@zephyr1 tasked me with this thread. I take my paleontology fairly seriously, but feel free to drop in some ridiculousness as well.
This thread will only deal with non-avian dinosaurs. Macaws, magpies and other creatures based on extant avian dinosaur species aren’t included.
So, are you sitting comfortably? Then I’ll begin.
Stegosaurian
This animal is clearly based on the Jurassic Classic Stegosaurus. Stegosaurus was the largest of the stegosaurs and its name means ‘roof lizard’ because the plates were originally imagined to lie across it’s back like armour.
The true use of the plates isn’t known, however defence is actually an unlikely reason because they were not connected to the body by any robust means. Increasingly, appendages on dinosaurs are thought to be for attracting a mate, such as the large human that @kayo wears as a head crest.
Myth busting: Stegosaurus did not have three brains as listed in some old books.
Dromosaurus
This creature is named after the Dromaeosaurus, a small theropod thought to be an ancestor of more derived raptors such as Velociraptor and Deinonychus.
That being said, the art shows the animal without a sickle claw common to this family. The animal depicted is more closely based on compsognathus, a tiny chicken sized predator which featured in Jurassic Park 2.
Myth busting: the Velociraptor shown in Jurassic Park are actually Deinonychus. The author, Michael Crichton stated that he just thought the name was cool.
Carnosaurian
It’s a T-Rex… right? Wrong! This animal has three fingers and Tyrannosaurus only has two. But it does have the robust U-shaped jaw of the tyrannosaur, unlike the more laterally compressed, narrow bite of earlier Theropods like Allosaurus.
So, perhaps it’s a more basal animal such as Dasplatosaurus?
Myth busting: the idea that Tryrannosaurus hunted on sight alone is absolute bunkum - the animal had the largest olfactory bulb of any known animal, demonstrating that smell was an important part of it’s arsenal.
Alpha Carnosaurian
Another very robust looking derived theropod, this creature appears to have a very sturdy back and hindquarters.
A dinosaur that matches this profile could be Acrocanthosaurus, a predator with large neural spines thought to support a fatty hump along it’s spine. The purpose of this hump is unknown but could be an energy store or, again, used to attract the opposite gender.
For anyone interested in further reading, I commend to you the superb Prehistoric Wildlife it’s not the most glamorous website, but it’s incredibly thorough.
Pterosaurian
N.B. Pterosaurs are not dinosaurs. Or even related to them. They are purely contemporaneous.
The creature depicted above is an amalgamation of both the basal features of ramphoryncids such as tails and teeth, and the more derived features of the later pterodactylus family such as the headcrest found in the popular pteranodon.
There is speculation and practical experimentation around the mechanics of Pterosaur flight with current thinking being that they would sit back on their haunches and then launch themselves forward without a run up, probably from cliff tops.
Debate is most fierce around the feeding practices of the very largest flying creatures Quetzalcoatlus and Hatzegopteryx. These mind bogglingly huge animals, as tall as giraffe, may have eaten like storks, however there is evidence also that they were perfectly capable of flight.
