Horse
Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus".
Erica
A number of increasingly detailed phylogenetic hypotheses for "Erica" have been published based on nuclear ribosomal and plastid DNA sequences. The closest relatives of "Erica" are "Daboecia" (one or two species) and "Calluna" (monospecific), representing the oldest surviving lineages of a, by inference, ancestrally Palearctic tribe Ericeae. The small number of European "Erica" species represent the oldest lineages of the genus, within which a single, order-of-magnitude more species-rich, African clade is nested. Within the African clade, Cape and Madagascan/Mascarene species respectively represent monophyletic groups.