An Earlier Alien Link to the Solar System, and the circumstantial evidence of the Ionian discovery thereof

The exact location of the Spatial Link between Earth's Solar System and Ionian Space is a closely guarded secret, which plays a role in the story of the Recontact, to be discussed elsewhere.

During the course of the approximately 16,000 years of human culture within Ionian Space, however, it gradually became clear to human scientists that the Ionians had contact with Old Earth that exceeded a single visit in the relatively recent past. This inference derived from evidence that there had been some surveillance and continuous contact with the original home world of the human species in the millennia that followed the original contact. This too, is an essential element of the story of the Recontact, and the details of the unfolding of this mystery are told elsewhere.

Although prior to the period of the Recontact, humans knew very little of Old Earth, and therefore had no basis to suspect the fact, it was eventually realized, post-Recontact, that there must have also been at least one other link in Solar System Space that connected to a location from which contact had been made with Earth in a much more remote past time than the initial Ionian contact. The evidence consisted mainly of the fact that there were species of prehistoric plants and animals on Zubos and other human worlds and habitatats of Ionian Space which certainly did not exist on Earth 16,000 years ago (along with many that did, but which had since become extinct on Earth). The assumption was that there had been at least one other alien visit to Earth, long before the Ionians discovered Earth, or even had become a spacefaring civilization on their own. 

It was generally understood, even before the Recontact, and despite the fact that the Ionians did not share this kind of information, that the Ionians were in contact with, or aware of, truly ancient alien civilizations with which they had come into contact or discovered as extinct civilizations while exploring Connected Space. An intriguing mystery presented itself from the evidence that one of these extremely ancient civilizations must have been discovered by means of the Link with the original home of humanity, Old Earth. Again, the evidence was purely circumstantial, but no other explanation presented itself. The assumption was that the civilization itself was either extinct or otherwise no longer in contact with Solar System space.

The actual evidence consisted of living small dinosaurs which had become extinct on earth over 65 million years earlier, but which continued to thrive on one or more of the human habitations and planets. There were also plants descended from cycads and ginkgos, as well as giant club mosses, extinct varieties of fishes and arthropods, ammonites, extinct mammalian and reptilian orders, and numerous other forms of life, which were either no longer extant on Earth long before the Ionian contact, or which belonged to branches of life forms that still survived, but which were, in the specific forms found, no longer present on Earth itself, nor had been for ages past. The assumption was that some other aliens had taken an interest in Earth much, much earlier, probably around the time of the extinction of the dinosaurs, and that these aliens had transported these life forms to one or more other worlds, reachable via sequential link from the Solar System. Further, it was inferrable that the Ionians had at some point visited this other world or worlds, and transported some of these life forms, not back to their original home, Old Earth, but to some of the human worlds of Ionian space.  

The inference that Earth was the connection between these ancient preserved life forms and modern Ionian Space was the only reasonable conclusion. The Ionian reticence to discuss the details of their discoveries and the extent of their "empire" in Connected Space, which approached and even transcended outright paranoia, left the human scientists who pondered these questions to conjecture, infer, and deduce what facts they could, without the confirmation or additional details that undoubtedly were well within the power of the Ionians to grant. From a human point of view, their invariable refusal to do so, or even to communicate on the subject at all, was beyond frustrating, but it had been a fact of life for so long that it just had to be accepted. It was, in fact, scientific investigators from Earth itself who found this entire subject so compelling that they sought to push for disclosure from the Ionians, but cooler and more experienced heads at places like the Institute for Urbonian Biology at Zortzipak, realized that this was a fool's errand: the Ionians would divulge nothing. If there was more to be learned of the "Old Ones," as they came to be known, who must have visited Earth tens of millions of years ago, it would have to be the result of human re-discovery, via the Solar System Link that must exist or have existed, if that were even possible. But where was it? How could it be found? All these things remained unknowns.