1. Any of two or more related species that are morphologically nearly identical but are incapable of producing fertile hybrids. Sibling species can only be identified by genetic, biochemical, behavioral, or ecological factors, and are thought to have become divergent very recently.
2. Sibling species are pairs or groups of closely related species which are reproductively isolated but morphologically identical or nearly so.
Created: 2019-07-04 15:33:19 CDT (-0400)
Last modified: 2019-08-24 12:13:30 CDT (-0400)