Dryopidae, Billberg, 1820

Bilton, David T. & Shepard, William D., 2022, Rhithrops capensis gen. et sp. nov., a new aquatic dryopid beetle from the Western Cape of South Africa (Coleoptera: Dryopoidea: Dryopidae), Zootaxa 5195 (6), pp. 539-553 : 552

Revised key to South African Dryopidae genera

The key below is based on that of Nelson (2007), adapted to incorporate Rhithrops gen. nov. and Pedestrodryops Kodada, 2001 .

1 Almost entire dorsum and venter with long, fine, sparse erect sensillae; terrestrial, in plant litter away from water … Pedestrodryops Kodada, 2001

- Cuticular vestiture shorter and denser; aquatic taxa.......................................................... 2

2 Eyes conspicuously pubescent.......................................................................... 3

- Eyes not conspicuously pubescent, at most with scattered peg-like setae between facets............................. 4

3 First antennomere elongate; second antennomere large, transverse, more or less rectangular, distal border rounded......................................................................................... Ahaggaria Bollow, 1938

- First antennomere not elongate; second antennomere enlarged, ear-shaped, distal border angular...... Dryops Olivier, 1791

4 Antennae with 10 antennomeres; second antennomere enlarged, ear-shaped, covering most of rest of antennomeres; pronotum with sublateral furrows but no carinae..................................................... Rhithrops gen. nov.

- Antennae with fewer than 10 antennomeres; second antennomere smaller; pronotum with sublateral stepped carinae...... 5

5 Antennae with 9 antennomeres; sublateral pronotal carinae with lateral flange; prosternal process large, gradually narrowed apically; mesotibial cleaning fringe a dense tuft of golden setae; ovipositor with coxites dorsally serrate Strina Redtenbacher, 1867

- Antennae with 7 antennomeres; lateral margin of pronotum without lateral flange; prosternal process large, abruptly narrowed apically; mesotibial cleaning fringe not a dense tuft of golden setae; ovipositor with coxites not serrate dorsally........................................................................................... Rapnus Grouvelle, 1899