When using the evolutionary time frame we usually separate living organisms into the two categories that you mentioned, e.g. modern or prehistoric. As those who have acknowledged the biblical Flood as the major factor in the creation of the geologic column as well as the fossil record, we would not by apt to buy into the classic evolutionary argument concerning change over time.
Ardipithecus ramidus, or as we have come to know her Ardi, is supposed to represent the oldest fossilized specimen or the earliest of the so-called missing links in ape-to-man evolution. She is said to predate the discovery of other hominids, e.g. the australopithecines. These precursors to man, e.g. Lucy and her australopithecine relatives refer to the discoveries of the renowned Kenyan archeologists Louis and Mary Leakey.