Euconnus fimetarius (Chaudoir, 1845)
This infrequently-recorded species has a mostly central European distribution from France to western Russia, extending north to the UK and southern Sweden and Finland, and south to Italy and the Balkan Peninsula. Here there are scattered records from southeast England and the Midlands, South Hampshire, South Wales and Anglesey but like most species of the subfamily it is likely to be under-recorded. Adults occur year-round, peaking from April to June and again during September and October, they inhabit decomposing vegetation in a wide range of situations including compost, moss and litter, they have also been recorded from decaying wood and sieved from material taken from a wood and nest. Our only Watford record was a single specimen extracted from a reed litter sample taken beside the river Gade during July 2014. Adults overwinter under leaf-litter or in the soil and are known to feed on various hard-bodies oribatid mites.
Adults are tiny, 1.4-1.6mm but very distinctive due to the form of the body and antennae. Entirely shiny black with brown appendages, body sparsely and very finely punctured. Head slightly transverse and evenly convex, with scattered long pubescence except on the vertex, eyes weakly convex, temples about as long as the eyes and converging to a narrow neck (at most half the interocular distance) which is usually visible from above. Basal segments of maxillary palps long and slender, penultimate segment long and dilated, terminal segment diminutive. Antennae long and slender with a gradual 4-segmented club; two basal segments subequal in length, 3-7 only slightly elongate, at most 1.5X longer than broad, 8 & 9 quadrate and 10 slightly transverse, terminal segment elongate and pointed. Pronotum slightly transverse, broadest at slightly produced and acute posterior angles and sub-parallel to obtuse anterior angles, the lateral margin not bordered, basal margin curved, apical margin produced to an obtuse median angle. Pronotal surface much more densely pubescent than the elytra, especially so towards the lateral margins, the base lacking a central ridge but with well-defined and deep fovea either side of the middle. Elytra narrowly oval and evenly convex, slightly narrower across the base than the base of the pronotum, with sloping shoulders and lateral margins evenly curved to the apex which covers or substantially covers the pygidium, without striae or fovea and with sparse recumbent pubescence lying parallel to the suture. Legs long and slender, femora strongly broadened towards the apices, tibiae only weakly so and without apical spurs. Tarsi 5-segmented and distinctly shorter than the corresponding tibia, without bilobed segments, the terminal segment about as long as the two basal segments combined. Claws smooth and without a basal tooth.