A species name is usually made up of its genus followed by its species, like Homo sapiens. A tautonym is a species name in which the genus and species is the same, like Rattus rattus. To the casual reader, a tautonym implies that this is the first one discovered in a new genus, or else the most common species in that genus. That may or may not be true. When variations of a species are discovered, another name can be appended to designate the subspecies. If that subspecies name is the same as the other two names, you get a triple tautonym, like Bison bison bison. There are more triple tautonyms than you realized. Wikipedia has a list of 21, which may be expanded when others are submitted. The list is likely to lead you down a rabbit hole of looking for these subspecies, some of which have naming controversies, plus the list of "people with reduplicated names." -via Nag on the Lake
(Image credit: Jack Dykinga)
