A Chimera Species is a hybrid of two or more distinct species. Alternatively, a chimera is a sophont who has been significantly altered through the inclusion of genetic material from one or more species (...not necessarily sophonts).
A Chimera is a hybrid of two or more distinct species, produced naturally or through Genetic engineering. In some cases the term is also erroneously used for a variant race, an intelligent species that has undergone significant genetic modification at a time after its parent species became part of the interstellar community. In all cases the result is a new, unique species.
Many laymen consider such species to be minor races, but since they have had no chance to invent jump drive on their own, but may be descended from races that did, they don't fit the usual definition of either.
These species may or may not rate their own taxonomic name. This often depends on political considerations, although sometimes there are sound practical reasons for an omission.