Step 1: In biological nomenclature, each organism is given a binomial name consisting of a genus name and a species name.
Step 2: When the genus name and species name are exactly the same, such a name is called a tautonym.
Step 3: Examples of tautonyms include:
\textit{Bison bison}
\textit{Naja naja}
Step 4: Tautonyms are permitted in zoological nomenclature but not in botanical nomenclature.