Rypobius praetermissus Bowestead, 1999
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POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
CORYLOPHINAE LeConte, 1852
RYPOBIINI Paulian, 1950
Rypobius LeConte, 1852
Known to be widespread in southern and central Europe from Spain to the western border of the Black Sea, including some of the Mediterranean islands, and extending north to the UK and into southern provinces of Fennoscandia, this species was formerly known as R. ruficollis Jacquelin du Val, 1854, and so the distribution is probably only poorly understood. In the UK it is very local and rare; it has variously been considered as extinct or represented only by specimens from Europe, but now it seems to have been present at Studland in Dorset since the 1930s and there are older (1919) records from West Sussex. Despite this very wide European distribution records are very few and tend to be widely spaced, especially in the north, no doubt reflecting the difficulty in finding and identifying the species, and so it is likely to be more frequent then records suggest. Adults have been recorded every month between February and November (in the UK from August and September); they seem to peak in abundance during late summer and it is likely they are present year-round. Little is known of the biology but adults occur under debris and among matted vegetation in salt marshes and at the margins of inland ponds and marshes etc, and they have been found under stones and at the roots of plants in dry stony fields (Bowestead, 1999). Adults may be found by carefully looking beneath stones etc or by taking suitable samples for extraction; in marshy areas samples of litter or tussocks may be successful, especially in late summer.
1.0-1.28 mm, females on average larger than males. Elongate-oval, continuous in outline and strongly convex above. Head and pronotum dark reddish-brown to dusky yellow, elytra dark brown to black with the suture narrowly paler, appendages pale brown to yellow. Head visible when viewed obliquely from in front; not concealed by the pronotal margin. Antennae 11-segmented; the basal segment enlarged and curved and segments 9-11 forming a long and loose club. Pronotum widely transverse, broadest across produced and acute (from above) posterior angles and smoothly rounded to a strongly emarginate apical margin, surface smoothly convex, without impressions or structure, very finely punctured and pubescent and with random isodiametric microsculpture. Scutellum triangular with curved margins, surface smooth. Metasternum smooth, without postcoxal lines, in males slightly depressed medially. Elytra smoothly convex, very finely punctured and with isodiametric microsculpture that forms (at least in places) transverse lines, without striae but for a short and fine sutural stria that extends about 1/3 of the elytral length from the apex. Legs short and slender with femora at most only narrowly visible from above. Front tibiae slightly broadened from the base to rounded apices, and with two fine longitudinal ridges in the apical half, middle and hind tibiae widened from the middle, all tibiae lacking apical spurs. Tarsi 4-segmented but appearing 3-segmented as the diminutive third segment is hidden within the bilobed second segment. Claws smooth and only slightly widened at the base; not toothed.