The reason I didn't include more theropods is just because of the space limitation. There was barely enough room for the three I included unless I made the boxes wider, in which case all the other boxes would have had a lot more empty space in them. (Unless I included more dinosaurs in every
group, which would have required a lot more work from Emily.)
Making the images for chart already involved more work from her than she really should have had time for, so she wasn't interested in illustrating things that aren't dinosaurs for it. There are a lot of other things we could've included on it, but we had to draw the line somewhere.
She and I discussed back and forth for quite a while about whether to include prosauropods or not. I was initially intending to leave them out because I assumed the group was obsolete, but she pointed out that Google scholar shows 114 results
since the beginning of 2013, so it can't be completely obsolete yet. The more relevant factor is that there isn't any other group within Sauropodomorpha that can include Massospondylus
. (Unless you think they're all plateosaurids, in which case Prosauropoda is just another name for Plateosauridae.) I'd like people looking at the chart to be able to understand that dinosaurs like these belong inside Sauropodomorpha, but outside Sauropoda.