I just recently finished a big Christmas piece and plan on posting it on Christmas Eve. In the mean time, I just finished some sketches I started in the previous month. They actually tie in with the Gladius story idea and it's major premise of other timelines merging into one. One of those timelines is one where the astroid impact that wiped out non-avian dinosaurs didn't happen. Here are some concepts based on a bit of research I was able to do plus some speculation.
Tyrannosaurus and titanosaurs (the top two dinosaurs), actually wouldn't change all that much as they were apparently really good at what they did (getting big). The biggest physical change would be reaching the absolute limits to their physical biology as the inland seas of the late Cretaceous period recede and continents like the Americas connect, allowing more room to expand. Behaviorally, I imagine the Tyrannosaurs to evolve more complex social behavior. There was already evidence social behavior and scans of their brain cavities indicated them having more intelligence than previously thought. Though they would never evolve true sapience (that was never a trend in dinosaur evolution), they could become better a coordinating family groups to achieve more successful hunts. They could even have a caste system based on age dedicated to hunting prey of different sizes so none of them go hungry. The most radical possibility is each family pack having it's own herd of herbivores that it monitors, guides, and protects from other predators so they can selectively feed on them themselves.
The ceratopsian is leaning on the speculative side a bit. There is evidence of smaller members this group possessing quills that run along their back and tails so it wouldn't be unimaginable that larger ceratopsians would have these as well. In the case of the evolved ceratopsian, I imaging it evolving more defenses as their predators become more powerful and cleaver. The aforementioned quills become more rigid like those of a porcupine and provide some defense from behind. The heads, of course, are formidable shields adorned with spikes and razor sharp beaks.
Pterosaurs were also reaching their peak in size, with the best know examples being Quetzalcoatlus and Hatzegopteryx. As a group they were very diverse and could continue being diverse even with the emergence of birds. The largest ones would continue being stork like predators but with slightly longer wings to traverse the entire globe and not be bound to any one continent.
The toorodontids are often cited to be the most intelligent dinosaurs having the largest brain-to-body ratio. In reality, their intelligence may have been more comparable to modern day flightless birds and as mentioned before intelligence never seemed to be a priority for dinosaurs. That said, evolved troodontids could develop intelligence similar to modern day corvids with anatomy more resembling modern day birds. They would still retain features like longer tails a toothed beaks as they don't need to fly* as well as their clawed fingers which in addition to their beaks and feet could be useful in primitive tool use.
I hope to expand on these more in the future, particularly the evolved tyrannosaurs and their caste structure.
As always, comments and critiques are welcome.
