Key to Pyrgoma species

1. Tergum with extended depressor muscle crests.............................................................. 2 – Tergum without extended depressor muscle crests........................................................... 3 2. Scutum with rostral tooth......................................................................... P. sinica – Scutum without rostral tooth................................................................... P. projectum 3. External furrow of tergum open......................................................................... 4 – External furrow of tergum closed at mid-point of tergum...................................................... 5 4. Tergum with narrow spur; spur of tergum width 1/10 as wide as height................................ P. cancellatum – Tergum with wide spur; spur of tergum width 1/5 as wide as height......................................... P. kuri 5. Tergum with narrow spur; spur of tergum width 1/9 as wide as height................................... P. japonica – Tergum with wide spur; spur of tergum width 1/5.5 as wide as height.......................... P. spurtruncata sp. nov.