Sunius propinquus (Brisout de Barneville, 1867)

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POLYPHAGA Emery, 1886

STAPHYLINOIDEA Latreille, 1802

STAPHYLINIDAE Latreille, 1802

PAEDERINAE Fleming, 1821

PAEDERINI Fleming, 1821

Sunius Stephens, 1829

This is a mostly western and southern European species, it extends north from Spain to Poland and the UK although it becomes rare in the north e.g. its presence in Poland is based on a single coastal record, and it was formerly recorded from southern Sweden but this is in doubt because there are no preserved specimens. To the south it is generally common and is the most frequently recorded member of the genus, it extends from Spain to Italy and Austria; it is widespread across North Africa and occurs on the Atlantic and many Mediterranean islands. In the UK it is locally common across southeast and central England north to Yorkshire, much more local and generally rare in the West Country and further north, and local and mostly coastal in Wales. Adults occur in a wide range of open and damp habitats including grassland, arable land and coastal dunes, they are also quick to colonize disturbed habitats such as parks and gardens and may occur in domestic compost heaps. They generally occur among decaying leaf-litter and matted grass etc. and are often to be found in cracks in damp soil, they are present year-round and active over a long season from early spring, they overwinter in tussocks or under debris and are frequently active during the winter. Locally we find them in numbers through the winter among leaf-litter in furrows around arable fields but they vanish in the spring and probably move out among the developing crops. Very little is known of the biology but so far as is known all members of the subfamily are predaceous both as adults and larvae, and it is likely that the species is a spring breeder. Adults are easily sampled by sieving appropriate material and they often occur among winter extraction samples from tussocks and litter.

Sunius propinquus

Sunius propinquus

3.5-4.0 mm.  The shape of the head and pronotum, together with the microsculpture and overall colour make this species distinctive among our fauna. Head black or dark brown but sometimes paler towards the base, pronotum orange, elytra dark brown, abdomen dark brown to black, legs pale brown to yellow, mouthparts pale but palps may be extensively darkened, at least the penultimate maxillary palpomere, antennae pale but usually with some dark central segments. Margins of head and pronotum with scattered long dark setae which are obvious from above. Head with small, weakly convex eyes situated near the anterior margin and long, parallel temples that curve to an almost straight basal margin, surface smoothly and weakly convex, slightly raised behind the antennal insertions but without frontal furrows, moderately strongly punctured throughout, the punctures mostly separated by more than their diameter, anteriorly with elongate and mostly transverse microsculpture which fades from the middle and is absent across the base. Penultimate maxillary palpomere broadened from the base and much larger than the diminutive terminal segment. Antennae inserted dorsally within the base of the mandibles, 11-segmented and filiform, the basal segment longer than the second but a little shorter than the second and third combined. Pronotum quadrate or nearly so, about as wide as the head and elytra, lateral margins slightly narrowing from obtusely-rounded anterior angles to a rounded basal margin, anterior margin converging to a broad neck, surface punctured throughout except for a smooth median line, the punctures discrete and stronger than those on the head. Elytra elongate and parallel sided, with rounded shoulders and basal margins converging to the suture, surface closely punctured and finely pubescent throughout. Abdomen strongly bordered and usually dilated about the middle, finely punctured and pubescent throughout, the apical tergites with erect setae, the eighth sternite with a small apical incision in the male. Femora long and robust, especially the anterior pair, tibiae slender and with weak apical spurs. Tarsi slender, the anterior tarsi similar between the sexes, basal segment of hind tarsi longer than the second segment and not obscured by a fringe of bristles at the apex of the tibia.