Diochus unicolor, 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 : 8-9

Diochus unicolor spec. nov.

urn:lsid:zoobank.org:act:5D7AB086-BCE1-4FEF-A732-1E210D4B3A87

Figs 7A–C , 38E , 41F

Type material: male Holotype: Suriname: Para, Cardina creek , 11 km SE Zanderij Airport (55°09.29'W, 5°23.36'N), 30 m elevation, collected by flight intercept trap, 19.–20.6.199, leg. Z.H. Falin & A. Gangadin, #SUR1F99 088 ( KNHM).

Paratypes: Panama: Canal Zone, Frijoles train stop, sifted, leaf litter, male, 25.10.1975, leg. D.S. Chandler ( FMNH) ; Bolivia: Beni , Ilha Flores, Rio Iténez , 1 male, 3 females, 7.8.1964, leg. J.K. Bouseman & L. Lussenhop ( AMNH) ; Santa Cruz , 10 mi W Puerto Chuelo, UV light trap, male, 27.3.1978, leg. Marshall ( FMNH) ; Brazil: Goias, Sta. Isabel, R. Araguaia , Isla Bananal , at light, female, 27.10.– 4.11.1960, leg. B. Malkin ( FMNH) ; Paraguay: Paraguari, Sapucai (25°40'S, 56°55'W), 190 m elevation, male, 1.– 3.4.1994, leg. U. Drechsel ( UIC) ; Dep. Central, San Lorenzo (25°20'S, 57°31'W), female, 9.2.1991, leg. U. Drechsel ( KNHM) ; Villarrica, female, April , 1933, leg. Koller ( NMW) .

Diagnosis: Regarding the small size, D. unicolor resembles D. ashei and D. adisi of this group. It is mainly separated from these two species by the shorter eyes. EL: HL is only 0.21, wheres it is both 0.29 and 0.27 in D. ashei and D. adisi , respectively.

Description: Length: 3.0 mm. Colouration: light brown to yellow; head slightly darker brown; legs and antennae light yellow.

Head 0.41 mm long, 0.38 mm wide; eyes prominent; temples 2.6 times as long as eyes; EL: HL = 0.21; distinctly divergent to posterior angles; PW: EW = 1.22; posterior angles shortly rounded to approximately straight posterior margin; setiferous punctation moderately dense; narrow midline impunctate; along midline, irregular row of four setiferous punctures; supraocular area with irregular setiferous punctation; temples more densely punctate; clypeus without microsculpture; surface polished; vertex with distinct transversely striate microsculpture; slightly shiny.

Antennae as long as head and pronotum combined; first antennomere thicker than following antennomeres; triangular second antennomere more than twice as long as at apical width; conical third antennomere twice as long as apical width; length of following antennomeres decreasing; fourth antennomere slightly longer than wide; tenth antennomere quadrate; all antennomeres pubescent and with apical setae.

Pronotum 0.56 mm long, 0.42 mm wide; widest in anterior half; widely rounded in nearly semi-circular curve; posteriad slightly convergent to shortly rounded posterior angles; posterior margin straight; lateral margin fine; in dorsal aspect, visible in posterior half; setiferous punctation moderately dense; along impunctate midline with three pairs of setiferous punctures; interstice between anterior pair of punctures three times as wide as between posterior pairs of punctures; laterad four to five setiferous punctures; along lateral margin several setiferous punctures.

Elytra 0.53 mm long, 0.53 mm wide; sides slightly divergent to posterior margin; shoulders obtusely angulate; posterior margin deeply emarginate; emargination triangular; setiferous punctation in irregular rows; inner row of five punctures adjacent to suture line; two additional rows on disc; ground sculpture weakly coriaceous; surface slightly shiny.

Abdomen densely pubescent.

Aedeagus short and broad; seminal vesical of endophallus thick and oval; approximately half as long as total length of central lobe; inner basal duct looped; continued to coiled apical duct; paramere slender; with four long apical setae; without sensillae at shaft.

Spermatheca 0.37 mm long, 0.24 mm wide; oval; bursa copulatrix approximately in central position of coiled duct.

Etymology: The species name derives from the same Latin word meaning only one colour and refers to the light brown to yellowish colouration without any distinct darker parts.

Figures

Figs 41: Fore-bodies of Diochus longicornis (A), D. tarsalis (B), D. adisi (C), D. ashei (D), D. guianensis (E), D. unicolor (F), D. inornatus (G), D. hanagarthi (H); scale bar: 0.5 mm.

Figs 6–9: Diochus longicornis-group: Diochus ashei (6), D. unicolor (7); Diochus inornatus-group: D. inornatus (8), D. hanagarthi (9); aedeagus (A), paramere (B) and antenna (C); scale bar: A, B: 0.1 mm, C: 0.2 mm.

Fig. 38: Spermathecae of Diochus longicornis-group: D. longicornis (A), D. tarsalis (B), D. ashei (C), D. guianensis (D), D. unicolor (E); Diochus inornatus-group: D. inornatus (F), D. hanagarthi (G), D. antennalis (lateral aspect H), D. hermani (I), D. hibbsi (J), D. newtoni (K), D. novus (L); scale bar: 0.1 mm.