Differentiating Brontosaurus from Apatosaurus

[Ludodactylus]

My wife is prone to anxiety, and one of the most effective ways we've found to "get the hamster off the wheel" so to speak is for me to start telling her facts about dinosaurs. Her brain starts settling very quickly and she gets focused on my rambling narration so she can break the mental spiral that otherwise occurs.

Tonight we wound up on the topic of Apatosaurus and Brontosaurus, and the history and relationship between the two names. She had some follow-up questions that I couldn't immediately answer about the decision to resurrect Brontosaurus, and my own readings tonight after she fell asleep aren't making things clear for me.

The 2015 review of diplodocids that resurrected Brontosaurus as a valid genus mentions a variety of points of comparison that serve to differentiate the two, but I'm having trouble translating them into laypersons terms I can tell my wife tomorrow. It seems Apatosaurus had a wider neck likely held at a lower angle? And may have been more massive overall? Beyond that I'm not real clear on the differences between these two animals.

Would anyone be so kind as to give me a run-down of the differences, or point me to a layperson-friendly publication?

[crazy8wizard]

Brontosaurus fossils have been found spanning earlier in time than Apatosaurus. Around 156 million years, but Apatosaurus has been found starting 150 million years ago. The two do have a bit of overlap later in time as far as I know, so they coexisted.