Holotrochus paraguensis, 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 : 163-165

Holotrochus paraguensis sp. nov.

( Figs 10 , 18A )

Type locality. Paraguay, Puerto Presidente Stroessner .

Type material. HOLOTYPE:, ‘ Paraguay, Puerto Presidente Stroessner , Hungarian (54°36’ W, 25°31’ S) Soil-Zool. Exp., Acaray waterfall, 02.01.1966, leg. I. Loksa’ ( HNHM) . PARATYPES: 1 2 ♀♀, with the same data as holotype ( HNHM, UIC) ; 2 ♀♀ from the same location, but not from Acaray waterfall, 26.12.1965, leg, I. Loksa ( HNHM) ; 1 ♀; from the same location, but 30.12.1965, leg. L.S. Mahunka ( HNHM) ; 1 ♀, Brazil, São Paulo, without date, leg. B.J. György ( HNHM) ; 1 ♀, ‘ Paraná, Iguacú, National Park , 05.01.1966, leg. I. Loksa’ ( HNHM) .

Diagnosis. This species belongs to the Holotrochus minor group due to its small size, the absence of pubescence on the abdomen and the partly margined front edge of the pronotum. Regarding the shape of the pronotum with its more or less parallel sides, it mostly resembles H. inpai Irmler, 1981 and H. ashei Irmler, 2005 . However, the species in the H. minor group are mainly separated by the structure of the endophallus. Most other species in the group have a straight basal part and a twisted apical part of the endophallus. A throughout twisted endophallus is also developed in H. schubarti Irmler, 1981 , but in this species the endophallus developed 5 coils with a distinctly larger apical coil. Thus, the species mostly resembles H. tortilis sp. nov. that also has a twisted endophallus, but in H. tortilis sp. nov. two wide torsions are developed, while in H. paraguensis sp. nov. three short coils are existing. Furthermore, the species can be easily separated by the elytra that have rectangular shoulders in H. tortilis sp. nov., but smoothly rounded shoulders in H. paraguensis .

Description. Length: 3.0 mm. Colouration dark brown; posterior margin of pronotum and elytra, and parallel to suture of elytra, lighter reddish; legs red; antennae yellow.

Head 0.34 mm long, 0.50 mm wide; eyes slightly prominent, as long as temples; forehead smoothly rounded, with supraocular margin continuing to base of antennae; within margin four setiferous punctures; on a line between posterior edges of eyes four setiferous punctures; interstices between inner setiferous punctures nearly four times as wide as interstices between inner puncture and outer puncture; along front edge of clypeus with row of short yellow setae; irregular punctation on vertex moderately dense and deep; on average, interstices between punctures slightly wider than diameter of punctures; sparse micro-punctation on disc; at neck, punctation slightly sparser than on fore-head; surface without microsculpture, polished.

Antennae slightly longer than head; second antennomere oval, distinctly ticker than conical third; fourth antennomere as thick as third, but only half as long as third; following antennomeres increasing in width; fourth antennomere nearly quadrate; tenth antennomere nearly twice as wide as long.

Pronotum 0.54 mm long, 0.67 mm wide; widest in the posterior third; nearly parallel in middle and shortly rounded at posterior and anterior angles; sides with narrow margin from posterior angles to anterior angles and shortly continuing to anterior edge; shortly in front of anterior angles, margin hidden in dorsal aspect, but again distinctly visible at anterior angles; punctation moderately deep and dense; on average, interstices between punctures slightly wider than diameter of punctures; distinct micro-punctation between normal punctation; surface without microsculpture, polished and shiny.

Elytra 0.64 mm long, 0.69 mm wide; shoulders smoothly rounded; with finer punctation than pronotum, but with deep coriaceous ground-sculpture; surface less shiny than head and pronotum.

Abdomen with fine punctation and weak net-like microsculpture; laterally, with few setiferous punctures; surface still less shiny than elytra. Shape of last sternite triangular and with punctures and ridges at apex.

Aedeagus with straight apex and more or less straight parameres; endophallus with three short torsions and additional half apical torsion.

Etymology. The specific name is derived from the name of the country where the species was found.

Distribution. Known only from Paraguay and southern Brazil (State of São Paulo).

Figures

Figs 8–11. 8– Holotrochus yasuniensis sp. nov.; 9 – H. mrazi sp. nov.; 10 – H. paraguensis sp. nov.; 11 – H. hamatus sp. nov. Body parts:A – aedeagus; B – antenna, C – tergite XII, D – last sternite. Scale bar: 0.1 mm.

Fig. 18. Head, pronotum, and elytra of Holotrochus Erichson,1839 showing shape, punctation, and microsculpture.A – H. paraguensis sp. nov.; B – H.tortilis sp. nov.; C – H.hamatus sp. nov.; D – H.yanuniensis sp. nov.; E – H. mrazi sp. nov.; F – H. lobatus sp. nov. Scale bars: 0.5 mm.