Why are lamprey dogfish shark mudpuppy and cat the best choices to compare anatomical features of vertebrata?

Question

more specifically, in the subphylum vertebrata. i was just wondering why these are the best to compare and the distinct differences between them. thanks

Answer 1

My guess would be that they are in different Classes.

Answer 2

They are cheap and representative of different groups of vertebrates. Some courses add turtles and pigeons  or substitute rabbits for cats.