Diochus mexicanus, 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 : 23-24

Diochus mexicanus spec. nov.

urn:lsid:zoobank.org:act:10213825-70EC-4B7F-BE1A-4FFD11B5D988

Figs 24A–C , 39J , 43G

Type material: male, Holotype: Mexico: Veracruz, Fortin ,

5.8.1969, leg. S. & J. Peck ( AMNH).

Paratypes: 10 males, 14 females with same data as holotype (22 AMNH, 2 UIC); Veracruz, Balzapote, Berlese , rain forest leaf litter , 2 males, 2 females, 7.8.1976, leg. A. Newton ( FMNH) ; 6 mi NE Catemaco , 1500 ft. elev., Berlese, rain forest leaf litter, female, 7.7.1976, leg. A. Newton ( FMNH) .

Diagnosis: Closely related to D. brooksi regarding the structures of the paramere and the shape of the head. It can be separated from D. brooksi by the shorter elytra. Whereas elytra are nearly quadrate in D. brooksi , they are distinctly wider (1.2 times) than long in D. mexicanus . Both species are differentiated from D. ecuadoriensis by the wider head. The head is 1.1 times longer than wide (PW: EW = 1.24 in D. brooksi resp. 1.12 in D. mexicanus ), whereas it is 1.4 times longer than wide in D. ecuadoriensis (PW: EW = 1.07).

Description: Length: 3.5 mm. Colouration: dark brown; pronotum slightly lighter brown; legs and antennae light brown to yellowish brown; first three antennomeres lighter brown than following antennomeres.

Head: 0.49 mm long, 0.43 mm wide; moderately long eyes not prominent; EL: HL = 0.20; temples more than 3 times longer than eyes; distinctly divergent posteriad; PW: EW = 1.24; setiferous punctation moderately deep and dense; adjacent to impunctate midline with posteriorly convergent line of punctures; between inner line and eyes with supraocular line of 7 punctures; more setiferous punctures on postocular area; netlike microsculpture moderately deep; on vertex elongate meshes transversely striate.

Antennae as long as head and half of pronotum combined; first antennomere longer and slightly thicker than second antennomere; second and third antennomere conical; twice as long as apical width of antennomeres; following antennomeres approximately rectangular; fourth quadrate; tenth nearly 1.5 times wider than long; all antennomeres pubescent; basal antennomeres with setae.

Pronotum: 0.62 mm long, 0.52 mm wide; sides nearly parallel; anterior third semi-circular; posterior angles widely rounded; lateral margin fine; in dorsal aspect, visible in posterior third; setiferous punctation sparse; along impunctate midline with three pairs of punctures; interstice between anterior pair of punctures 2.5 times as wide as between posterior pairs of punctures; laterad few more setiferous punctures; along lateral margin with several setiferous punctures; between setiferous punctation with sparse micro-punctation; without microsculpture; surface polished.

Elytra 0.52 mm long, 0.62 mm wide; sides slightly divergent to posterior angles; shoulders obtuse; posterior angles rectangular; posterior margin emarginate; setiferous punctation moderately deep and dense; in irregular rows; inner row adjacent to suture line; laterad on disc two more lines with four to five punctures; ground sculpture slightly coriaceous; surface slightly shiny.

Abdomen densely pubescent.

Aedeagus elongate; seminal vesical of endophallus slender; 0.6 times as long as central lobe; basal inner duct looped; ending in several sclerotised appendices; at apex with sclerotised hooks; paramere slender; sinuate with slightly widened apex; at apex with three long setae; at basal shaft with few sensillae.

Spermatheca approximately circular; 0.35 mm in diameter; bursa copulatrix in lateral position to irregularly coiled duct.

Etymology: The species name refers to the country,

where it was found.

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 22–25:Diochus maculicollisgroup:ofD. maculicollis(22),D. peruvianus(23),D. mexicanus(24),D. pumilio (25);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.