Osoriellus coronatus, Irmler, 2014

Irmler, Ulrich, 2014, The Neotropical species of the genus Osoriellus FAGEL, 1959 (Coleoptera: Staphylinidae: Osoriinae), Beiträge Zur Entomologie = Contributions to Entomology 64 (2), pp. 231-354 : 234-235

Osoriellus coronatus n. sp.

( Figs 2A – E , 5A )

Type material: Holotype, male: Brazil: Amazonas, Manaus, INPA/Smithsonian Res. 2 (59°50'W, 2°25'N), leaf litter, Terra firme forest , Winkler method, male, March 1994, leg. R. Didham, #312 4 ( BMNH).

Paratypes: female with same data as holotype, but Feb. 1994, #125 2 ( BMNH) ; female with same data as holotype, but May 1994, #772 2 ( BMNH) ; female with same data as holotype, but Jan. 1994, #93 1 ( BMNH, UIC) ; French Guyana: Saül (53°12'W, 3°37'N), 1 male, 3 females 27.7.1981, leg. Perrault ( UIC, MNHN) .

Diagnosis: Currently only this species of the group can be described. It is distinctly characterised by the specific structure of the abdominal segment VII. However, similar specimens were found in Panama and Ecuador with the same spine structure at abdominal segement VII, which seem to be different species. Unfortunately, only female specimens from these countries are available that avoid a sufficient description. Nevertheless, it is supposed that more than one species can be expected in this group.

Description: Length: 2.1 mm. Colouration: Dark yellow; head light brown; elytra yellow with black posterior edge; legs and antennae yellow.

Head: 0.22 mm long, 0.36 mm wide; eyes sligthly prominent; nearly as long as temples; sides in front of eyes narrowed to anterior edge in smooth concave curve; anterior edge of clypeus even; setiferous punctation coarse and dense; yellow setae of large punctures at least as long as double diameter of punctures; interstices between punctures less than half of diameter of punctures; surface of interstices and punctures with dense isodiameteric microsculpture; surface matt.

Antennae nearly as long as head and half of pronotum combined; second antennomere oval and as thick as first antennomere; nearly twice as long as narrower third antennomere; following three antennomeres approximately quadrate and equal in width; antennomeres six to eleven increasing in width; antennomere six slightly wider than long; seven nearly twice as wide as long; antennomere ten thick and only slightly wider than long.

Pronotum: 0.32 mm long, 0.36 mm wide; widest at anterior angles; evenly narrowed in smooth curve to obtuse posterior angles; lateral margin very fine; in dorsal aspect not visible close to anterior angles; setiferous punctation sparser and less deep than on head; interstices between punctures at least as wide as diameter of punctures; yellow setae long; at least as long as double diameter of punctures; without microsculpture; surface polished and shiny.

Elytra: 0.42 mm long, 0.38 mm wide; widest in posterior third, but sides nearly parallel; setiferous punctation coarse and dense; setae pointing posteriad; ground sculpture deep; surface matt.

Abdomen with dense and deep setiferous punctation; punctures coarse and interstices less than half of diameter of punctures; without microsculpture; surface shiny; segment VII with three pairs of long spines; one dorsally in middle and two on each side.

Protibia: 0.19 mm long, 0.07 mm wide; with seven long spines at outer edge; apical spines inserted directly on outer edge; WLR: 3.0; in posterior aspect, comb at inner emargination covered in middle; posterior face with moderately dense long setation.

Aedagus stout and thick with nearly straight apical lobe; five sensillae at base of apical lobe.

Etymology: The specific name coronatus derived from the same Latin word meaning crowned and refers to the crown-like structure of abdominal segment VII.

Figures

Fig. 2-4: Osoriellus-coronatus- and –laeviusculus-group: Osoriellus coronatus (2), O. laeviusculus(3), O. schubarti (4); antenna (A), protibia (B), aedeagus in lateral aspect (C), anterior edge of clypeus (D), abdominal segment VII (E); scale bar: 0.1 mm.

Fig. 5: Osoriellus-coronatus- and –laeviusculus-group: Head, pronotum and elytra of Osoriellus coronatus (A); O. laeviusculus(B), O. schubarti (C); scale bar: 0.5 mm.