Holotype : male (SYSU), China, Yunnan, Xishuangbanna Dai Autonomous Prefecture, Mengla County, Menglun Reservoir,21°55'57"N, 101°11'25"E, 710 m, 5.vii.2016, Jiang, Liu, Huang & Liu leg. Paratypes: 4 spec. (SYSU), same data as the holotype.

Length 5.4–5.7 mm. Head, pronotum and elytra with similar punctation. Prosternal carina with a prominent tooth anteromedially. Elytra slightly parallel-sided in the middle, without serial punctures laterally. Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with distinct median carina on basal two-thirds. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 1D, E): 1.1 mm long. Median lobe slightly emarginated apically, slightly widened in the middle; gonopore situated subapically. Parameres longer than median lobe, strongly expanded and truncate at apex, outer apical angle rounded and inner apical angle nearly rectangular; apex of parameres wider than apex of median lobe.

Figure 1. 

Coelostoma (Lachnocoelostoma) bannanicum Mai & Jia, sp. nov. A dorsal view B ventral view C lateral view D, E aedeagus (D dorsal view E ventral view). Scale bars :1.0 mm (A–C); 0.5 mm (D, E).

Form and colour (Fig. 1A–C). Total length 5.4–5.7 mm (holotype: 5.6 mm); maximum width 3.1–3.3 mm (holotype: 3.2 mm); body broadly oval, slightly parallel-sided in the middle, moderately convex. Dorsum black and shiny. Labrum, maxillary palpi and labial palpi reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface reddish brown to black. Femora and tibiae dark reddish brown, tarsi pale reddish.

Head. Dorsal surface with dense fine punctures. Interstices between punctures smooth. Clypeus subtruncate anteriorly. Eyes of moderate size, distinctly emarginated anteriorly in lateral view, separated by ca. 3.6 × the width of one eye. Mentum strongly emarginate anteriorly and depressed in anterior half, with sparse punctures except on the depressed portion. Antennae with 9 antennomeres, antennal club (antennomeres 7–9) densely pubescent. Maxillary palpomere 2 strongly swollen, palpomere 4 truncate apically, slightly longer than palpomere 3. Gula narrow and glabrous.

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad, with punctures as on head, anterolateral angles obtusely rounded, posterolateral angles blunt, anterior and lateral margins with narrow marginal bead. Prosternum with a carina medially and a prominent tooth anteromedially. Scutellum almost in shape of equilateral triangle, with punctures finer than those on pronotum. Elytra with more or less coarser punctures than those on pronotum, punctures on lateral and posterior portions somewhat coarser than those on disc; elytra without serial punctures; sutural stria reaching anterior third of elytra; lateral margin of elytra with bead but not explanate.

Legs. Pro- and mesofemora bearing dense pubescence, except on extreme apex. Metafemora not pubescent, with dense microsculptures and spares fine punctures. Meso- and Metatibiae slightly flattened, with strong apical spurs and series of sparse stout spines laterally. Tarsi with long dorsal setae and gold ventral setae; metatarsi with fifth tarsomere almost as long as third and fourth combined. Claws curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First ventrite with distinct median carina on basal two-thirds. Fifth ventrite with fine marginal bead and slightly emarginated apically, with a row of stout setae apically.

Male genitalia (Fig. 1D, E). Aedeagus ca. 1.1 mm long. Median lobe slightly emarginated apically, widest in the middle, ca. 3.2 × as long as wide. Gonopore situated subapically, wider than long. Parameres longer than median lobe; outer face strongly sinuate at anterior third, strongly expanded and truncate at apex, outer apical angle rounded and inner apical angle nearly rectangular; apex of parameres wider than apex of median lobe.

This species is named after the type locality, Xishuangbanna Dai Autonomous Prefecture.

On the basis of private communication to the collector, Dr. Ri-Xin Jiang (Guizhou University), the specimens were collected under stones at the edges of a mountain stream.

