Antennae with a 2-segmented club. Upper surface densely hairy. Elytra with clearly punctured striae. Tibiae broadened towards the tip; first three segments of the tarsi little different in length. Last segment of the maxillary palps slender, truncate; labial palps axe-shaped. Sides of the pronotum finely toothed with a backwardly-curved hair on each tooth; pronotum with two longitudinal ridges parallel to the sides. Four species in Europe or which two are only found on the Canary Islands.
Elytra with pale spots. [Abb.1] Larger species - 3.0-3.3 mm. Brownish-black, often with reddish-brown shoulders. Elytra broadest beyond half way and with a pale zigzag band across both; each elytron with a small pale spot before the tip. A few patches on the pronotum have paler hairs. Associated with the irregular ball-shaped black fungus Daldinia which is found on dry branches of deciduous trees, particularly on ash (e.g. D. concentrica), in which the larvae develop. Very scattered and rare in western Germany, Czech Republic and Austria; more common in England.
Upper surface uniform in colour and smaller, 2.3-2.8 mm. Narrower and more parallel-sided than lunatus, similar to Diplocoelus fagi but smaller with the head and pronotum with a distinct leathery texture with the punctures very fine and dispersed. Southern and eastern Europe, Slovakia to Austria. Very rare. .
...frater (Aubé, 1850)
I have collected a specimen from Greece (Pelponnese) [Abb.2], which appears to belong to this species. However the puncturation of the head, pronotum and elytra is coarser than in Diplocoelus fagi thus disagreeing with Ganglbauer's description. [Abb.3]. The eyes are clearly covered with erect hairs (D. fagi has eyes with a few short hairs). The upper surface is uniformly hairy but they are rather curly in the middle. It has two types of hairs with the longer ones quite upright. The pronotum is less strongly narrowed towards the front than in lunatus. [Abb.4]. The club of the antennae is made of two segments. The tarsi have long lobes on the second and third segments. [Abb.5].