Key to genera of tribe Figulini from China

[Modified from Huang & Chen 2017]

1 The outer margin of mandible with a strongly upturned dorsal appendage......................................... 2

– The outer margin of mandible without dorsal appendages...................................................... 3

2 Body slender in form; mandibles roughly symmetrical on both sides; elytra longer than the combined length of the head and pronotum; hindwing normally developed............................................... Nigidius MacLeay, 1819

– Body short and robust in form; mandibles strongly asymmetrical on both sides; elytra shorter than the combined length of the head and pronotum; hindwings distinctly atrophied..................... Geonigidius Xin, Gong, Zhong & Qi, gen. nov.

3 Body length usually more than 24 mm; scutellum not more than twice as long as wide. Pronotum with a pair of anterior lateral lobes, not smoothly joined with the lateral margins...................................... Nigidionus Kriesche, 1926

– Body length usually less than 22 mm; scutellum more than twice longer than wide. Pronotum at most with anterior part of lateral margins narrowly flattened, not forming lateral lobes................................................... 4

4 Punctures on elytra notably denser and larger everywhere, making grooves scarcely recognizable. Profemur shorter. Basal piece of male genitalia more than 2.5 times longer than wide, with ventral caudal plate not extending so far to hide the median lobe.............................................................................. Cardanus Westwood, 1834

– Punctures on elytra thinner at the spaces between the grooves, making the grooves readily recognizable from the smooth spaces. Profemur longer. Basal piece of male genitalia at most 2.5 times longer than wide, with ventral caudal plate extending so far to hide the median lobe................................................................. Figulus MacLeay, 1819