Atomaria, Stephens, 1829

Lyubarsky, Georgy Yu. & Bukejs, Andris, 2022, TwonewfossilspeciesofthegenusAtomariaStephens (Coleoptera: Cryptophagidae) from Eocene European amber with a key to species described from fossil resins, Zootaxa 5188 (3), pp. 283-289 : 288

A key to extinct Eocene species of Atomaria

1. Body size smaller than 1.5 mm .......................................................................... 2

- Body size larger than 1.5 mm ........................................................................... 4

2. Body size 1.0– 1.2 mm. Antennomere 3 short, subquadrate, as long as wide, much shorter than antennomere 2. Pronotal disc convex.............................................................................................. 3

- Body size 1.35 mm. Antennomere 3 elongated, 1.5 times as long as wide, slightly shorter than antennomere 2. Antennomere 5 conical, elongated, 1.5× as long as wide. Pronotal disc flat. Lateral side borders of pronotum visible from above only in basal half of its length. Bitterfeld amber......................................... A. saxonica Lyubarsky et Perkovsky

3. Lateral side borders of pronotum visible from above along entire its length. Pronotum not narrowed toward base. Pronotum maximum width before the middle of its length. Antennomere 5 conical, elongated, 1.5× as long as wide. Body size 1.0 mm. Baltic amber............................................................ A. groehni Perkovsky et Lyubarsky

- Lateral side borders of pronotum visible from above only in basal half of its length. Pronotum narrowed toward base. Pronotum maximum width in the middle of its length. Antennomere 5 conical, nearly as long as wide, 1.1× as long as wide. Body size 1.19 mm. Rovno amber............................................................... A. perkovskyi sp. nov.

4. Pronotal disc convex.Antennomere 3 about 2× as long as wide.Antennomeres 9 and 10 strongly transverse. Pronotum maximum width nearly in the middle of its length. Base of pronotum with shallow depression. Body size 1.54 mm. Baltic amber......................................................................................... A. alekseevi sp. nov

- Pronotal disc flat. Antennomere 3 about 1.5× as long as wide. Antennomere 10 subquadrate, nearly as long as wide. Pronotum maximum width much behind the middle of its length. Base of pronotum without depression. Body size 1.65 mm. Baltic amber.............................................................. A. gedanicola Lyubarsky et Perkovsky