This species is very similar to C. coomani Orchymont, 1932 and C. jaechi Jia, Lin, Chan, Skale & Fikáček, 2017 in the weakly emarginate apex of the median lobe, and to C. surkhetensis Hebauer, 2002 in the shape of the median lobe. It can be distinguished from C. coomani (Jia et al. 2014: fig. 24) by the gonopore situated subapically (Fig. 1D, E) (situated at midlength in C. coomani) and outer margin of parameres strongly sinuate subapically (Fig. 1D, E) (not or only slightly sinuate in C. coomani). It differs from C. jaechi (Jia et al. 2017: fig. 11) by larger body size (body size < 5 mm in C. jaechi), median lobe widest at midlength (Fig. 1D, E) (widest in apical third in C. jaechi). It can be distinguished from C. surkhetensis (Fig. 8A–E) by parameres strongly expanded apically (Fig. 1D, E) (apex not expended in C. surkhetensis (Fig. 8D, E)), median lobe widest at midlength (Fig. 1D, E) (outer face subparallel throughout in C. surkhetensis (Fig. 8D, E)).

Only known from type locality. China (Yunnan).

Holotype : male (SYSU), China, Yunnan, Honghe Hani and Yi Autonomous Prefecture, Lvchun County, Huanglianshan Mountain, Huanglianshan Reservoir (黄连山水库), 22.8898°N, 102.2952°E, 1717.3 m, 30.iv.2021, in a forest stream at night, Jiang, Yang, Huang & Mai leg. Paratypes: 2 males (SYSU), same data as the holotype.

Figure 2. 

Coelostoma (Lachnocoelostoma) dactylopunctum Mai & Jia, sp. nov. A dorsal view B ventral view C lateral view D, E aedeagus (D dorsal view E ventral view). Scale bars: 1.0 mm (A–C); 0.5 mm (D, E).

Length 4.3–4.5 mm. Head and pronotum with similar punctation. Prosternum carinate medially, with a fine tooth anteromedially. Elytra not parallel-sided in the middle, each elytron with ten distinct rows of serial punctures; intervals between series with two sizes of punctures especially in posterior half of elytron, the finer punctures as on pronotum and much finer and shallower than the coarser punctures, coarser punctures almost as coarse as those of the series (Fig. 12A). Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with complete median carina. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 2D, E): 0.87 mm long. Median lobe emarginate apically, outer face nearly parallel-sided from basal to middle, then gradually narrowing towards apex, gonopore situated subapically, wider than long. Parameres slightly longer than median lobe, gradually expanded from anterior fourth to apex, broadly truncate apically, inner apical angle acute, pointed; middle part of parameres ca. 0.5 × as wide as median lobe at the same level.

Form and colour (Fig. 2D, E). Total length 4.3–4.5 mm (holotype: 4.5 mm); maximum width 2.8–3.0 mm (holotype: 3.0 mm); body broadly oval, not parallel-sided in the middle, moderately convex. Dorsum black to reddish brown, with lateral margin of pronotum and elytra paler. Labrum, maxillary palpi and labial palpi reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface reddish brown. Femora and tibiae dark reddish brown, tarsi pale reddish.

Head. Dorsal surface with dense fine punctures. Interstices between punctures smooth. Clypeus subtruncate anteriorly. Eyes of moderate size, slightly emarginated anteriorly in lateral view, separated by ca. 5.3 × the width of one eye. Mentum emarginate anteriorly and depressed in anterior half, with sparse punctures except on the depressed portion. Antennae with nine antennomeres, antennal club (antennomeres 7–9) densely pubescent. Maxillary palpomere 2 strongly swollen, palpomere 4 truncate apically, slightly longer than palpomere 3. Gula narrow and glabrous.

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad, with punctures as on head, anterolateral angles obtusely rounded, posterolateral angles blunt, anterior and lateral margins with narrow marginal bead. Prosternum with a carina medially and slightly projecting anteromedially. Scutellum in shape of equilateral triangle, with punctures as on pronotum. Each elytron with ten distinct rows of serial punctures; intervals between series with two sizes of punctures especially in posterior half of elytron, the finer punctures as on pronotum and much finer and shallower than the coarser punctures, coarser punctures almost as coarse as those of the series (Fig. 12A); series 1 and 2 reaching basal half of elytron, series 1 overlap with sutural stria; series 3 and 4 nearly reaching elytral base and fused together subposteriorly; series 5–10 reaching elytral base, slightly sulcate posteriorly; the outer four serial punctures coarser and stronger than the inner six serial punctures (Fig. 12A). Lateral margin of elytra with bead and slightly explanate.

