Elaphrus uliginosus Fabricius, 1792
This is a generally very local and rare species throughout central and northern Europe, extending north to the Arctic Circle in Scandinavia and east through Asia Minor and Caucasus to eastern Siberia and through much of this range it is thought to be in decline or threatened e.g. in Denmark there are only 5 post-1950 records. In the UK it is widespread though very local across Wales and there are recent records from the south coast, Norfolk and the Scottish Highlands. The typical habitat is open and permanently wet marginal substrates with patchy vegetation beside lakes, ponds and marshes; adults occur year-round; they are active from early spring until late summer and breed early in the year. On the continent they often occur in coastal situations, generally among densely vegetated fens etc. but also on acid heathland and often in association with Blethisa and various Agonum species. In central Europe they prefer more densely vegetated habitats than the common E. cupreus, occurring on permanently damp cattle grazed grassland with low proportions of exposed soil.
Of a similar size and appearance to E. cupreus but distinguished by the proportionally narrower head and strongly rounded pronotal outline. 8.0-10.0mm. Metallic dark coppery-green with purple elytral depressions and entirely dark metallic appendages. Head no wider than the pronotum; vertex uneven and densely punctured, frons strongly punctured and with only traces of striae. Pronotum transverse, strongly rounded laterally and sinuate before acute posterior angles, surface densely punctured and with wide shallow fovea which are generally a paler green than the surrounding cuticle. Prosternum glabrous. Elytra widest behind the middle and only gently narrowed to the base, each with four series of round, densely punctured depressions and raised elongate ‘mirrors’, the surface very uneven, weakly microsculptured and densely punctured.