Tachinus (Tachinoderus) bilobus Chang, Li & Yin, 2019

Chang, Yuan, Li, Li-Zhen, Yin, Zi-Wei & Schülke, Michael, 2019, A review of the Tachinus longicornis - group of the subgenus Tachinoderus Motschulsky (Coleoptera: Staphylinidae: Tachyporinae) from China, Zootaxa 4545 (4), pp. 478-494 : 479-481

Tachinus (Tachinoderus) bilobus Chang, Li & Yin , new species

Chinese Common Name: 双叶圆胸隐翅虫

( Figs 1–2 , 12 )

Type material (19 exs). Holotype: CHINA: Ƌ: ‘ China: Hubei Prov., Shennongjia (神农架), Muyu (木鱼), 6.viii.2002, Li & Tang leg.’ ( SNUC) . Paratypes: CHINA: 4 ƋƋ, 4 ♀♀: same label date as Holotype; 4 ♂♂, 1 ♀: ‘ China: Sichuan Prov., Chengdu, Qingcheng Mt. (青城山), 20.vii.2003, Li-Zhen Li leg.’; 1 ♂, 4 ♀♀: same label data, except ‘ 19.vii.2003, Hu & Tang leg.’ (all in SNUC) .

Diagnostic description. Male. Habitus as in Fig. 1A ; TBL 3.82–4.14 mm, FBL 2.36–2.68 mm; head, pronotal disc, elytra and abdomen black, antennomeres I–II, mouthparts, pronotal posterolateral areas and most parts of legs reddish-brown, tarsi yellowish-brown. Head sub-triangular, HL 0.33–0.42 mm, HW 0.75 mm, with microsculpture and finely punctures at posterior portion; eyes prominent, EyL 0.19–0.24 mm; antenna elongate, AnL 2.17–2.26 mm, relative lengths of antennomeres I–XI: 1.25: 1: 1.75: 1.5: 1.5: 1.5: 1.5: 1.25: 1.25: 1: 1.75. Pronotum strongly transverse, PL 0.80–0.85 mm, PW 1.37–1.46 mm, PI = 0.58–0.59. Elytra slightly transverse, EL 1.18– 1.27 mm, EW 1.37–1.41 mm, EI = 0.86–0.90. Abdominal surface with microsculpture consisting of transverse waves; tergite VIII ( Fig. 2A ) with four short lobes, inner lobes much longer than outer ones; sternite VII ( Fig. 2B ) shallowly and broadly emarginate at middle along posterior margin, granules evenly arranged in sub-triangular area; sternite VIII ( Fig. 2C ) with two lobes, deeply incised in between, median length of sternite 0.65 times as long as depth. Length of aedeagus ( Fig. 2 D–E) 0.83 mm, parameres short and wide, each slightly angulate at apex in ventral view, slightly curved ventrally in lateral view.

Female. General habitus ( Fig. 1B ) similar to male. Measurements: TBL 4.00– 4.23 mm, FBL 2.64–2.82 mm, HL 0.38–0.47 mm, HW 0.80 mm, EyL 0.19 mm, AnL 2.12–2.26 mm, PL 0.85–0.89 mm, PW 1.37–1.55 mm, PI 0.57–0.58, EL 1.27–1.32 mm, EW 1.46–1.51 mm, EI 0.87–0.88. Tergite VIII ( Fig. 2F ) with four lobes, inner lobes slightly longer than outer ones, incision between inner lobes V-shaped, sternite VIII ( Fig. 2G ) with six lobes, fimbriate lobes longer than others.

Comparative notes. Tachinus bilobus is similar to T. lobutulus (described below) and T. longicornis Motschulsky in sharing a stout aedeagus with relatively broad parameres. Tachinus longicornis is readily distinguishable from both former species by the parameres of the aedeagus being distinctly exceeding apex of the median lobe, while T. bilobus differs from T. lobutulus in the female tergite VIII with the inner lobes being longer than the outer ones (the inner lobes are much shorter than outer lobes in T. lobutulus ).

Distribution. China: Hubei, Sichuan ( Fig. 12 ).

Etymology. The new specific epithet refers to the bi-lobed male sternite VIII.

Figures

FIGURE 1. Habitus of Tachinus bilobus. A. Male. B. Female. Scale bar: 1.0 mm.

FIGURE 2. Diagnostic features of Tachinus bilobus (A–E. Male. F–G. Female). A, F. Tergite VIII. B. Sternite VII. C, G. Sternite VIII. D–E. Aedeagus, in ventral (D) and lateral (E) view. Scale bar: 0.2 mm.

FIGURE 12. Distribution of the Chinese species of the Tachinus longicornis-group. Star—T. bilobus; Pentagon—T. centralis; Square—T. curvipennis; Diamond—T. lobutulus; Triangle—T. ohbayashii (red triangle represents published data, pink ones are new records); Circle—T. tangliangi (note this species also extends its distribution to northern Thailand).