Gabrius splendidulus (Gravenhorst, 1802)

A widely distributed species with modern records throughout England and Wales north to a line from the Mersey to the Wash, further north there are a few scattered records to the Scottish borders (NBN, April 2009). The actual distribution may well be wider as Joy gives simply 'Brit, local' while Fowler, who quotes the beetle as 'often found with ants' gives Scotland, Tay district, Rannoch, very rare. The species occurs throughout our Watford area and adults are sometimes common but they are rarely encountered in the field; we often extract them from samples of fungus, moss and debris taken from both standing and fallen timber. They have occured in a wide range of fungus species (mostly unidentified), including Coriolus, and on one occasion (Sept 08, Cassiobury park) among a large clump of 'mushroom' type growing in shrub beds among leaf litter. Healthy fruiting bodies as well as dried out or decaying specimens have been found to host the beetles. They occur on a range of broadleaved trees including Oak, Beech, Willow (Radlett road), Horse Chestnut and Bird Cherry (among L.sulphureus, Whippendell wood, May 2008). During March 2008 several adults were observed (apparently grazing) nocturnally on a white mat of fungus along with several Scaphidium quadrimaculatum on the undersurface of freshly cut beech logs below Cassiobury park. Adults occur year round but most of our records are from September and November.

4.5-5mm (Joy). Head and pronotum rather dull black, with fine wavy microsculpture (just visible at X40). Elytra dark brown, lighter towards apical margins. Abdomen dark brown, lighter towards apex of segments. Head quadrate or slightly elongate, with protruding mandibles. Without sculpture but usually with a faint longitudinal impression or a weak puncture at centre between two transverse pairs of punctures inside the eyes. Eyes very weakly convex; almost continuous with outline of head, diameter much shorter than temples. Temples more or less parallel, evenly rounded to hind margin. Palps pale, last segment lanceolate. Antennae dark with two or three basal segments pale, inserted in front if raised front margin of head, inside outer margin of mandibles, insertions separated by about the length of segment 1, segments 7-10 transverse, 11 asymetrical. Pronotum elongate (11:9) and subparallel, margins finely bordered, front and hind angles rounded. With a longitudinal series of 5 setiferous punctures either side of midline (sometimes with an extra puncture on one side) and 3 or 4 between these and the anterior margin. Scutellum large, pubescent and with microsculpture as pronotum. Elytra a little longer than pronotum, with prominent shoulders and dilated towards apex. Cuticle smooth and shiny, strongly and diffusely punctured and with backwardly directed pale pubescence. Hind margin sinuate. Abdominal segments 1-5 strongly bordered, cuticle shiny with fine puncturation and recumbent pubescence. Segment six finely bordered, puncturation and pubescence sparse. Legs pale or with tibiae and (or) tarsi a little darker. Femora robust and broad, especially middle pair. All tibiae with short, stout spines and a pair of terminal spurs on inside. Tarsi 5-5-5, those of male not modified. Claws small and weakly curved, smooth and without a basal tooth. Aedeagus distinctive. The aedeagus of all British species are figured by Lohse (1964).

Description from 6 Watford specimens at X40

Lohse, G.A., 1964 In Freude H et al. Die Kafer Mitteleuropas 4:188-189