Actinopteryx fucicola (Allibert, 1844)
POLYPHAGA Emery, 1886
STAPHYLINOIDEA Latreille, 1802
ACROTRICHINAE Reitter, 1909
ACROTRICHINI Reitter, 1909
Actinopteryx Matthews, A., 1872
A maritime species associated with decaying organic matter above the high tide line on sandy coasts. The world distribution includes the Black Sea and Indian Ocean and tropical and subtropical Old World and New World Atlantic coasts, it also occurs on many islands e.g. The Maldives, Canaries, Azores and across much of the West Indies. In Europe, where the species is considered to be invasive, it has been recorded infrequently and very sporadically from Greece to the Netherlands, including some of the Mediterranean islands, and there are older records from Denmark and southern Sweden. Here it is very local and generally rare; the modern UK distribution includes parts of Dorset, Isle of Wight and East Kent but it may have declined over recent decades (or remain under-recorded) as there is a single record from Essex in the 1960s, and it was last recorded from Ireland in the 1930s. Little is known of the biology but adults and larvae are thought to feed on fungal spores, and it is likely that adults are present year-round; they have been recorded during August and September in the UK and during January and April on the continent. Despite the very local and sporadic occurrence adults may be abundant where they occur.
0.75-0.85 mm. With a very characteristic appearance; broadly elongate with the pronotum wider than the elytra, black to dark brown or with the pronotal or elytral margins vaguely paler, dorsal surface with dense decumbent pubescence. Head broadest across small asymmetric eyes that follow the outline and are situated in front of the pronotal margin, surface weakly convex, apical margin smoothly rounded from above. Antennae inserted laterally in front of the eyes, slightly longer than half the body length, two basal segments enlarged, 3-8 elongate, slender and not constricted about the base, 9-11 elongate and expanded beyond a narrow base. Pronotum transverse, broadest behind the middle and evenly curved to obtusely-rounded anterior angles and backwardly-produced and perpendicular posterior angles, apical margin straight, basal margin widely sinuate, surface finely reticulate and with two weak longitudinal depressions. Apical mesosternal margin oblique and straight from the coxae and touching the elytral margin. Scutellum triangular and slightly elongate. Elytra narrowed from rounded shoulders to separately curved and rather obliquely-truncate apical margins which leave the abdomen narrowly exposed, surface smoothly convex, without striae or impressions. Tibiae with rows of very fine setae, tarsi 3-segmented; terminal segment narrow and longer than the others combined. In males the front tibiae have a group of long fine setae at the apex, and there are three tiny projections on the pygidial hind margin, female tibiae and pygidium simple.