Disarthricerus bruneicus, Nakládal & Hlaváč, 2018

Nakládal, Oto & Hlaváč, Peter, 2018, New species and records of Clavigeritae (Coleoptera: Staphylinidae: Pselaphinae) from Africa and Asia, Zootaxa 4402 (3), pp. 595-600 : 596-597

Disarthricerus bruneicus sp. nov.

( Figs 4–6 )

Material examined: 1 ♂: BRUNEI: Labi, Bukit Teraja 60m, Mxt. dipt. forest, B.M. 1983-39 / Light trap 4, 1m above ground, 21 viii 79, S.L. Sutton. BMNH.

Description: Body ( Fig. 4 ) entirely reddish-brown, shiny, with fine pubescence, vertex of head shagreened, pronotum smooth, elytra on disc with nett-like microsculpture, abdomen smooth. Length 1.28 mm, maximum width of elytra 0.57 mm.

Head widest across eyes, about as long as wide, temples very short, significantly shorter than very large eyes, composed from about 16–17 large facets, distance between eyes inferior to transverse diameter of eyes, frontal and vertexal fovea absent, rostrum triangularly projecting anteriad. Clypeus well-visible dorsally on sides.

Antennae long, with three antennomeres, scape and pedicel minuscule, completely hidden in large antennal cavity, not visible dorsally, terminal antennomeres long, bent in basal fourth, almost 5 times as long as wide, at apex rounded, with long setae.

Pronotum pentagonal, 0.85 of length of head, strongly divergent posteriad, with well-defined posterior sharp corners, longest in middle with strong triangular projection, posterior part about 2.3 times as wide as anterior part, lacking foveae and sulci but with short median basal depression.

Elytra 1.4 times as wide as long, 1.9 times as long as pronotum, lacking basal foveae, striae or carinae, with two short ribs in humeral part, elytral trichomes absent.

Abdomen 1.80 times as wide as long, about twice shorter than elytra, composite tergite (IV–VI) simple, lacking basal depression or carinae, with very narrow paratergites, first paratergites bearing narrow trichomes.

Legs short, mid femora large, with large spines, mid tibiae bent in basal half.

Aedeagus ( Figs 5, 6 ) about 0.14 mm long and 0.08 mm wide, about twice as long as wide, basal bulb large, apex with three lobes, slightly shorter than basal bulb, median lobe shorter than lateral, lateral equal in length and shape, ventrolateral foramen projecting, phallobase diaphragm circular, about 1.6 of length of basal bulb.

Sexual dimorphism. Females unknown but most probably lacking spines on mid femora.

Differential diagnosis: Disarthricerus was erected by Raffray (1895) for Disarthricerus integer based one female collected in Singapore. Later on Bryant (1915) added a second species, D. moultoni , collected in the colony of Paratrechina butteli (Forel, 1913) ( Hymenoptera : Formicidae ) in Sarawak (Borneo). Disarthricerus bruneicus and D. integer are readily separated from D. moultoni by having antennae clearly longer than head (about as long as head in D. moultoni ), D. bruneicus differs from D. integer by terminal antennomere bent in basal forth against straight, pronotum pentagonal against hexagonal and larger size, 1.28 mm against 1.20 mm.

Biology: Unknown.

Distribution: Brunei.

Etymology: Locotypic, named after Brunei, country of its discovery.

Figures

FIGURES 1–9. Monodiger ivoricus, 1—habitus; 2—aedeagus, dorsal; 3—aedeagus, lateral; Disarthricerus bruneicus, 4— habitus; 5—aedeagus, dorsal; 6—aedeagus, lateral; Fustigerinus formicarius, 7—habitus; 8—aedeagus, dorsal; 9—aedeagus, lateral.