Holotrochus adisi, 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 : 160-161

Holotrochus adisi sp. nov.

( Figs 7 , 17D )

Type locality. Brazil, Prov. Amazonas, Manaus , Ilha do Marchanteria .

Material. HOLOTYPE :: ‘ Brazil, Amazonas , Manaus , Rio Solimões, Ilha do Marchanteria (59°57.710’W, 3°14.715’S), 14.09.1981, leg. J. Adis’ ( INPA) . PARATYPES: 2 ♀♀, data as holotype, but 16.02.1982 ( INPA, UIC) ; 1 ♀, Dec. 1981 ( UIC) ; 2 ♀♀, 18.2.1982 ( UIC) ; 1 ♀, 14.9.1981 collected by emergence traps ( UIC) ; 1 ♀, 02.12.1981, collected by tree emergence trap ( UIC) ; 1 ♀, 02.05.1981, collected by tree emergence trap ( UIC) .

Diagnosis. This species is extremely similar to H. pubescens Sharp, 1876 in size, shape and matte microsculpture. It can be differentiated from H. pubescens by the longer antennae, in particular, the longer antennomeres 3 to 6. Moreover, the short emargination in front of the posterior pronotal angles differs from H. pubescens in the more obtuse angles. It differs from H. siolii Irmler, 2000 by the shape of the pronotum. As in H. pubescens , the pronotum of H. adisi sp. nov. is widest shortly behind the middle, whereas in H. siolii it is widest shortly in front of the posterior angles.

Description. Length: 3.3 mm. Colouration dark brown; legs and antennae yellow; clypeus reddish.

Head 0.40 mm long; 0.53 mm wide; eyes large, slightly prominent and as long as temples; clypeus trapezoidal; without punctation but pubescent; with long yellow pubescence; isodiametric microsculpture deep; surface matte.

Antennae nearly as long as head and pronotum combined; first antennomere rectangular and thick, second oblong, third conical; third antennomere 1.5 times as long as second and fourth; fifth and sixth antennomeres thicker than preceding antennomeres, but shorter and still longer than wide; following 4 antennomeres more or less globular.

Pronotum 0.54 mm long, 0.67 mm wide; widest behind middle; smoothly narrowed in convex curve to anterior angles; anterior angles not visible in dorsal aspect; in front of posterior angles shortly emarginate; posterior angles nearly rectangular; with oval depression at posterior angles; sides crenate and without margin; disc without punctation, but long yellow pubescence; pubescence on lateral part pointing transversely to central posterior edge; at posterior depressions pointing to posterior angles, and along midline pointing posteriad; isodiametric microsculpture distinct; surface matte.

Elytra 0.87 mm long, 0.90 mm wide; without punctation, but with same yellow pubescence as on head and pronotum; hairs pointing posteriad; isodiametric microsculpture deep; surface matte.

Abdomen with similar pubescence as on fore-body, but microsculpture less distinct; thus, surface less matte; last tergite trapezoidal and with short teeth at outer angles.

Aedeagus with short basal part and longer apical part; apical part smoothly curved to acute apex; parameres S-shaped; endophallus with short straight basal part and irregularly spiralled apical part.

Etymology. This species is named in honour of the late Prof. Joachim Adis, a former colleague of mine who collected it during his investigations in the floodplains of the Varzéa of the Rio Solimões.

Distribution. Known only from the type locality

Figures

Figs 4–7. 4 – Holotrochus pubescens Sharp, 1876; 5 – H. siolii Irmler, 2001; 6 – H. amazonicus Irmler, 1981; 7 – H. adisi sp. nov. Body parts: A – aedeagus in lateral aspect; B – antenna. Scale bars: A – 0.1 mm, B – 0.5 mm.

Fig. 17. Head, pronotum, and elytra of Holotrochus Erichson, 1839 showing shape, punctation, and microsculpture. A – H. pubescens Sharp, 1876; B – H. amazonicus Irmler, 1981; C– H. siolii Irmler, 2001; D – H. adisi sp. nov. Scale bars: 0.2 mm.