It appears to me that direct descendants of dinosaurs are chickens.

And so, i believe the weight of the largest dinosaurs was much less than the mammal equivalent. There is evidence that they had the lighter bone structure and muscle structure of birds.

But still, that is a lot of weight.

If you add to this the ideas of super-mega trees in our past (see the video There Are No Forests On Earth) where devils tower is actually a tree stump as well as the mesas in arizona. Then it looks like things were much larger back then. And was that because earth changed? A completely different atmosphere? Different earth size? Different gravity due to changes of electric potential?

These are all good questions to go into. However, it is really hard to tell, because the data was so mucked up by the smithsonian and their cohort of egotistical dinosaur bone seekers. Modern scientists who work with dinosaur bones are finding that most of the skeletons those jerks found were actually pieced together from all kinds of pieces. A frankenstein's monster.

So, most of the stuff like age, location, climate... has all been messed with.

And, there is a story of a couple of cowboys that shot and killed a pterodactyl. They strung it up across a barn and many people came to see it. There were pictures of it... but "top men" came and collected them.