Subfamily Bellamyinae Rohrbach, 1937

Identification key to genera Bakyietaia gen. nov., Taia, Angulyagra *, Sinotaia, Anulotaia, Filopaludina

1. Columellar lip recurved, forming callus covering umbilicus completely or partially ...................... 2

– Columellar lip simple, not recurved, umbilicus open ....................................................................... 3

2. Primary keels smooth, operculum with small nuclear region (around 1/4 to 1/5 of inner opercular region) with shiny grains or veins ........................ Bakyietaia Zhang, Yen & von Rintelen gen. nov.

– Keel absent, or with obvious spines or nodules on primary keel, inner opercular region completely or partly covered by a rough sandpaper-like layer .......................................... Taia Annandale, 1918

3. Umbilicus widely open, with a strong keel around, primary keels strong ....................................... 4

– Umbilicus narrowly open, without obvious keel around, primary keel weak or absent .................. 5

4. Shell large, ~ 35 mm in height, thin and fragile, operculum with growth lamellae on exterior surface and radial striae on interior surface, with large smooth nuclear region (around 1/3 of inner opercular region) ............................................................................................................ Angulyagra Rao, 1931

– Shell small to medium, always 20 to 30 mm in height, thick and solid, operculum with small nuclear region (around 1/5 of inner opercular region) with shiny grains or veins ..... Anulotaia Brandt, 1968

5. Operculum with small nuclear region with shiny grains or veins ...................... Sinotaia Haas, 1939

– Operculum with inner opercular region (including nuclear region) completely or partly covered by a rough sandpaper-like layer ...................................................................... Filopaludina Habe, 1964

*Only characters of the type species of Angulyagra have been included when building the key.