 At the species level, subjective synonyms are common because of an unexpectedly large range of variation in a species, or simple ignorance about an earlier description, may lead a biologist to describe a newly discovered specimen as a new species.A common reason for objective synonyms at this level is the creation of a replacement name.It is possible for a junior synonym to be given precedence over a senior synonym, primarily when the senior name has not been used since 1899, and the junior name is in common use.