Diochus formicetorum BERNHAUER, 1927

Irmler, Ulrich, 2017, A review of the Neotropical genus Diochus ERICHSON, 1840 (Coleoptera: Staphylinidae: Staphylininae), Beiträge Zur Entomologie = Contributions to Entomology 67 (1), pp. 1-62 : 55-56

Diochus formicetorum BERNHAUER, 1927

Figs 40K , 45F

Diochus formicetorum BERNHAUER, 1927: 244

Type material: female, Holotype: Argentina, Santa Fé, Five Lille, with Acromyrmex heyeri , leg. Weiser ( FMNH).

Additional material studied: Paraguay: Guairá, Melagarejo, Tacuara Creek , flood detritus, female, 20.10.1994, leg. U. Drechsel ( KNHM) .

Diagnosis: Only two females of Diochus formicetorum could be studied. However, they are clearly differentiated from the other Neotropical species of Diochus by its small eyes, the distintly divergent head, and the light colouration. The other species with such small eyes are darker, e.g. D. newtoni , D. verhaaghi , or have shorter eyltra, e.g. D. mexicanus , D. panamaensis . The shape of the spermatheca let suppose that the species belongs to the D. inornatus-group.

Description: Length: 2.9 mm. Colouration: yellow; abdomen light brown.

Head: 0.41 mm long, 0.38 mm wide; eyes not prominent; small; EL: HL = 0.14; temples distinctly divergent posteriad; PW: EW = 1.31; setiferous punctation moderately deep and dense; adjacent to impunctate midline with row of five punctures; between medial row and eyes two rows of supraocular punctures; temples distinctly denser punctate than vertex; partly with remains of transverse microsculpture; mostly polished.

Antennae slightly longer than head and half of pronotum combined; first antennomere twice as long as apical width; wider at apex than at base; second and third antennomere conical; nearly twice as long as apical width; fourth to tenth antennomere decreasing in length and slightly increasing in width; fourth antennomere approximately quadrate; tenth antennomere nearly twice as wide as long; all antennomeres pubescent and with short apical setae.

Pronotum: 0.46 mm long, 0.36 mm wide; widest in anterior third; apical third smoothly curved; nearly semicircular; posterior half slightly narrowed to posterior angles; posterior angles obtusely curved; lateral margin fine; in dorsal aspect visible in posterior third; setiferous punctation sparse; along impunctate midline with row of three pairs of punctures; interstice between anterior pair more than twice as wide as interstices between posterior pairs of punctures; laterad few more setiferous punctures; along lateral margin several setiferous punctures; without microsculpture; surface polished.

Elytra: 0.47 mm long, 0.38 mm wide; shoulders obtusely angled; sides parallel; posterior angles rectangular; setiferous punctation in irregular rows; inner row adjacent to suture line; two more rows on disc with five punctures; along lateral margin with several setiferous punctures; surface with weak coriaceous ground-sculpture; surface slightly less shiny than pronotum and head.

Abdomen with dense pubescence.

Aedeagus unknown.

Spermatheca 0.21 mm in diameter; bursa copulatrix in central position to coiled duct; coiled duct forming circle.

Figures

Figs 45: Fore-bodies of Diochus santacatarinae (A), D. perplexus (B), D. parvulus (C), D. nanus (D), D. apicipennis (E), D. formicetorum (F); scale bar: 0.5 mm.

Fig. 40: Spermatheca of Diochus schaumii-group: Diochus argentinae (A), D. brunneus (B), D. curtipennis (C), D. schaumii (D), D. verhaaghi-group: D. verhaaghi (E), D. santacatarinae (F), D. nanus-group: D. perplexus (G), D. parvulus (H), D. nanus (I), D. apicipennis (J), D. formicetorum (K); scale bar: 0.1 mm.