In both Spec and our home timestream, primates evolved at the cusp of the Cretaceous-Paleogene boundary. Fragmentary evidence from Home-Earth (none has yet been found in Spec) suggests simian precursors in the latest Cretaceous, but these fossils (called Purgatorius) are only tentatively assigned to Primates. These climbers may, therefore, have evolved after the end of the Cretaceous, in which case their presence on Spec is yet another example of parallelism and the primate-like creatures of Spec should be properly called p-Primates. However, since even the exhaustively analyzed primate fossil record of Home Earth remains unclear on the matter, most researchers are content to group both Spec and our own primate species into a single clade.