Diochus novus, 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 : 15

publication ID

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

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scientific name

Diochus novus


Diochus novus spec. nov.


Figs 12A–C View Figs 10–13 , 38L View Fig , 42H View Figs 42

Type material: male, Holotype: Brazil: Pará, Jacareacanga, 10.1959, leg. M. Alvarenga ( INPA).

Paratypes: Brazil: Santa Catarina, without more details, 1 male, leg. P.E. Klimsch ( NMW) ; Mato Grosso, Primavera do Leste , Ilha Grande farm (54°14.6'W, 15°26.6'S), Cerrado forest , litter, male, 8.4.2014, leg. K. Peña Peña ( UIC) GoogleMaps ; Campo Verde, Rio Engano farm (54°50.7'W, 15°23'S), Cerrado forest , litter, female, 14.3.2014, leg. K. Peña Peña ( UIC) GoogleMaps ; Pará, Ipean , litter in “Mocambo”, 1 male, 1 female, 2.7.1973, leg. R.T. Schuh ( AMNH) ; Belém, Ipean , primary terra firme forest, plot #4, female, 6.6.1973, leg. R.T. Schuh ( AMNH) ; Rio de Janeiro , female, leg. Squires, Sharp coll. #1905-313 ( BMNH) ; Bolivia: Dept. Beni, Prov. Vaca Diez , 2 km NW Tumichucua, forest, leaf litter in sunken area, 1 male, 3 females, 12.8.1990, leg. P. Parillo ( FMNH) .

Diagnosis: Among the species of the group, D. novus resembles D. hanagarthi and D. inornatus in size and colouration. It is slightly shorter than the two species. The eye length is similar to that of D. inornatus and, thus, shorter than in D. hanagarthi . In contrast, the slightly posteriorly divergent head is similar to D. hanagarthi and different from the parallel head of D. inornatus . However, it is mainly differentiated by the characteristic aedeagus with the paramere longer than the central lobe and the long hook-like apex.

Description: Length 3.6 mm. Colouration: dark brown; pronotum slightly lighter, but still dark; legs and antennae yellow with antennomeres four to eleven dark yellow to light brown.

Head: 0.51 mm long, 0.42 mm wide; eyes small, not prominent; temples three times as long as eyes; EL: HL = 0.21; temples moderately divergent posteriad; PW: EW = 1.19; posterior angles widely rounded; wide midline impunctate; adjacent to midline in anterior two third with row of four setiferous punctures; laterad to medial row of punctures irregular setiferous punctation; postocular area and along posterior margin more setiferous punctures; on small parts with extremely weak microsculpture; remaining parts polished; surface shiny.

Antennae as long as head and half of pronotum combined; first antennomere slightly thicker than following antennomeres; following antennomeres decreasing in length; conical second and third antennomeres one third shorter than first antennomere; fourth antennomere still longer than wide; fifth quadrate; following antennomeres slightly wider than long; all antennomeres pubescent; basal antennomeres with few apical long setae.

Pronotum: 0.60 mm long, 0.52 mm wide; slightly divergent from anterior to posterior angles; anterior angles widely rounded; posterior angles indistinct; obtuse; lateral margin fine; in dorsal aspect, visible only in posterior third; setiferous punctation moderately deep; sparse; along impunctate midline with row of three pairs of punctures; interstice between anterior pair of punctures more than twice as wide than interstices between posterior pairs; laterad, few irregularly placed setiferous punctures; along lateral margin several punctures with long setae; without microsculpture; surface polished.

Elytra: 0.63 mm long, 0.65 mm wide; sides slightly divergent to posterior margin; shoulders shortly rounded; posterior margin triangularly emarginate; setiferous punctation in irregular longitudinal lines; first line adjacent to suture with seven to eight punctures; with weak coriaceous ground sculpture; surface shiny.

Abdomen densely pubescent.

Aedeagus with seminal vesical of endophallus slightly longer than half of length of central lobe; basal inner duct looped; ending in broad dark sclerotised apex; continued in widely coiled apical duct; paramere projecting central lobe; narrow shaft suddenly widened near apex to hooklike expansion; apex with four long setae at outer side; few sensillae on basal part of shaft.

Spermatheca 0.39 mm long, 0.18 mm wide; bursa copulatrix in asymmetric position to coiled duct; coiled duct oval; slightly narrower at middle than at both ends.

Etymology: The Latin word novus means new and refers to the fact that the species is new to science.


Instituto Nacional de Pesquisas da Amazonia


Naturhistorisches Museum, Wien


American Museum of Natural History


Field Museum of Natural History