Trichotichnus (s. str.) subangulatus Ito, 2021

(Figs. 55, 74, 77–83 & 87)

Trichotichnus (Trichotichnus) subangulatus Ito, 2021b: 71 .

Material examined. China. YUNNAN: 1 male, 3 females, Gongshan, Cikai Town, 0.5 km of Kongdang, 27.88111°N 98.34063°E, 1500 m, 25.X.2004 night, D. Kavanaugh leg. (IOZ, CAS) ; 3 males, 2 females, Gongshan, Dulongjiang, 2.8 km S Longyuan Vill., 28.00905°N 98.32204°E, 1660 m, 31.X.2004 Night, D. Kavanaugh, D.Z. Dong leg. (IOZ, CAS) ; 1 female, Gongshan, Dulongjiang, Maku, Wood, vegetation, 27.68875°N 98.31303°E, 1677 m, 3.IX.2006, Liu Ye leg. (IOZ) ; 2 males, 1 female, Baoshan Pref., Gaoligong Shan, 65 km NNE Tengchong, 1750 m, 25°35'20"N 98°40'21"E, sec. mixed forest, overgrown stone debris, litter and moss sifted, 27.VIII.2009, D.W. Wrase leg. [10] (cWR); 1 f, Santaishan, 30 km SW Mangshi, 1200 m, 18.V.1955, U Lo leg. (ZIN) ; 1 male, 1 female, Jinping: Shilicun Forest Station, 1960 m, 22°46'28.4"N 103°17'49.3"E, 16.XII.2003, B. Kataev leg. [5] (ZIN) . GUANGXI: 1 male, 1 female, Longsheng, Huaping Nature Reserve, Hongtan, light trap, 4.X.2007, night, Liu Chunxiang leg. (IOZ) .

Vietnam. LAO CAI: 2 males, 40 km WNW of Lao Cai, env. Y Ty, Bat Hat Natn. Park, 1600–1900 m, 22°37′– 37.6′N 103°37.3′–28.3E, 16–21.X.2018, D. Fedorenko leg. (SIEE) ; 1 female, Sa Pa, at light, 23.IV.–6.V.2013, A. Prosvirov leg. (SIEE) . CAO BANG: 1 male, vic. Vin Den, Nui Pia Oac Nature Res., 22°33′53′′N 105°52′53′′E, 900–1300 m, 06–10.V.2013, A. Weigel leg. (NME) ; 1 female, 40 km W of Cao Bang Phia Oac Mt., h ~ 1650–1700 m, deciduous forest, 3–11.X.2018, D. Fedorenko leg. (SIEE) .

Re-description. Body length 7.7–9.6 mm. Habitus as in Fig. 74.

Morphological character states are as described for T. schmidti sp. n., but differing as follows.

Ventral side of body blackish brown, with medial portions in most specimens paler. Labrum markedly concave anteriorly. Left mandible in frontal view wide and truncate at tip (Fig. 55). Pronotal sides either rounded along entire length, more widely in basal half than in apical half, or very shallowly sinuate before basal angles; apical margin markedly emarginate; basal angle obtusangular, sharp at apex, in most specimens with a very small obtuse denticle at tip. Last visible abdominal sternite (VII) in male rounded or subtruncate at apex.

Median lobe of aedeagus (Figs. 77–81) in lateral view arcuate, with apical third rather strongly, somewhat angularly curved ventrally; ventral margin in basal two thirds almost straight; apex thin, not prominent dorsally or ventrally; in dorsal view median lobe comparatively wide, only slightly narrowed apically, with terminal lamella (Fig. 77) very wide and short, roundly narrowed posteriorly. Ventral side edged laterally in apical part and depressed between margins. Apical orifice in dorsal position, wide apically. Internal sac with narrow spiny patches along sides apically.

Female genitalia (Figs. 82 & 83): gonocoxite moderately wide in ventral view, about 0.6 times as long as gonosubcoxite, with wide base.

Proportions (6 males and 8 females measured): HWmax/PWmax 0.68–0.74; HWmin/PWmax 0.51–0.59; HWmax/HWmin 1.24–1.40; PWmax/PL 1.45–1.63; PWmax/PWmin 1.16–1.27; EL/EW 1.47–1.62; EL/PL 2.98–3.29; EW/PWmax 1.24–1.38.

Comparison. In addition to the distinctive features of the male genitalia, this species can be distinguished from T. doiinthanonensis, T. schmidti sp. n., T. fedorenkoi sp. n. and T. noctuabundus by having labrum more deeply concave anteriorly, left mandible in frontal view wider and truncate at apex, and pronotum in most specimens with small denticle at apex.

Distribution (Fig. 87). Described from North Vietnam (type locality: Sapa). Known from North Vietnam (Lao Cai and Cao Bang provinces) and China (northwestern and southern Yunnan and Guangxi); it is the first record for China. The species occurs at altitudes of about 1400–2000 m.

Remarks. The identity of the following four males is obscure and requires further study.

China. Yunnan: 1 male, Gongshan, Dulongjiang, Elidang Village, beach 28.00287°N, 98.32145°E, 1640 m, 2004.11.3 Night D. Kavanaugh, D.Z. Dong (IOZ) ; 1 male, Gongshan, Dulongjiang, 2.8 km S Longyuan Vill., 28.00905°N 98.32204°E, 1660 m, 31.X.2004, D. Kavanaugh, D.Z. Dong leg. (CAS) ; 1 male, Gongshan, Dulongjiang, 2.3 km S Longyuan, 28.00532°N 98.32145°E, 1685 m, 2.XI.2004, D. Kavanaugh leg. (ZIN) .

Vietnam. Lao Cai: 1 male, 6 km NW Sa Pa, 22°21′39′′N 103°47′19′′E, 1810 m, pasture margin, 7.VIII.2013, V. Assing [8+2] (MFNB) .

These males differ from other examined males in the median lobe of the aedeagus (Figs. 84–86) which in lateral view is less strongly curved, with the apical third more evenly bent ventrally. In other characters including the armature of the internal sac (in all examined specimens, the internal sac is partly everted), they are not distinguishable from other specimens of T. subangulatus (Fig. 75). All four males were collected together with typical specimens of this species (Fig. 88). The presence of several specimens with similar characteristics of the median lobe indicates that they can belong to a separate sympatric species, but additional material and more detail studies are needed to completely determine their taxonomic status.

Their proportions (all 4 males measured): HWmax/PWmax 0.71–0.73; HWmin/PWmax 0.54–0.55; HWmax/ HWmin 1.29–1.36; PWmax/PL 1.47–1.53; PWmax/PWmin 1.17–1.24; EL/EW 1.48–1.58; EL/PL 3.09–3.13; EW/ PWmax 1.31–1.39. Body length 8.1–8.9 mm.