Atomaria rubida Reitter, 1875

This species is widespread though apparently very local and sporadic across much of Europe from Portugal to the Black Sea and extending north to the UK and some of the Baltic countries but not in Fennoscandia. The modern distribution is likely be more extensive than this as Atomaria species tend to be rather neglected e.g. it is known in Finland from a single old record and is now considered to be very rare or possibly extinct, and there is a single Dutch example which for a long time was misidentified as A. gibbula. In the UK it is widespread and locally common across southern and central England and Wales and very local and generally scarce further north into Western Scotland including some of the Western Isles. Adults are active from March until August, peaking in abundance during May and again in July and they probably overwinter as specimens have been recorded into December. They are usually associated with herbivore dung, especially that of horse, cow and sheep, especially on grazing pasture and then often near to woodland.  Nothing is known of the biology but larvae probably consume fungi (as is typical of the family) developing on dung. Adults may be sampled sieving dung or by using dung-baited traps, and they sometimes occur in flood refuse and flight-interception traps.

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1.4-1.7mm. Elongate-oval and discontinuous in outline, body finely pubescent and shiny black or dark red, often with the head, elytral humeri and apex paler, antennae red, legs brown. Head smoothly convex and very finely punctured between convex and slightly protruding eyes, temples usually retracted into the thorax and only very narrowly visible, and frons produced beyond the antennal insertions. Antennae separated by about the length of the basal segment, 11-segmented; the basal segment at most only a little longer than the second segment and distinctly clubbed with segments 9 and 10 transverse. Pronotum transverse, broadest about the middle and parallel-sided or only slightly narrowed to perpendicular or slightly obtuse posterior angles, and strongly narrowed to an almost straight apical margin. Surface smooth and lacking microsculpture towards the base, finely but not densely punctured throughout and with stronger punctures within a transverse basal impression, pubescence directed forwards in the basal half and along the midline to the apical margin, in the apical half directed from the midline towards the lateral margins. Scutellum quadrangular and widely transverse. Elytra broadest at the middle and smoothly curved from sloping shoulders to a continuous apical margin that covers the abdomen, surface finely and randomly punctured throughout.