Diochus plaumanni, 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 : 16

Diochus plaumanni spec. nov.

urn:lsid:zoobank.org:act:4169DC68-8683-4290-A14A-62492505A4CA

Figs 18A–C , 39B , 42E

Type material: male, Holotype: Argentina: Prov., P.N. Chaco, 100 km NW Restistencia , subtropical thorn forest, rotten logs & sticks with fungus, sifted, 15.12.1990, leg. S. & J. Peck ( FMNH).

Paratypes: Argentina: Misiones Prov., P.N. Iguazu, TV tower road, log & bark litter, female, 2.1.1991, leg. S. & J. Peck ( FMNH) ; same location, subtropical forest, treebase litter, 200 m elev. 2 females, 24.12.1990, leg. S. & J. Peck ( FMNH) ; 20 km SE P. Iguazu , Araucaria plantation treebase litter, female, 24.12.1990, leg. S. & J. Peck ( FMNH) ; same location, Salto Macuco , moss & log bark, female, 26.12.1990, leg. S. & J. Peck ( FMNH) ; 20 km SE Puerto Iguazu , forest, treebase litter, male, 31.12.1990, leg. S. & J. Peck ( FMNH) ; Chaco Prov., P.N. Chaco, 100 km NW Restistencia , rotten logs & sticks with fungus, 1 male, 1 female, 14.12.1990, leg. S. & J. Peck ( FMNH) ; same location, seasonal subtropical thorn forest, sifted rotted logs, leaf litter, treebase litter, 2 males, 3 females, 14.12.1990, leg. S. & J. Peck (4 FMNH, 1 UIC) ; same location and habitat, 1 male, 1 female, 13.12.1990, leg. S. & J. Peck ( FMNH) ; Paraguay: Villa Rica, sifted, Auraucaria forest , 1 male, 1 female, 10.2.1924, leg. F. Schade ( NMW) ; Brazil: Est. Santa Catarina, Nova Teutonia (52°23'W, 27°11'S), 7 females, 3.1954, leg. F. Plaumann (6 FMNH, 1 UIC) ; same location, 2 males, 7 females, 8.1953, leg. F. Plaumann ( FMNH) ; Minas Gerais, Paso Quatro , 1 male, leg. Reichensperger ( NMW) .

Diagnosis: Regarding the structure of the paramere, D. plaumanni is closely related to D. hermani . In both species a short apical apendix is found at the paramere. In D. plaumanni , the apendix is slightly more curved than in D. hermani and the subapical prominence is absent. Moreover, D. hermani has four equally long apical setae, whereas D. plaumanni has only three uneqally long setae. D. hermani is significantly larger, the antennae are more elongate and the head is more parallel than in D. plaumanni ( D. hermani: PW : EW = 1.21, D. plaumanni: PW : EW = 1.17).

Description: Length: 3.8 mm. Colouration: light brown; head and anterior segments of abdomen slightly darker; antennomeres four to eleven darker than basal three antennomeres.

Head: 0.57 mm long, 0.45 mm wide; eyes small; EL: HL = 0.20, temples slightly divergent posteriad; PW: EW = 1.17; posterior angles widely rounded; posterior margin nearly semi-circular; setiferous punctation deep and dense; with wide impunctate midline; on supraocular and postocular area, interstices between punctures approximately as wide as diameter of punctures; microsculpture nearly absent, but on restricted areas with remains of extremely weak microsculpture.

Antennae as long as head and half of pronotum combined; first antennomere thicker and one third longer than second antennomere; second and third antennomere conical; twice as long as apical width; antennomeres four and five approximately quadrate; following antennomeres wider than long; eighth antennomere approximately 1.5 times as wide as long; all antennomeres with short apical setae and pubescent.

Pronotum: 0.68 mm long, 0.51 mm wide; sides parallel; in anterior third widely rounded to neck; posterior angles shortly rounded; obtuse; lateral margin fine; in dorsal aspect, visible in posterior half; setiferous punctation sparse; with wide impunctate midline; along midline four pairs of punctures in irregular position; laterad with few additional punctures; along lateral margin few setiferous punctures; between setiferous punctation with sparse micro-punctures; without microsculpture; surface polished.

Elytra: 0.57 mm long, 0.67 mm wide; sides slightly divergent from shoulders to posterior angles; shoulders shortly rounded; posterior angles nearly rectangular; posterior margin slightly emarginate; setiferous punctation in irregular rows of five to six punctures; with weak ground sculpture; surface less shiny than pronotum.

Abdomen with dense pubescence.

Aedeagus moderately slender; seminal vesical of endophallus thick; 0.7 times as long as total length of central lobe; basal inner duct looped; ending in wide funnel with apical forceps; continued to shortly coiled apically duct; at apex with hook-like sclerotised structures; parameres as long as central lobe; slender; at apex with recurved hook-like process; at apex of process two long setae and in short distance another shorter seta; at middle of shaft with two sensillae.

Spermatheca 0.47 mm long, 0.24 mm wide; bursa copulatrix placed inside coiled duct in symmetrical position.

Etymology: The species name honours Fritz Plaumann, who intensively collected Staphylinidae in southern Brazil during the mid of the 20 th century.

Figures

Figs 42: Fore-bodies of Diochus antennalis (A), D. tricolor (B), D. amazonensis (C), D. hermani (D), D. plaumanni (E), D. hibbsi (F), D. newtoni (G), D. novus (H); scale bar: 0.5 mm.

Figs 18–21: Diochus inornatus-group: D. plaumanni (18), D. newtoni (19) and Diochus maculicollis-group: D. brooksi (20), D. ecuadoriensis (21); aedeagus (A), paramere (B) and antenna (C); scale bar: A, B: 0.1 mm, C: 0.2 mm.

Fig. 39: Spermathecae of Diochus inornatus-group: D. schuelkei (A), D. plaumanni (B), D. tricolor (C), D. vicinus (D); Diochus maculicollis-group: D. brooksi (E), D. ecuadoriensis (F), D. maculicollis (G), D. pumilio (H), D. peruvianus (I), D. mexicanus (J), D. panamaensis (K); Diochus schaumii-group: D. angustiformis (L); scale bar: 0.1 mm.