Well, as you write, the eastern NA fossil record is rather poorly known anyway.
Not into Africa and Madagascar. Theoretically everywhere else, but evidence (and time before the K-T extinction) is lacking.
You must have pretty good evidence to suggest that that scrap called Betasuchus is similar to anything particular. I've read it might have been an abelisaur.
This is clear anyway.
Its lack of clear American ancestry can also indicate that relevant fossils have not yet been found or that paleontologists have so far failed to recognize its close relatives as such (the former possibility is quite probable). And "primitive nature" says rather nothing. Plesiomorphies need not be explained, unlike apomorphies.
News to me... I only know Rhabdodon from there.
Another (unnamed, large) abelisaur has been found in France; Erectopus from the EK of France is/was regarded by some as an abelisaur, too, and there was Genusaurus.
All this supports occasional rare immigration from Africa to Europe -- nobody needs a land bridge for this.
Not in the least. You imply that there are no vertebrates on oceanic islands like Galápagos. Madagascar has been totally surrounded by sea since it ripped off of India. ("Ice Age land bridges" are impossible, the sea is far too deep there.)
Indeed, I haven't seen this anywhere else than in "Dinosaurs: A Global View".
The type and only specimen of Notoceratops is lost, so we still don't know whether it was a hadrosaur or a ceratopsian.
Who is this? Ref? :-|
Nonsense, as others have already pointed out.
1. Who still believes in a simple climatic change as the cause for the K-T mass extinction???
2. Do you try to explain the extinction of each genus separately? Good luck :-> !!! What about Hypselosaurus, Pyroraptor, Variraptor, Euronychodon, Pararhabdodon, Rhabdodon, ... which ones have I missed?
Defenders. The Great Battle about Euramerica. Sorry, evolution and extinction don't work like that.
As I wrote you (have you read it?), in the last few million years before the K-T, when the sea level sank, a new type of vegetation appeared in southwestern Europe, and hadrosaurs like Pararhabdodon seem to have replaced the titanosaurs. AND THIS FAUNA REMAINED THERE HAPPILY EVER AFTER till the meteorite struck a few million years later. How does this foreshadow extinction?