Diochus tricolor, Irmler, 2017

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 : 18-19

publication ID

https://doi.org/ 10.21248/contrib.entomol.67.1.001-062

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scientific name

Diochus tricolor

spec. nov.

Diochus tricolor spec. nov.


Figs 13A–C View Figs 10–13 ; 39C View Fig , 43B View Figs 43

Type material: male, Holotype: Brazil: Mato Grosso, 40 km S Poconé, Rio Clarinho (51°43.37'W, 16°36.38'S), decay fruit, 15.3.2013, leg. U. Irmler ( UFMT). GoogleMaps

Paratypes: 1 male, 1 female, with same data as holotype ( UIC); Peru: Madre de Dios, Dept., Tambopata , litter at swamp edge GoogleMaps , 4 females, 28.10.1982, leg. L.E. Watrous & G. Mazurek ( FMNH) .

Diagnosis: The species is characterised by the black head in contrast to the light yellow pronotum and the slightly darker elytra. It is the smallest species of the group. It can be separated from the similarly small D. antennalis by the colouration: D. tricolor with black head, D. antennalis totally light yellow. The funnel-like widening of the basal inner duct and the presence of an apical filamentous duct show that it belongs to the D. inornatus-group. In contrast to the slightly apically widened paramere of D. antennalis , the paramere of D. tricolor is more slender.

Description: Length: 2.9 mm. Colouration: head black; pronotum yellow, elytra yellowish brown; abdomen brown; legs and antennomeres one to three yellow; four to eleven dark.

Head: 0.43 mm long, 0.36 mm wide; eyes slightly prominent; temples twice as long as eyes; EL: HL = 0.25; temples distinctly divergent posteriad; PW: EW = 1.24; neck one third as wide as head at posterior angles; posterior angles shortly rounded; posterior margin slightly convex; setiferous punctation sparse; on vertex, four setiferous punctures in convergent line adjacent to impunctate midline; laterad two additional supraocular lines of setiferous punctures; temples and posterior margin more densely punctate; without microsculpture; surface polished.

Antennae slightly longer than head; first antennomere elongate; slightly longer than two following antennomeres; conical second and third antennomere elongate; approximately twice as long as apical width; fourth antennomere slightly longer than wide; width of following antennomeres slightly increasing; fifth antennomere slightly wider than long; tenth antennomere 1.5 times as wide as long; all antennomeres pubescent with apical setae.

Pronotum: 0.48 mm long, 0.39 mm wide; sides nearly parallel; anterior angles widely rounded; anterior margin semi-circular; posterior angles shortly rounded; lateral margin fine; in dorsal aspect, visible in posterior half; setiferous punctation sparse; along wide impunctate midline three pairs of setiferous punctures; interstice between anterior pair twice as wide as interstices between two posterior pairs; few additional punctures laterad; several punctures with long setae along lateral margin; without microsculpture; surface polished.

Elytra: 0.51 mm long, 0.54 mm wide; sides slightly divergent to posterior angles; at posterior angles 1.3 times as wide as at shoulders; shoulders obtuse; posterior margin triangularly emarginate; setiferous punctation in irregular lines of fife to six punctures; three lines on disc; additional line along lateral margin.

Abdomen densely pubescent.

Aedeagus moderately broad; seminal vesical half as long as central lobe; basal inner duct looped; ending in funnel-like widening; apical inner duct shortly coiled; paramere slender; slightly shorter than central lobe; slightly widened at apex to small circular plate; at apex with four long setae; three sensillae at central shaft.

Spermatheca: 0.21 mm long, 0.12 mm wide; bursa copulatrix in asymmetric position to coiled duct; coiled duct with few irregular coils.

Etymology: The species name derived from the same Latin word meaning three colours and refers to the threecoloured fore-body.


Field Museum of Natural History