Argis IV is old, older than Earth for certain. But for the longest time, researchers were unsure at exactly how old the planet was. Until a diving expedition in the Thusian Sea turned up rocks that when studied, revealed an age of nearly 5 billion years. This would indicate that Argis IV is even older than that. This was an astounding scientific find and it would help identify creatures in the fossil record all across Argis IV.

The oldest group of animals on Argis IV are the Coral Trees (Order Mutarecutisae). Uncomplicated lifeforms, they feed passively on the Aeroplankton just as they have for nearly a billion years. Their success lies in their simplicity and adaptability, as they can adapt to any situation very quickly in relativity to other creatures. They evolved from small mobile filter feeding animals in the oceans of Argis IV. Scientists are still baffled as to how they became terrestial. Many beleive they became stationary while still aquatic. As they evolved their trademark shell, the Coral Trees became protected from the heat and air of the surface. At first they were only found in coastal areas, but as millenia dragged on they slowly began to conquer the soil of Argis IV. The Aeroplankton they feed upon today had not yet evolved, so they had no reason to possess the fantastic shapes and heights they reach today. They collected minerals and nutrients from the soil itself, with a portion of their bodies sticking out of the ground for air. These subterranean forms are now extinct, out competed by photosynthids and the False-Trees.



For the longest time, the Coral Trees were the only forms of terrestrial life on Argis IV. For a period of nearly two million years it was nothing but Coral Trees as far as the eye could see. A few million years after the colonization of land by Mutarecutisae, there was another mass exodus from the sea. The small organisms of the waters almost seemed to burst into the terrestrial fossil record. Some specimens were preserved well enough that paleontologists were able to identify that these Aeroplankton were indeed the ancestors of those that are alive today. Further study revealed that these Aeroplankton had primitive, but fully developed air sacs. This has lead researchers to believe that Aeroplankton had originally evolved the air sacs to move more freely between the oceanic currents, intaking and ejecting water to sink and float. This ability probably helped with food collection and evading predation by the many planktivores. Some species eventually became able to intake and eject air as well, and became inhabitants of the skies of Argis IV. Over the course of their evolution the Aeroplankton were able to construct their own means of flotation, Helium. Of course, the Aeroplankton were unable to keep out of the reach of predators forever.