Diochus guizhouensis Shuai, Nozaki & Tang, 2021

Shuai, Qi, Nozaki, Tsubasa & Tang, Liang, 2021, Notes on the genus Diochus Erichson, with descriptions of two new species from China (Coleoptera, Staphylinidae), Zootaxa 4908 (2), pp. 276-282 : 280

2. Diochus guizhouensis Shuai, Nozaki & Tang , new species

( Figs 2 , 16–22 )

Type material. Holotype. China: Guizhou: ♁, glued on a card with labels as follows: “ China: Guizhou Province, Libo county , Maolan N. R., Bizuo , 25°16’59’’N, 108°03’18’’E, 587m, mixed leaf litter, sifted, 28.IV.2017, Jiang, Jiang, Hu, Liu & Zhang leg. ” “ Holotype / Diochus guizhouensis / Shuai, Nozaki & Tang” [red handwritten label] ( SHNU) . Paratypes. 1♁, same data as for the holotype ( SHNU); 1♀ , Libo county , Maolan N. R ., Bizuo , 25°17’16’’N, 108°04’18’’E, 478–507m, mixed leaf litter, sifted, 26.IV.2017, Jiang, Jiang, Hu, Liu & Zhang leg. ( SHNU) .

Description. Body dark brown, head and elytra slightly darker, portions along the posterior margins of abdominal segments lighter, appendages reddish yellow with antennal segments 4–8 slightly darker.

BL: 5.9–6.1 mm, FL: 2.9–3.0 mm. HL: 0.78–0.81 mm, HW: 0.60–0.62 mm, EyL: 0.16–0.22 mm, TL: 0.46–0.48 mm, PL: 0.99–1.07 mm, PW: 0.83–0.87 mm, EL: 1.01–1.03 mm, EW: 1.07–1.09 mm, SL: 0.68–0.69 mm.

Head 1.27–1.31 times as long as wide, tempora slightly widened posterad, posterior angles rounded, eyes 0.38–0.50 times as long as tempora. Dorsal surface shiny, microsculpture distinct and transverse, punctation coarse and sparse. Mandibles ( Fig. 19 ) falciform, each with a large tooth and a small tooth on inner margin. Antennae slender, antennomere 3 distinctly longer than 2 (ratio: 1.18–1.25). Gular sutures confluent at about basal 1/4, then extended to base.

Pronotum 1.20–1.23 times as long as wide, wider than head, lateral margins widened posteriad to basal 1/3, then convergent backwards, anterior and posterior angles broadly rounded. Dorsal surface shiny without microsculpture. Disc with one row of punctures composing of 3 or 4 large punctures on each side of the midline and 1 or 2 additional punctures outside of each row of punctures.

Elytra 0.93–0.95 times as long as wide, shorter than pronotum at suture, lateral margins divergent posteriad, dorsal surface shiny without microsculpture; each elytron with a row of 5 punctures near suture and a row of 5 punctures in median row.

First four segments of protarsi moderately dilated in both sexes.

Abdomen with dense and fine punctation and with distinct microsculpture, posterior margin of tergite VII with distinct palisade fringe.

Male. Head with a small round elevation between the eyes; sternite VIII ( Fig. 21 ) with posterior margin emarginated at middle; sternite IX ( Fig. 20 ) symmetrical, widest near the middle; aedeagus ( Figs 16–18 ) with parameres as long as 1/3 length of the median lobe, internal structures sclerotized, consisting of paired apical sclerites and a single Y-shaped basal plate.

Female. Head without a small spot elevation between eyes; sternite VIII with posterior margin rounded; spermatheca ( Fig. 22 ) sclerotized, very long, with three bends.

Distribution. China (Guizhou).

Remarks. The new species is similar to D. japonicus Cameron, 1930 in appearance, but can be distinguished from the latter by male frons with a small round elevation between the eyes, male sternite VIII without coarse setae and different morphology of aedeagus and spermatheca.

Etymology. The specific name is derived from the locality, Guizhou, of the species.

Figures

FIGURES 1–3. Habitus. 1—Diochus japonicus; 2—D. guizhouensis; 3—D. caudapiscis. Scale bars: 1 mm.

FIGURES 16–29. Sexual characters. 16–22—Diochus guizhouensis; 23–29—D. caudapiscis; 16, 18, 23—aedeagus in dorsal view; 17, 24, 25—aedeagus in ventral view; 19, 26—mandibles; 20, 27—male sternite IX; 21, 28—male sternite VIII; 22, 29—spermatheca. Scale bars: 0.25 mm.