Legs. Pro- and mesofemora bearing dense pubescence, except on extreme apex. Metafemora not pubescent, with dense microsculptures and spares fine punctures. Meso- and Metatibia slightly flattened, with strong apical spurs and series of sparse stout spines laterally. Tarsi with long dorsal setae and gold ventral setae; metatarsi with fifth tarsomere almost as long as third and fourth combined. Claws curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First ventrite with complete median carina. Fifth ventrite slightly emarginate and with fine marginal bead, with a row of stout setae apically.

Male genitalia (Fig. 2D, E). Aedeagus ca. 0.87 mm long. Median lobe emarginate apically, widest basally, ca. 3.5 × as long as wide; outer face nearly parallel-sided from base to middle, then gradually narrowing towards apex; gonopore situated subapically, wider than long. Parameres slightly longer than median lobe, gradually expanded from anterior fourth to apex, broadly truncate apically, inner apical angle acute, pointed; middle part of parameres ca. 0.5 × as wide as median lobe at the same level.

The species name is a combination of Dactylosternum, a genus in the same tribe Coelostomatini, and the Latin punctum. The name refers to the fact that this species with distinct serial punctures on elytra which is similar to many species of Dactylosternum Wollaston, 1854.

Aquatic. Adults were found on the edges of a forest stream at night.

This species is easily recognized as a member of Dactylosternum by the ten rows of serial punctures on elytra, which is different to any known Coelostoma species. Coelostoma martensi Hebauer, 2002 and C. gentilii Jia, Aston & Fikáček, 2014 (Fig. 13B) are also known with serial punctures on elytra, but only visible laterally. Coelostoma rubens Hebauer, 2002 (Jia et al. 2019: figs 4, 5), C. jaculum Jia, Angus & Bian, 2019 (Jia et al. 2019: figs 2, 3) and C. phototropicum Jia, Angus & Bian (Jia et al. 2019: fig. 1) are similar to this new species in the shape of aedeagus. However, none of these species with serial punctures on elytra.

Only known from type locality. China (Yunnan).

Holotype : male (SYSU), China, Yunnan, Dehong Dai and Jingpo Autonomous Prefecture, Yingjiang County, Xima Town (昔马镇), Hulukou (葫芦口), Xingyun Secondary power station (星云二级电站), 1000 m, vi.2019, light trap, Zhao-yang Tang leg. Paratypes: 2 females (SYSU), same data as the holotype.

Length 4.4–4.6 mm. Head and pronotum with similar punctation. Prosternum carinate medially, with a prominent tooth anteromedially. Elytra not parallel-sided in the middle, each elytron with 10 distinct rows of serial punctures; intervals between series with two sizes of punctures especially in posterior half of elytron, all finer than those of the series, the finer punctures finer and shallower than the coarser punctures but not extremely so (Fig. 12B); lateral margin of elytra with bead but not explanate. Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with carina on basal two-thirds. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 3D, E): 1.1 mm long. Median lobe widest basally, almost truncate apically, outer face nearly parallel-sided throughout; gonopore situated subapically, rounded, almost as wide as long. Parameres almost the same length as median lobe, outer face continually curved, apex of paramere pointed, curved inwards.

Form and colour (Fig. 3A–C). Total length 4.4–4.6 mm (holotype: 4.5 mm); maximum width 2.6–2.7 mm (holotype: 2.7 mm); body broadly oval, not parallel-sided in the middle, moderately convex. Dorsum black to reddish brown, with lateral margin of pronotum and elytra slightly paler. Labrum, maxillary palpi and labial palpi reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface reddish brown. Femora and tibiae dark reddish brown, tarsi pale reddish.

