Osoriellus sexdentatus, 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 : 239

Osoriellus sexdentatus n. sp.

( Figs 9 A-D, 11E)

Type material: Holotype, male: French Guiana: Wanaboo (near Nason) Marowijne River , 40 m elevation (54°26.36'W, 4°43.35'N), ex flight intercept trap, 31.5.- 5.6.1999, leg. Z.H. Falin & B. DeDijn, SUR1F99 032 ( KNHM).

Diagnosis: The species resembles O. ocularis and O. oculatus by its large prominent eyes. The eyes are similarly large as in O. oculatus and, therefore, slightly smaller than in O. ocularis . The front edge of the clypeus is similar as in O. ocularis , but with only four teeth between the larger outer teeth and not with six teeth as in O. ocularis .

Description: Length: 4.0 mm. Colouration: Black; elytra and abdomen brown; legs and antennae light brown.

Head: 0.63 mm long, 0.79 mm wide; eyes prominent; longer than temples; sides of fore-head evenly convergent; angles of clypeus produced to long teeth and four smaller teeth on anterior edge; punctation dense and coarse and with impunctate midline on vertex; clypeus with isodiametric microsculpture; surface slightly shiny; vertex without microsculpture; surface polished and shiny; several setiferous punctures at upper margin of eyes; two setiferous punctures on vertex and several setiferous punctures on clypeus.

Antennae slightly longer than head; with second antennomere oblong and thicker than conical third antennomere; following 3 antennomeres as wide as third, but quadrate; antennomeres 7 to 11 distinctly thicker than preceding antennomeres; more or less quadrate.

Pronotum: 0.76 mm, 0.81 mm wide; widest at anterior angles; slightly narrowed in anterior two-third; in posterior third abruptly more strongly narrowed; setiferous punctation large and in irregular rows; within row interstices between punctures only half as wide as diameter of punctures; between rows interstices as wide as diameter of punctures; without microsculpture, but with sparse micro-punctation; surface polished and shiny.

Key to the species

1. Eyes large and distinctly prominent, temples shorter than eyes. .................................................................... 3

- Eyes not or slightly prominent, as long as temples. ................................................................................... 2

2. Front edge of clypeus with 8 teeth between tooth-like angles. .......................................... O. hanagarthi n. sp.

- Front angles of clypeus produced to long bidentate teeth. ............................................ O. denticornis n. sp.

3. Between 4.2 and 4.7 mm long, anterior edge of clypeus with 3 short lateral teeth and even slightly prominent middle. .............................. O. oculatus ( SHARP, 1876)

- Between 3.7 and 4.0 mm long, anterior edge of clypeus with more than 3 teeth. ............................................. 4

4. Clypeus with 6 short teeth between long teeth at angles. ............................................... O. ocularis n. sp.

- Clypeus with 4 short teeth between long teeth at angles. ........................................ O. sexdentatus n. sp.

Elytra: 0.96 mm long, 0.87 mm wide; with coriaceous ground-sculpture and weak setiferous punctation; interstices between punctures at least as wide as diameter of punctures.

Abdomen densely punctate; with large setiferous punctures; yellow setae pointing posteriad; without impunctate midline.

Protibia: 0.50 mm long, 0.13 mm wide; with 8 spines at outer edge; apical spines inserted on moderately long digits; WLR: 1.0; in posterior aspect, comb at inner emargination visible throughout its total length; posterior face densely covered by long yellow setae.

Aedeagus with triangular apical lobe and several sensillae at inner edge.

Etymology: The specific name refers to the 6 teeth at the anterior edge of the clypeus.

Figures

Fig. 6-10: Osoriellus-oculatus-group: Osoriellus ocularis (6), O. oculatus (7), O. hanagarthi (8) O. sexdentatus (9) O. denticornis (10); antenna (A), protibia (B), aedeagus in lateral aspect (C), anterior edge of clypeus (D); scale bar: 0.1 mm.