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Trixagus obtusus (Curtis, 1827)





POLYPHAGA Emery, 1886


THROSCIDAE Laporte, 1840

Trixagus Kugelann, 1794

This very local and generally rare species occurs sporadically across Europe from Portugal to Greece though it is absent from much of the Balkan Peninsula and the southern Baltic countries, to the south it extends to North Africa and Asia Minor and is present on the Madeira Islands, and to the north it reaches the UK and into central provinces of Fennoscandia. In the UK it is locally common in southeast England and East Anglia and rather less so from the Severn catchment extending into the midlands. Adults occur throughout the year and, at least in Europe, are recorded more frequently between autumn and spring, they usually occur in among moss and damp litter in wetland areas and occasionally under damp bark on trees and logs, while in northern Europe they also occur in damp areas in extensive deciduous and coniferous woodland. Adults are usually found among moss tussocks but they sometimes visit flowers where they feed on pollen and fungal spores. Little is known of the bionomics but larvae are thought to develop in spring and early summer, feeding on fungi among decaying leaf litter etc. The most productive sampling method is sieving litter from marginal areas or taking samples for extraction, they appear among tussock samples and occasionally in flight interception traps and will usually occur in numbers where found.

1.5-2.5 mm. Elongate-oval and continuous in outline, with short legs and clubbed antennae, finely pubescent throughout and variable in colour from dark reddish-brown to pale yellowish-brown. Distinguished among our UK fauna by the form of the eyes and the smooth frons. Head transverse, from above evenly curved anteriorly, with large and deeply incised eyes and smoothly convex frons which lack longitudinal keels (look very carefully), labrum free and curved anteriorly. Antennae inserted laterally in front of the eyes, 11-segmented with a long and asymmetric club. Pronotum transverse, broadest near strongly produced posterior angles and narrowed to obscure anterior angles, apical margin straight, basal margin strongly bisinuate, surface evenly convex and without distinct impressions, finely and rather densely punctured throughout. Elytra smoothly curved and narrowed from rounded shoulders to a continuous apical margin, with finely impressed and punctured striae complete to the apex and finely rugose and punctured interstices; towards the base the first interstice with three distinct rows of punctures, the third and fourth with two rows and the fifth with a single row. Legs short and flattened with femora widely visible in normal setting. Front tibiae narrow and curved, middle tibiae broader and sinuate externally, hind tibiae almost parallel-sided, all tibiae lacking terminal spurs. Tarsi with five simple segments, claws smooth and without a distinct basal tooth.

Trixagus obtusus

Trixagus obtusus

© Lech Borowiec

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