Osoriellus tunariensis n. sp.

(Figs 85 A-C, 102C)

Type material: Holotype, male: Bolivia: Cochabamba, Villa Tunari, 800 m elevation, 17.10.1981, leg. M. Cooper (BMNH).

Diagnosis: Both the total size and the shape of the pronotum of O. tunariensis are similar to O. argentinus . The species can be differentiated from the other species by the large prominent eyes and the contrast between the dense microsculpture of the head and the weak pronotal microsculpture.

Description: Length: 5.6 mm. Colouration: Black; legs and antennae lighter brown.

Head: 0.84 mm long, 1.26 mm wide; eyes prominent; distinctly longer than temples; sides of fore-head slightly emarginate to anterior angles of clypeus; anterior edge of clypeus even; setiferous punctation deep and dense; on vertex, partly coriaceously punctate; on central posterior vertex and at base of antennae impunctate; on supraocular area, punctures granulate; netlike microsculpture dense and deep; surface matt.

Antennae lost.

Pronotum: 1.14 mm long, 1.30 mm wide; widest at anterior angles; slightly convergent in even curve to shortly rounded posterior angles; lateral margin fine; finer at anterior angles than at posterior angles; anterior angles produced to very short acute teeth; setiferous punctation coarse and deep; impunctate midline widened from anterior margin to posterior margin; on average, interstices between punctures half as wide as diameter of punctures; microsculpture extremely weak; surface shiny.

Elytra: 1.40 mm long, 1.36 mm wide; with dense and deep coriaceous ground-sculpture; setiferous punctures in irregular rows; surface matt.

Abdomen with dense setiferous punctation; on tergites narrow midline impunctate; moderately weak netlike microsculpture; on impunctate midline weaker than on punctate area; surface of puntate area matt; midline shiny.

Protibia: 0.70 mm long, 0.26 mm wide; 9 spines at outer edge; WLR: 1.4; in posterior aspect, comb at inner emargination visible throughout its total length; posterior face very densely covered by yellow setae.

Aedeagus rectangularly angulate; apical lobe thick; ending in obtuse apex; inner edge of apical lobe with numerous sensillae.

Etymology: The specific name refers to the Bolivian village Villa Tunari, where the species was found.