I've had this idea for a while now. The Earth is dying. What once was a vibrant world full of life is now an overpopulated, overpolluted rock where the only oxygen comes from rebreathers and massive atmospheric processors. There are two hopes for Terrans: save up enough money to buy a ticket to Himmel, a self-sustaining space station in orbit around the moon... or enter the Rift.

Nobody knows how it came to be, or why it only opened now, but the Rift is a wormhole leading to a parallel dimension. In comparison to Terra Prime, this Earth is younger. But its flora and fauna have evolved differently. Sixty-five million years ago, in Terra Prime, an asteroid hit the Earth and began a series of disasters that caused a mass extinction. Twenty million years ago, the same asteroid missed Terra Secundo, and dinosaurs continued to evolve. While the ride to Terra Secundo is free, it's not guaranteed that you'll survive outside the city walls.

So, the RP would also have a player-created field guide, in which patrons could submit new species that could possibly become RP canon. I have a few ideas already:

Neocarnotaurus- Descended from Abelisaurids, Neocarnotaurus- are the T. rexes of South America. In the twenty million years since its namesake sent extinct, Abelisaurid arms have become little more than large claws almost parallel to the body, used by males during courtship.
Oliceratops- The very largest of the horned dinosaurs, Oliceratops behave in much the same fashion as elephants, and even mourn to a small degree if they find bones of their species. A small population has been tamed, and is undergoing domestication.
Necrosaurus- A rather unique herbivore descended from Ankylosaurids. Rather than stand and fight, Necrosaurs will play dead, rolling over on their backs and secreting a foul-smelling liquid that deters all but the hungriest of carnivores.
Cetosaurus- A true marine dinosaur that is thought to have descended from Spinosaurus. The largest individuals are as large a s modern whales, and have been known to kill fishermen who go too far out.
Dracosaurs- Sometime in the past twenty million years the pterosaurs have gone extinct. Before birds could grow much larger to fill the many niches pterosaurs encompassed, a branch of dinosaurs evolved from animals like Yi. Dracosaurs range in size from a parrot to a glider plane, and are known to be territorial.
Novadon- Novadon are small, nocturnal omnivores that evolved from Troodon. Some have been captured and trained as "watch dogs". Since their skills have more room for their brains than anchoring muscles, their jaws are quite weak. However they make up for this with venom. Their intelligence has been studied, and have been found to be as intelligent as chimpanzees.
Neoraptors- Descended from species like Utahraptor and Achillobator, Neoraptors are man-sized predators of remarkable intelligence. Studies indicate they have a primitive language, and can practice deception unlike any other species, save humans. Attacks on humans in their territory have been avoided by offering "appeasement gifts" of food.