|Named By:||T. D. A. Cockerell in 1906|
|Time Period:||Late Eocene|
|Location:||USA, Colorado - Florissant Formation|
|Size:||9.5 millimetres long|
|Fossil(s):||Partial remains of a female|
|Classification:||| Arthropoda | Insecta | Hymenoptera | Stephanidae ||
Protostephanus is an extinct genus of crown wasp in the Hymenoptera family Stephanidae known from an Eocene fossil found in the United States of America. The genus contains a single described species, Protostephanus ashmeadi placed in the stephanid subfamily Stephaninae.