Holotrochus agostii, Irmler, 2013

Irmler, Ulrich, 2013, New species of the genus Mimogonia and Holotrochus from South America (Coleoptera: Staphylindae: Osoriinae), Acta Entomologica Musei Nationalis Pragae 53 (1), pp. 155-176 : 170-174

Holotrochus agostii sp. nov.

( Figs 14 , 19A )

Type locality. Brazil, Bahia, Cerro Grande .

Type material. HOLOTYPE:, Brazil, Bahia, Urucuca, Cerro Grande (39°03.43’W, 14°25.17’S), primary Atlantic forest , 120 m elevation, 28.1.1995, leg. D. Agosti ( AMNH).

Diagnosis. This species certainly belongs to the H. syntheticus group concerning its densely pubescent abdomen. It resembles H. poundi Blackwelder, 1943 due to the shape and sparse punctation of the pronotum. However, the posterior half of the pronotum of H. poundi is more or less parallel, whereas it is slightly narrowed in H. agostii sp. nov. Nevertheless, it can be hardly differentiated from H. poundi without dissection of the aedeagus: The apical lobe of the aedeagus in H. poundi is more slender and much longer than in H. agostii sp. nov. The apical lobe of H. agostii sp. nov. is thicker and shorter.

Description. Length: 3.8 mm. Colouration dark brown; posterior margin of abdominal segments lighter brown; posterior margin and posterior angles of pronotum reddish; legs and antennae light red.

Head 0.45 mm long, 0.69 mm wide; eyes large; distinctly longer than temples; fore-head semicircular; punctation fine and sparse; interstices nearly three times as wide as diameter of punctures; two setiferous punctures on clypeus; four setiferous punctures on vertex placed in quadrate and two supraocular setiferous punctures; without microsculpture; surface polished.

Antennae slightly longer than head and half of pronotum combined; second antennomere nearly globular; conical third antennomere 1.5 times longer than second; following antennomeres distinctly increasing in width; tenth antennomere twice as wide as fourth; fourth antennomere quadrate; tenth antennomere 1.5 times as wide as long; antennomeres six to eleven with dense setation.

Pronotum 0.69 mm long, 0.97 mm wide; widest in middle; narrowed in smooth curve to anterior and posterior angles; lateral margin thick; combined with anterior margin; posterior edge not margined; margin thickest at anterior angles; punctation sparse and fine; interstices between punctures between three to four times as wide as diameter of punctures; row of setiferous punctures at anterior margin and few setiferous punctures in lateral margin; two setiferous punctures on each side at posterior edge; without microsculpture, but partly with very weak coriaceous ground sculpture; between normal punctation with sparse micro-punctation; surface shiny.

Elytra 0.83 mm long, 0.99 mm wide; with very weak punctation; nearly invisible in coarse coriaceous ground sculpture; lateral margin wide; numerous setiferous punctures in lateral margin; on anterior disc, two setiferous punctures on each side placed in longitudinal row.

Aedeagus with short apical lobe; apical lobe thick and ending in hook-like apex; endophallus slightly curved in basal part; apical part with two torsions; paramere weakly sinuate and as long as apical lobe.

Etymology. The specific name is derived from its collector D. Agosti.

Distribution. Known only from the type locality.

Figures

Figs 12–15. 12 – Holotrochus tortilis sp. nov.; 13 – H. lobatus sp. nov.; 14 – H. agostii sp.nov.; 15 – H.pseudoleticiae sp. nov. Body parts:A – aedeagus; B – antenna; C – last sternite. Scale bar: 0.1 mm.

Fig. 19. Head, pronotum, and elytra of Holotrochus Erichson, 1839 showing shape, punctation, and microsculpture. A – H. agostii sp. nov.; B – H. pseudoleticiae sp. nov. Scale bars: 0.5 mm.