Taxonomy is fucked up. You start out at "This is how our animal friends are classified and how they're related to each other :)" and then you dip one inch below the surface and you get "There's definitely no such thing as a fish and there might be no such thing as a reptile"
iirc isnt the contention about what is and isnt a reptile based on if birds get considered reptiles, then turtles and snakes cant be?