Trissemus socotranus, Hlaváč & Baňař, 2014

Hlaváč, Peter & Baňař, Petr, 2014, A review of the Pselaphinae (Coleoptera: Staphylinidae) from Socotra Island, Acta Entomologica Musei Nationalis Pragae 54, pp. 121-132 : 122-125

Trissemus socotranus sp. nov.

( Figs 2–5 )

Type material. HOLOTYPE: J ( NMPC): (p) ‘ YEMEN, Socotra, Aloove area , Hassan vill. env. 221 m, 12°31.2′N, 54°07.4′E, 9-10.xi.2010, P. Hlaváč, at light’ . PARATYPES: 2 JJ, 1 ♀: same data as holotype ( NMPC, PHCP) ; 1 J: (p) ‘ YEMEN, Socotra, wadi Ayhaft , 12°36.5′N, 53°58.9′E, 200m, 7-8.xi.2010, J. Hájek leg.’ ( NMPC) ; 4 JJ, 2 ♀♀: (p) ‘ YEMEN, Soqotra Is., 2003,2-3/xii., Dixam plateau,WADI ESGEGO, 300m, N12°28′09′′, E54°00′36′′ [GPS], David

Král lgt. / (p) YEMEN – SOQOTRA 2003 Expedition; Jan Farkač, Petr Kabátek & David Král’ ( NMPC, PHCP) ; 1 J: (p) ‘ YEMEN, Soqotra Is., 21.xi.-12.xii.2003, HADIBOH env., ca 10-100m, N12°65′02′′, E54°02′04′′ [GPS], David Král lgt. / (p) YEMEN – SOQOTRA 2003 Expedition ; Jan Farkač, Petr Kabátek & David Král’ ( PHCP) ; 1J: (p) ‘ YEMEN, Soqotra Is., 28-29.xi. 2003, HOMHIL protected area, N12°34′27′′, E54°18′32′′ [GPS], Jan Farkač lgt. / (p) YEMEN – SOQOTRA 2003 Expedition ; Jan Farkač, Petr Kabátek & David Král’ ( NMPC) ; 3 JJ, 2 ♀♀: ‘ YEMEN: Socotra isl., Ayhaft , 15.iii.2000, Leg. Bejček & Šťastný’ ( CULS, NMPC) ; 1 J, ‘ YEMEN: Socotra isl., Zerik , 25-27.iii.2001 ’ ( NMPC) .

Description. Body shiny, pale yellowish-brown, maxillary palpi, antennae and legs lighter, yellow. Body length: 1.80–1.95 mm, width 0.82–0.85 mm, whole dorsum smooth, impunctate, with fine, short pubescence.

Head dorsally flattened, with large, subequal frontal and vertexal foveae, temples short, round; eyes very large, protuberant; maxillary palpi ( Fig. 5 ) large, palpomere I transverse, II slightly pedunculate, III about as long as wide and about 0.35 times shorter than II, palpomere IV about 1.50 times as long as II and 2.30 times as long as wide, apical pseudosegment small, about 7.50 times shorter than palpomere IV. Antennae ( Fig. 3 ) about 0.70 mm long, scape about as long as pedicel but more robust, pedicel about as long as III, antennomere III 1.50 times as long as IV, antennomere V as long as IV, both elongate, antennomeres V–X transverse, modified, all with more or less developed lateral projection, X almost three times as wide as long, terminal antennomere five times as long as X and more than twice as long as pedicel.

Pronotum about 1.25–1.35 times as wide as long and about 1.10 times as long as head, widest at mid-length, slightly convergent in basal half and shortly parallel before base, with pair of deep lateral foveae and smaller median antebasal fovea.

Elytra about 1.30–1.35 times as wide as long, with three laterobasal foveae, sutural and humeral foveae prolonged mesally by striae, humeral striae reaching apical quarter and sutural striae reaching apex of elytra.

Abdomen slightly shorter and slightly narrower than elytra, first visible (IV) tergite about twice as long as second (V), with two short, oblique discal carinae almost reaching basal third of tergite length, distance between carinae 0.35 of basal width of tergite, paratergites IV–VI well-developed.

Legs. Mesotibiae ( Fig. 4 ) with robust subapical spur.

Aedeagus as in Fig. 2 .

Sexual dimorphism. Females similar to male, but with unmodified, simple antennae, and lacking robust subapical spur on mesotibiae.

Differential diagnosis. Trissemus Jeannel, 1949 with 175 species and 11 subspecies is one of the largest genera of the subfamily Pselaphinae . The regions closest to the island of Socotra, the Arabian Peninsula (12 taxa) and East Africa (27 taxa) are relatively species-poor compared to tropical Africa and Asia (114 taxa). Madagascar and South Africa host 16 species, and the rest of the Palaearctic region holds 17 species and subspecies (A. F. NEWTON & P. HLAVÁČ, unpublished data). Trissemus socotranus sp. nov. can be easily separated from all other species by: 1) modified structure of antennomeres VI–X in male; 2) first visible (IV) tergite about twice as long as second (V), with two short, oblique discal carinae almost extending through the basal third of tergite length, distance between carinae 0.35 of basal width of tergite, paratergites IV–VI well-developed; 3) mesotibiae with robust subapical spur; and 4) shape and structure of the aedeagus.

Etymology. Named after Socotra Island, place of the discovery of this species.

Collection circumstances. All specimens were collected at light in arid areas.

Figures

Figs 1–2. Aedeagus, dorsal aspect. 1 – Trissemus marocanus wittmeri Besuchet, 1981; 2 – Trissemus socotranus sp. nov. Scale bars in mm.

Figs 3–5. Trissemus socotranus sp. nov. 3 – left antenna, antennomeres II–XI; 4 – left tibia and tarsus; 5 – left maxillary palpus. Scale bars in mm.