1. The primary type of the type species of a genus established by virtue of tautonymy.
2. The type of a genus whose species-group name is identical in spelling with the genus-group name.

Tautonymy is the possession by two or more distinct plants or animals of the same generic and specific names which are prohibited by the rules of scientific nomenclature; for example to refer to an animal as a "bison" and a plant identified as a "bison weed".

The type of a genus whose species-group name is identical in spelling with the genus-group name.