fishes without jaws. The Cyclostomes (existing species) as well as conodonts and ostracoderms (extinct species) are included in subphylum Agatha. Another subphyla known as gnathostomata is sister to Agatha.

Complete answer:
Agatha and gnathostomata are the subphylum which belongs to kingdom Animalia. Cyclostomata class comprises Agatha division. It includes Hagfishes and Lampreys. Lampreys consist of teeth but jaws are absent. They are vertebrates with sucking mouths. It consists of a single nostril. Gnathostomata consists of sharks, rays and bony fishes. Cyclostomata as the name suggests, cyclos means “circular” and stoma means “mouth”. This means that individuals of this group have circular mouths.

Agatha	Gnathostomata
Their mouths lack jaws.	Jaws are present in their mouth.
It comprises most of the primitive craniates.	It comprises the advanced vertebrates.
Exoskeleton and appendages are absent in them.	Paired appendages (fins and limbs are present).
It includes cold-blooded animals.	These include both cold-blooded as well as warm-blooded animals.
Notochord is present throughout life.	In the embryonic stage, the notochord is present while in adults it is replaced by the vertebral column.

Note: Group Craniata consists of both Agatha and Gnathostomata. As the name suggests, cranium, commonly known as the brain box, has its role in protecting the brain. It comprises two sub phyla namely, Agatha and Gnathostomata.