Boom! There goes the “exquisitely documented” evolution of turtles. Sorry, Professor Dave.
Paleontology sometimes seems like a kind of imaginative Rorschach test with the flattened fauna of roadkill.
Rapid eye movement may indicate neural activity, but dreaming for me implies a conscious awareness of the dream state, which I consider as unlikely in spiders.
We have tended to assume that intelligence rose with the development of a spinal cord and brain (vertebrates), and warmbloodedness (mammals and birds).
Sometimes you don’t need a rigorous logical, scientific, or mathematical demonstration to reveal evidence of design in nature.