Diochus brunneus, 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 : 28-29

Diochus brunneus spec. nov.

urn:lsid:zoobank.org:act:7B393143-5E9A-4DE2-92D7-4458FAEF5B2B

Figs 30A–C , 40B , 44D

Type material: male, Holotype: Costa Rica: Cartago Province, W Cachi, S-side, Cachi lake (9°48.47'-49.20'N, 83°48.42'-50.33'W), 1010–1040 m elevation, road along lake shore, secondary forest, coffee plant., gardens, car net, 6.12.2013, leg. M. Schülke & B. Grünberg ( MSC).

Paratypes: 2 females same location, date and collectors as holotype , 2 males from same location and collectors as holotype, but 7.12.2013 (2 MSC, 2 UIC); Panama: Colon, Parque Nac. Soberania, Pipeline Rd. km 2.0 (9°07'N, 79°45'W), 40 m elevation, collected by flight intercept rap, male, 29.– 31.5.1995, leg. J. Ashe, #084 ( KNHM) .

Diagnosis: Within the species group, D. brunneus is characterised by its dark brown colouration with lighter brown anterior half of pronotum. However, the main character to identify the species is the shape of the paramere with the long asymmetric apical process. A bicoloured pronotum is also found in D. hibbsi of the Diochus inornatus-group. D. hibbsi is considerably larger than D. brunneus , and the pronotum has a light brown posterior half, whereas the pronotum of D. brunneus has a light brown anterior half.

Description: Length: 4.0 mm. Colouration: dark brown; anterior half of pronotum, posterior margin of elytra, posterior half of abdominal segment VIII, and legs light brown; basal antennomeres and apex of eleventh antennomere light brown.

Head: 0.57 mm long, 0.48 mm wide; eyes slightly prominent; large; temples twice as long as eyes; EL: HL = 0.29; temples slightly divergent posteriad; PW: EW 1.26; posterior angles widely rounded to slightly curved posterior margin; setiferous punctures deep; along impunctate midline with irregular row of four setiferous punctures; convergent posteriad; on clypeus few punctures between the medial rows; second supraocular row posteriad convergent; ending at middle of vertex; postocular area with denser setiferous punctation; very weak diagonally striate microsculpture; surface slightly shiny.

Antennae as long as head and half of pronotum combined; slightly thicker and longer than following antennomeres; second conical antennomere 0.7 times as long as first; more than twice as long as its apical width; third antennomere equal in length and width as second; length of following antennomeres decreasing; fourth antennomere slightly longer than wide; tenth slightly wider than long; all antennomeres pubescent and with few apical setae.

Pronotum: 0.75 mm long, 0.64 mm wide; widest in posterior half; sides slightly convergent to anterior margin; anterior angles widely rounded; anterior margin nearly semi-circular; posterior angles shortly rounded; lateral margin fine; in dorsal aspect, visible in posterior half; setiferous punctures sparse and as deep as on head; along impunctate midline, three pairs of punctures convergent posteriad; interstice between first pair three times as wide as between posterior pair; interstice of intermediate pair intermediately wide; between this row and lateral margin three to four more punctures in irregular row; more setiferous punctures along lateral margin; without microsculpture; surface polished.

Elytra: 0.75 mm long, 0.77 mm wide; sides slightly divergent posteriad; shoulders obtusely angulate; posterior angles nearly rectangular; posterior margin with slightly triangular emargination; setiferous punctation in irregular rows; inner row of five to six punctures adjacent to suture line; two more rows on disc; along lateral margin several setiferous punctures; weak coriaceous ground sculpture; surface less shiny than pronotum.

Abdomen densely pubescent.

Aedeagus elongate; seminal vesical of endophallus slen- der; 0.56 times as long as total length of central lobe; basal inner duct looped ending in sclerotised forceps; paramere broad; in apical half folded in one transparent lobe and one more sclerotised lobe; obtusely angulate in apical third; transparent apical lobe triangularly elongate; at angle with two long setae; at apex with one slightly shorter seta.

Spermatheca 0.47 mm long, 0.29 mm wide; bursa copulatrix in lateral position to coiled duct; coiled duct divided into approximately circular part and coiled connection to bursa copulatrix; circular part with numerous partly irregular coils; connection to bursa copulatrix with irregular coils.

Etymology: The species name derived from the same Latin word meaning brown and describes the dark brown colouration.

Figures

Figs 44: Fore-bodies of Diochus pumilio (A), D. panamaensis (B), D. angustiformis (C), D. brunneus (D), D. schaumii (E), D. argen-

Figs 30–33: Diochus schaumii-group: D. brunneus (30), D. curtipennis (31), and Diochus verhaaghi-group: D. verhaaghi (32), D. santacatarinae (33); aedeagus (A), paramere (B) and antenna (C); scale bar: A, B: 0.1 mm, C: 0.2 mm.

Fig. 40: Spermatheca of Diochus schaumii-group: Diochus argentinae (A), D. brunneus (B), D. curtipennis (C), D. schaumii (D), D. verhaaghi-group: D. verhaaghi (E), D. santacatarinae (F), D. nanus-group: D. perplexus (G), D. parvulus (H), D. nanus (I), D. apicipennis (J), D. formicetorum (K); scale bar: 0.1 mm.