Diochus apicipennis CAMERON, 1922

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 : 35

Diochus apicipennis CAMERON, 1922

Figs 37A–C , 40J , 45E

Diochus apicipennis CAMERON, 1922: 116

Type material examined: Syntypes: Saint Vincent: W.I., male, aedeagus lost, female, leg. H.H. Smith, #94, #151 ( BMNH) .

Additional material examined: Saint Vincent: Leeward side, male, leg. H.H. Smith ( NMW) ; Guadeloupe: Gourbyre , Acc. 4860, 4 males, 14 females, without more data (16 AMNH, 2 UIC) .

Diagnosis: The four species of the D. nanus-group are very similar and hardly to distinguish without section of the aedeagus. The eyes of D. apicipennis are slightly shorter than in the other three species with EL: HL ratio of 0.21 (0.28 in the other species). The species can be clearly distinguished from the other three species by the structure of the paramere. Whereas the apical margin of the widened plate of the paramere is convex, the margin is distinctly emarginate and separated into two lobes in the three other species.

Description: Length: 2.8 mm. Colouration: yellow; posterior third of elytra brown; abdomen dark yellow to brownish; legs and antennae light yellow; antennomeres four to ten slightly darker.

Head: 0.41 mm long, 0.38 mm wide; eyes not prominent; small; EL: HL = 0.21; temples distinctly divergent posteriad; PW: AW 1.23; setiferous punctation moderately deep and dense; adjacent to wide impunctate midline with line of three punctures; between medial line and eyes another convergent line of five to six punctures; temples sparsely punctate; without microsculpture; surface polished.

Antennae as long as head and half of pronotum combined; first antennomere slightly thicker than following antennomeres; second and third antennomere conical; nearly twice as long as its apical width; following antennomeres increasing in width; fourth antennomere quadrate; tenth antennomere nearly twice as wide as long; all antennomeres pubescent; basal three antennomeres with short setae.

Pronotum: 0.47 mm long, 0.41 mm wide; parallel; anterior third nearly semi-circular; posterior angles obtusely rounded; lateral margin fine; in dorsal aspect, visible in posterior third; setiferous punctation sparse; adjacent to wide impunctate midline with row of three punctures; interstice between anterior pair more than twice as wide as between posterior pairs; few setiferous punctures laterad; along lateral margin several setiferous punctures; without microsculpture; surface polished.

Elytra: 0.50 mm long, 0.53 mm wide; sides slightly divergent to posterior angles; shoulders obtusely rounded; posterior angles nearly rectangular; setiferous punctation moderately deep and dense; in irregular rows; first row adjacent to suture line with eight punctures; laterad three additional rows of five to six punctures; without microsculpture, but weak coriaceous ground-sculpture; surface less shiny than that of head and pronotum.

Abdomen densely pubescent.

Aedeagus with moderately thick; seminal vesical of endophallus 0.7 times as long as total length of central lobe; basal inner duct looped; ending into sclerotised forceps; apically with sclerotised hooks; paramere with slender shaft; anterior half widened to uniform plate; plate at one side with transparent lobe; at apical margin of plate, one long seta and two setae (one long and one short) at opposite angles; several sensillae along margin from widened part to basal shaft.

Spermatheca 0.28 mm long, 0.22 mm wide; bursa copulatrix in lateral position to coiled approximately circular duct; duct irregularly coiled with few coils.

Figures

Figs 45: Fore-bodies of Diochus santacatarinae (A), D. perplexus (B), D. parvulus (C), D. nanus (D), D. apicipennis (E), D. formicetorum (F); scale bar: 0.5 mm.

Figs 34–37: Diochus nanus-group, Diochus perplexus (34), D. nanus (35), D. parvulus (36), D. apicipennis (37); aedeagus (A),

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.