Within the large group of beetles, the stag beetles form a separate family of about 1200 species worldwide and about 41 species in Europe. Al these stag beetles have the same type of antenna but largely differ in size, color and form. The species that are most similar to the European stag beetle (Lucanus cervus) are grouped in the genus Lucanus. This genus includes four other species in Europe, all of them to be found in the Mediterranean region.
Furthermore, some other beetles might resemble a female stag beetle at first sight but can be easily recognised based on several characteristics.
A photo overview of the European stag beetle can be found here.