Plegaderus (Plegaderus), 1834

Lackner, Tomáš & Vienna, Pierpaolo, 2017, Histeridae of Socotra (Coleoptera: Histeroidea), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57, pp. 55-76 : 65

publication ID 10.1515/aemnp-2017-0107

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Plegaderus (Plegaderus)


Plegaderus (Plegaderus) sp.

(Fig. 23)

Material examined. YEMEN: SOCOTRA: 1 ♀, Al Haghier Mts., Wadi Madar, 12°33.2′N, 54°00.4′E, 1180–1230 m, 12.–14.xi.2010, P. Hlaváč lgt. ( TLCM).

Comments. Genus Plegaderus Erichson, 1834 contains two subgenera: monotypic Hemitrichoderus Reichardt, 1941 with a single species P. (H.) adonis Marseul, 1876 described from Cyprus and also occurring in Turkey, and the nominotypical subgenus, which contains 27 species spread mostly in the Holarctic Region ( MAZUR 2011). The species from Socotra belongs to the group of species with deeply impressed median stria on pronotum, dividing it into two convex parts ( Fig. 8 View Figs 6–12 ). Other species of this group are: P. (P.) caesus (Herbst, 1791) , spread across Europe, Turkey, Azerbaijan and north Iran; P. (P.) dissectus Erichson, 1839 spread across southern England, central and south Europe, Turkey and north Iran; and the extremely rare P. (P.) fortesculptus Reitter, 1897 described from Azerbaijan and occurring also in Iran ( MAZUR 2011). In fact, the type specimen of P. (P.) fortesculptus was discovered only recently (LACKNER, unpublished). SECQ & SECQ (1991) beautifully depicted the two former species in their key to French Plegaderini. Of the three, the species from Socotra most resembles Plegaderus (P.) caesus , which likewise possesses a string of tiny, equally distanced granules along lateral pronotal margins. The Socotran species differs, however, from P. (P.) caesus , in its smaller size, anteriorly narrowed pronotum; less impressed punctation of the elytra, in more dilated apices of protibia, body shape more rounded; the shape of prosternum, as well as in other characters. The herein depicted specimen from Socotra ( Fig. 8 View Figs 6–12 ) most likely belongs to a new species, we are, however, reluctant to describe it based on a single female. This is the first record of the genus Plegaderus from the Afrotropical Region, to which the Socotran Archipelago biogeographically belongs.