Arthropleura roamed the late carbonifrus on a global scale. The largest insect to ever exist on the planet it was longer than a man at about 2 meters long. When standing up it could look a man in the eyes. It's only enemies were the local amphibians in the area. I can't remember their names but water was dangerous for arthropleura or any animal really. At this time the first reptiles of the carbonifrus 300 million years ago lived alongside this giant monster of a bug.
While eurypterids were aquatic and while being the first to go on land, some eurypterids during the carbonifrus period decided to take control of the land. They evolved legs and moved on land. As this happened insects and amphibians also lived on land.
Meganeura was the size of an eagle and is the size as your hands. The high oxygen levels allowed the insects to grow to these immense sizes seen in the carbonifrus period. The oxygen levels were up to instead of today's oxygen levels in the air.
Eustreptospondylus males when fighting for food ended in either death or near death. Food is kind of scarce on these islands they travel to. If food is scarce, fighting is necessary to survive. It went extinct because of the disappearing of the islands. Sea levels were rising and the islands were disappearing. It could not find anymore food and simply went extinct.
Argentinosaurus nests were always being eaten by for example venoraptor. With giganotosaurus it was able to grab little pieces of of the sauropods for it's food. Keeping the sauropods alive was vital for their food.
Gastonia was a lighter weight ankylosaur living in a very dangerous time. Gastonia was very successful. A spiked whip tail. With this gastonia was hard to kill. One swipe from the tail is enough to make the animal lose lots of it's blood.