"sibling species." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/sibling-species>.
sibling species. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/sibling-species
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.