In taxonomy, a segregate, or a segregate taxon is created when a taxon is split off from another taxon. This other taxon will be better known, usually bigger, and will continue to exist, even after the segregate taxon has been split off. A segregate will be either new or ephemeral: there is a tendency for taxonomists to disagree on segregates, and later workers often reunite a segregate with the 'mother' taxon. Wikipedia