Diochus vicinus SHARP, 1876

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 : 19-20

Diochus vicinus SHARP, 1876

Figs 10A–C , 39D , 43C

Diochus vicinus SHARP, 1876: 185

Diochus flavicans SHARP, 1876: 185 new synonymy

Type material examined: 1 female, Brazil: Pará , Tapajos ( BMNH) ; 2 female syntypes of D. flavicans , Brazil: Pará , Tapajos ( BMNH) .

Further material examined: Colombia: Vichada, PNN El Tuparro, Cerro Tomás (67°51'W, 5°21'N), 140 m elev., Malaise trap, male, 22.5.– 3.6.2001, leg. I. Gill ( KNHM) ; Brazil: Amazonas, Ilha de Marchanteria (59°58'W, 3°15'S), Varzéa , floating meadow, 3 males, 16.2.1982, 22.1.1982, leg. J. Adis ( UIC) ; Ilha Muratú (60°21'W, 3°34'S), 2 females, 25.2.1975, leg. U. Irmler ( UIC) ; Roraima, mouth of Rio Branco, Lago Adauaú (61°51'W, 1°19'S), male, 22.8.1971, leg. U. Irmler ( UIC) ; Pará , 5 km E Belém, soil litter layer, in primary terra firme forest, male, 30.5.1973, leg. R.T. Schuh ( AMNH) ; IPEAN, from litter in “ Mocambo ”, male, 3.7.1973, leg. R.T. Schuh ( AMNH) ; Mato Grosso, Barra de Tapirapé , at light, 4 males, 1 female, 15.12.1960, leg. B. Malkin ( FMNH) ; male, same location, same collector, but 1.– 11.1.1963 ( FMNH) ; Peru: Loreto, Lake Yarinachocha , 10 km NW Pucallpa, 150 m elev., collected at light, male, 27.12.1971, leg. R.T. Schuh ( AMNH) ; Madre de Dios, Tambopata , male, 26.10.1982, leg. L.E. Watrous, G. Mazurek ( FMNH) .

Diagnosis: In size, colouration and length of antennae, D. vicinus resembles D. inornatus and D. hanagarthi . The EL: HL is 0.24, slightly shorter than in D. hanagarthi , separates both species from D. inornatus with longer temples (EL: HL = 0.21). Moreover, the antennae are slightly longer than in D. hanagarthi and D. inornatus . The species can be easily separated from the other Diochus species by the elongate hooked apical process of the paramere. Unfortunately, the two syntypes of D. flavicans are females. As I found no significant differences to

D. vicinus , D. flavicans is synonymised to D. vicinus .

Description: Length: 4.3 mm. Colouration: head and pronotum totally yellow-brown; elytra light brown with dark transverse spot in anterior half on each side of suture; abdomen darker than fore-body, but posterior margin of segments as light elytra; legs yellow; antennomeres 1, 2, and 11 yellow; antennomeres 4–10 darker, brown.

Head: 0.46 mm long, 0.40 mm wide; eyes slightly prominent; moderately large; temples 2.5 times as long as eyes; EL: HL = 0.24; temples slightly divergent posteriad; PW: EW 1.14; posterior angles nearly rectangular; sharply rounded; clypeus widely rounded; neck one third as wide as head; inter-ocular space and clypeus densely and deeply punctate; wide midline impunctate; on average, interstice between punctures as wide as or slightly shorter than diameter of setiferous punctures; on average, setae distinctly longer than interstices; on vertex sparsely punctate; large area without punctures; laterad densely punctate; surface without microsculpture; shiny.

Antennae slightly longer than head and half of pronotum combined; first to third antennomere distinctly longer than following antennomeres; nearly twice as long as wide; fourth to eleventh antennomeres approximately quadrate; first antennomere with long thick setae; fourth to eleventh antennomere pubescent;.

Pronotum: 0.54 mm long, 0.49 mm wide; widest close to posterior margin; slightly narrowed to anterior margin, but nearly parallel; posterior and anterior angles widely rounded; sides finely margined; in dorsal aspect, margin covered in anterior half; setiferous punctures large, but sparse; on average, interstices between punctures twice as wide as diameter of punctures; on each side of impunctate midline with 3–4 setiferous punctures in longitudinal line; without microsculpture, but indistinct extremely weak ground sculpture; surface shiny.

Elytra: 0.67 mm long, 0.67 mm wide; sides divergent to posterior margin; posterior angles and shoulders widely rounded; shoulders obtuse; setiferous punctures in longitudinal lines; setae pointing posteriad; interstices between punctures of lines and between lines at least two to three times as wide as diameter of punctures; surface with indistinct weak ground sculpture; shiny.

Abdomen densely pubescent and matt in contrast to fore-body.

Aedeagus with seminal vesical slightly longer than half of total length of central lobe; basal inner duct looped; apical inner duct with large coil; paramere narrow at base; slightly widened to apex; not projecting apex of central lobe; with long asymmetric acute process at apex with short apical hook.

Spermatheca 0.47 mm long, 0.21 mm wide; bursa copulatrix in central position of coiled oval duct; coiled duct widest in anterior half; narrowed at middle and slightly widened in posterior half.

Figures

Figs 43: Fore-bodies of Diochus schuelkei (A), D. tricolor (B), D. vicinus (C), D. brooksi (D), D. ecuadoriensis E), D. maculicollis (F), D. mexicanus (G), D. peruvianus (H); scale bar: 0.5 mm.

Figs 10–13: Diochus inornatus-group: of D. vicinus (10), D. antennalis (11), D. novus (12), D. tricolor (13); aedeagus (A),

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.