Sebaceanoid refers to any unnamed notable genetic variant or subspecies on the Sebacean physiological type. This is to say, any species that might have the initial appearances of a Sebacean, but upon closer examination bears remarkable differences.
Such examples are the Sykarans, seen in Season 1 in the episode, (1.6 "Thank God It's Friday... Again"). Aeryn Sun referred to the species as "a distant cousin, at best." Other examples are members of the Clansmen on the Royal cemetery planet. They would appear to be Sebacean in all respects... except that during pregnancy the distended female abdomen becomes translucent, allowing the developing fetus to be seen within. Until Aeryn Sun became pregnant with D'Argo Sun-Crichton that it could be verified that Sebacean women do not experience the same phenomenon.
An analogous real-life example would be the relationship of the Neanderthal subspecies (Homo sapiens neanderthalensis) to the Anatomical Modern Human (AMH) subspecies (Homo sapiens sapiens) of the Human (Homo sapiens) line.