Laccobius (Microlaccobius) eximius Kuwert, 1890

Fikáček, Martin, Delgado, Juan A. & Gentili, Elio, 2012, The Hydrophiloid beetles of Socotra Island (Coleoptera: Georissidae, Hydrophilidae), Acta Entomologica Musei Nationalis Pragae 52, pp. 107-130 : 124

Laccobius (Microlaccobius) eximius Kuwert, 1890

Material examined. 6 JJ, 8 ♀♀ ( NMPC, MSNV): Haghier Mts., Wadi Madar, 12°33.2′ N, 54°00.4′E, 1180–1230 m, 12–14.xi.2010, lgt. Jiří Hájek.

Distribution. The distribution of the species is unclear due to changes of its taxonomic position by various authors until it was confirmed as a separate species by FIKÁČEK et al. (2010) (see p. 147 in the latter paper for history of the taxonomic concepts of the species). The species was described from ‘Hejaz’ and since then recorded from various parts of the Arabian Peninsula ( HEBAUER 1997, as L. praecipuus ) and Egypt ( KUWERT 1890), but most these records require confirmation as they may concern the widespread L. praecipuus . So far, the only specimens examined by us reliably belonging to L. eximius were all collected in western Saudi Arabia at high altitudes (ca. 2000 m a.s.l.) of the mountain range along the Red Sea. First record from Socotra Island.

Note. Laccobius eximius was found at a single locality at high altitude in Socotra Island. This corresponds to its distribution on the Arabian Peninsula, where the species inhabits the mountains in the western part of Saudi Arabia where it replaces the common lowland species L. praecipuus . The dorsal coloration of the Socotran specimens is paler than in the majority of the Saudi Arabian specimens which are nearly completely dark (see FIKÁČEK et al. 2010, Fig. 11 ). Pale specimens of L. eximius easily differ from L. praecipuus by darker pronotum (uniformly black on a larger surface) and elytral longitudinal puncture rows uniformly darkened (sometimes these rows join one another forming a nearly black elytral surface). The morphology of the aedeagus of the Socotran specimens agrees in all details with those from the Arabian Peninsula (see FIKÁČEK et al. 2010, Figs. 7–9 ) and L. eximius is therefore easily distinguished from L. praecipuus by genital morphology. Socotran specimens of L. eximius are generally smaller than those from the Arabian Peninsula.

Figures

Figs. 9–14. Georissus nemo sp. nov. (9–13 – paratype; 14 – holotype). 9 – pronotum and elytra in dorsal view; 10 – head, dorsal view; 11–12 – detail of pronotum (11 – dorsal view; 12 – dorsolateral view); 13 – elytron, dorsolateral view; 14 – abdomen.

Figs. 7–8. Genitalia of Socotran endemic Georissus species. 7 – G. maritimus sp. nov. (a, b: two different ventral views of the same aedeagus; c: lateral view); 8 – G. nemo sp. nov., ventral view.