Longitarsus nigerrimus is a beetle (order Coleoptera) that belongs to the very large and world-wide family Chrysomelidae - the leaf-beetles.

Within this family it belongs to the Alticinae - flea-beetles.

In the UK alone, there are about 4,000 species of Coleoptera, of which about 250 are in the family Chrysomelidae and 41 in the genus Longitarsus.