Classes of Vertebrates

To the tune of "Eye of the Tiger" by Survivor

Agnatha have no jaw
Include the hagfish and lamprey
Jawed vertebrates are Gnathostomata
This group can further subdivide

Into the Chondrichthyans
With skeletons of cartilage
And the group known as Osteichthyans
With a skeleton of bones inside

This group can be further split up into
Ray finned fishes — Actinopterygii
The Teleosts are a member of this group
Everyone else has lobe finned limbs, Sarcopterygii

This group consists of
Actinistia and Dipnoid
And the Tetrapoda
Which are terrestrial adults

This further splits into the Amphibians
Which must develop in water
And Amniota which develop on land
With the protection of their amnion

Two groups of Amniota
The Sauropsids and Synapsids
Sauropsids are the Reptilia
Turtles, Lepidosaurs, and Archosaurs

Mammals are the only extant synapsid group
Include Monotremes, Marsupials, and Placentals
Synapomorphic traits of this clade in include
Mammary glands, and hair, and the synapsid skull