Key to species of Silvanidae known from Eocene East European amber

1. Antenna long, extending nearly to middle of elytra or beyond; antennomere 1 large, at least 2× as long as wide; elytra distinctly wider than pronotum................................................................................... 2

- Antenna shorter, not extending to middle of elytra; antennomere 1 less than twice as long as wide; elytra slightly or not wider than pronotum........................................................................................ 3

2. Antenna 1.4× as long as body; antennomere 1 very long, about as long as antennomeres 1–3 combined; pronotum with undulating sides; body length 6.2 mm; Baltic amber..................................... Dendrobrontes popovi Kirejtshuk

- Antenna 0.5× as long as body; antennomere 1 about as long as antennomeres 1–2 combined; pronotum with five denticles on lateral side; body length 3.35 mm; Baltic amber................................... “ Airaphilus ” denticollis Ermisch

3. Antenna moderately long, extending to anterior one-fifth of elytra; antenna gradually thickened towards apex, without distinct club; pronotum with 12 small, sharp, regular, setiferous denticles on each lateral side; tarsomere 3 strongly lobed ventrally; body length 4.0– 4.5 mm. Baltic amber........................ Airaphilus simulacrum Alekseev, Bukejs & McKellar

- Antenna short, not extending to elytra; antennae with distinct club; pronotal denticles absent or differing in form and number; tarsomere 3 simple, neither lobed nor incrassate............................................................. 4

4. Pronotum with six denticles on each lateral side............................................................. 5

- Pronotum without regular denticles laterally................................................................ 6

5. Pronotum with three dorsal longitudinal ridges (two lateral and one medial one); each elytron with four entire carinae formed by raised interstriae 3, 5, 7, and 9; antennomeres 4–5 transverse; body length 2.5–2.7 mm; Baltic amber............................................................................................ Mistran ot Alekseev & Bukejs

- Pronotum without ridges or impressions; each elytron with two lateral carinae formed by raised interstriae 7 and 9; antennomeres 4–5 elongate; body length 4.1 mm; Rovno amber......................... Austronausibius aenigmatista sp. nov.

6. Pronotum with sharp denticle at posterior angle, finely and sparsely punctate; temples present; body length 2.3 mm; Baltic amber............................................ Cathartosilvanus siteiterralevis Alekseev, Bukejs & McKellar

- Pronotum without denticle at posterior angle, deeply and densely punctate; temples absent........................... 7

7. Pronotal lateral sides finely crenulate; anterolateral denticle distinct; pronotum as long as wide; elytral intervals partially convex; eyes without pubescence; body length 2.2 mm; Rovno amber....... Cathartosilvanus perkovskyi Alekseev & Bukejs

- Pronotal lateral sides slightly uneven; anterior pronotal angles rounded, without distinct denticle; pronotum slightly longer than wide; elytral intervals flat; eyes pubescent; body length 3.5 mm; Baltic amber....................................................................................................... Cathartosilvanus necromanticus Alekseev