Cephennium (Macroderus), CROISSANDEAU, 1894

Assing, Volker, 2021, On the Cephennium fauna of the Iberian Peninsula and the Atlantic Islands (Coleoptera, Staphylinidae, Scydmaeninae), Linzer biologische Beiträge 52 (2), pp. 891-931 : 924-925

Subgenus Macroderus CROISSANDEAU, 1894

Macroderus previously included a single species, the

type species C. divergens REITTER, 1884 from Aragón (Northeast Spain).

Species of this well-defined subgenus are characterized by the following character combination: body broad and robust, strongly convex (cross-section); colouration reddish to reddish-brown; antennae slender, antennomeres VI and VIII not transverse, VII only indistinctly longer and larger than VI and VIII at most, and IX and X weakly transverse, less than 1.5 times as broad as long; eyes composed of approximately five to seven large ommatidia; pronotum strongly transverse, at least 1.25 times as broad as long, very shiny; punctation sparse and extremely fine, barely noticeable even at high magnification (100 x); pubescence long and suberect to depressed; elytra broad, strongly convex in cross-section, anteriorly with a lateral humeral carina only and with a pronounced sulcus originating from the anterior impression; hind wings reduced; metaventrite practically impunctate and very glossy; legs without appreciable sexual dimorphism; all tibiae more or less distinctly clavate, i.e., very narrow in basal half and distinctly dilated in apical half; male metaventrite more or less distinctly impressed; aedeagus with bulbous capsule, short and often broad ventral ventral process, and with internal structures partly composed of clusters of filaments; parameres thin, reaching apex of median lobe, or nearly so, and with moderately long apical seta.

Several of these characters (shape and punctation of pronotum; pronotum strongly transverse; elytra with prounced lateral humeral carina, without supra-humeral carina, and with a pronounced sulcus extending from anterior impression; metaventrite practically impunctate; all tibiae without sexual dimorphism; derived morphology of the aedeagus) are unique in the genus and partly evidently synapomorphic. For this reason, the subgeneric status Macroderus is retained for the purpose of the present paper.