I remember reading the book in 3rd grade. The main characters were a team of large humanoid dinosaurs that were fighting against a similar team of humanoid dinosaurs led by a large alien who had a similar appearance to Shredder from Teenage Mutant Ninja Turtles.
One plot point I remember is the villainous team of dinosaurs stealing nuclear warheads from a US base somewhere in the Arctic. Another plot point involved the alien villain traveling back in time to the Cretaceous Period, fighting a T-Rex, then collecting some other dinosaurs to put in his ship (implied to be the future villainous team of dinosaurs he creates.)
The art style was similar to other comics coming out in the 2000s. I believe it released sometime in 2008 if I remember correctly. Fight sequences involved laser weapons and hand to hand combat, preventing a highly catastrophic event from happening such as a city being blown up, etc. There are humans in the story, mainly ones helping the main team of dinosaurs.