Phalacronothus quadrimaculatus (Linnaeus, 1760)
This is a very widespread Palaearctic species; it extends east from Portugal through Asia Minor, Ukraine and Russia to eastern Siberia, across North Africa from Morocco to Syria and Turkey, and to the north it extends sporadically to the UK and southern provinces of Fennoscandia. On the continent the species occurs in a wide range of habitats from lowlands to low mountain altitudes although it is xerothermic and more-or-less restricted to dry, and well-drained soils, hence it is locally common in the south but tends to be rare and very local in the north where its presence in many countries is known from only a few records and in many cases these tend to be old and there seems to have been a general decline over the 20th century. In the UK it was formerly widespread in the south of England and there are old records from South Wales and Scotland but it is now very rare, it is classed as Critically Endangered and has sometimes been considered extinct; since 1950 it has been recorded only from East Sussex (1988) and Gloucestershire (2016). Adults occur from April until July although they are thought to overwinter and so might occur much earlier, and in mountain areas on the continent they have been recorded into August, here they occur among sheep and cattle dung on dry pasture, often on chalk downland, but more generally they have been found among deer and cattle droppings and in the burrows of small rodents.
3.0-4.0mm. Adults are easily recognized by the small size and elytral markings, the only UK species likely to cause confusion is Otophorus haemorrhoidalis but here the scutellum is much longer; between one third and one fifth the elytral length, in the present species it is at most one eighth the elytral length. Head and pronotum black, elytra dark brown to black, each with a small and well-defined red spot beneath the humerus and a larger red subapical macula which usually extends across interstices two to five, legs, palps and antennae pale to dark brown. Head obliquely and narrowly expanded in front of the eyes and widely curved anteriorly, cuticle roughly sculptured and appearing duller than the pronotum, punctures mostly wide and shallow. Pronotum broadest in front of obtuse posterior angles and evenly curved to obtuse anterior and posterior angles (from above), surface evenly convex, very finely microsculptured and with a mixture of fine and very fine punctures. Scutellum triangular with gently curved lateral margins. Elytra broadest a little behind the middle and continuously curved apically, striae complete and finely punctured to the apex, interstices flat or only weakly convex before the apex, each with several confused rows of very fine punctures. Males have a distinct, although sometimes weak, tubercle on the centre of the clypeus.
Phalacronothus quadrimaculatus 1
Phalacronothus quadrimaculatus 2