Head. Dorsal surface with dense fine punctures. Interstices between punctures smooth. Clypeus subtruncate anteriorly. Eyes of moderate size, slightly emarginated anteriorly in lateral view, separated by ca. 4.2 × the width of one eye. Mentum emarginated anteriorly and depressed in anterior half, with sparse punctures and transverse microsculpture. Antennae with 9 antennomeres, antennal club (antennomeres 7–9) densely pubescent. Maxillary palpomere 2 strongly swollen, palpomere 4 truncate apically, slightly longer than palpomere 3. Gula narrow and glabrous.

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad, with punctures slightly sparser than those on head, anterolateral angles obtusely rounded, posterolateral angles blunt, anterior and lateral margins with narrow marginal bead. Prosternum with a carina medially and a prominent tooth anteromedially. Scutellum in shape of equilateral triangle, with punctures as on pronotum. Each elytron with ten distinct rows of serial punctures; intervals between series with two sizes of punctures especially in posterior half of elytron, all finer than those of the series, the finer punctures finer and shallower than the coarser punctures but not extremely so (Fig. 12B); series 1–4 only visible in posterior half of elytron, series 1 overlaps with sutural stria, series 3 and 4 fused together subposteriorly; series 5–10 nearly reaching elytral base, slightly sulcate posteriorly. The outer four serial punctures coarser and stronger than the inner six serial punctures (Fig. 12B). Lateral margin of elytra with bead but not explanate.

Figure 3. 

Coelostoma (Lachnocoelostoma) fortunum Mai & Jia, sp. nov. A dorsal view B ventral view C lateral view D, E aedeagus (D dorsal view E ventral view). Scale bars: 1.0 mm (A–C); 0.5 mm (D, E).

Legs. Pro- and mesofemora bearing dense pubescence, except on extreme apex. Metafemora not pubescent, with dense microsculptures and spares fine punctures. Meso- and Metatibia slightly flattened, with strong apical spurs and series of sparse stout spines laterally. Tarsi with long dorsal setae and gold ventral setae; metatarsi with fifth tarsomere almost as long as third and fourth combined. Claws curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First ventrite with distinct median carina on basal two-thirds. Fifth ventrite slightly emarginate and with fine marginal bead, with a row of stout setae apically.

Male genitalia (Fig. 3D, E). Aedeagus ca. 1.1 mm long. Median lobe widest basally, ca. 3.9 × as long as wide, almost truncate apically, outer face nearly parallel-sided throughout; gonopore situated subapically, rounded, almost as wide as long. Parameres almost the same length as median lobe, outer face continually curved, apex of paramere pointed, curved inwards.

This new species is derived from the Latin adjective fortuna, fortunate, meaning the senior author was lucky to collect the new species.

All specimens were collected in a light trap

This species also with ten rows of serial punctures on elytra as C. dactylopunctum sp. nov. It can be distinguished from the latter by apex of median lobe truncate and not emarginate (Fig. 3D, E) (slightly emarginate and rounded apically in C. dactylopunctum sp. nov. (Fig. 2D, E)), apex of paramere pointed (Fig. 3D, E) (paramere broadly truncate apically in C. dactylopunctum sp. nov. (Fig. 2D, E)), first ventrite with median carina on basal two-thirds (with complete median carina in C. dactylopunctum sp. nov.).

Only known from type locality. China (Yunnan).

Holotype : male (SYSU), China, Fujian, Wuyishan, Sangang Village (三港村), 16–28.v.2004, Cai-xia Yuan & Jing Li leg.

Length 6.13 mm. Head, pronotum and elytra with similar punctation. Prosternum carinate medially, with a prominent tooth anteromedially. Elytra parallel-sided in the middle, without serial punctures laterally. Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with median carina on basal one-thirds. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 5A–C): very large, similar to Coelostoma vagum Orchymont, 1940, but median lobe narrowly rounded apically, apex without a sharp prominent tooth ventrally; parameres abruptly widened apically, distinctly bent inward.

Form and colour (Fig. 4A–C). Total length 6.13 mm; maximum width 3.3 mm; body broadly oval, parallel-sided in the middle, moderately convex. Dorsum black and shiny. Labrum, maxillary palpi and labial palpi reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface reddish brown to black. Femora and tibiae dark reddish brown, tarsi pale reddish.

Figure 4. 

Coelostoma (Lachnocoelostoma) mixtum Mai & Jia, sp. nov. A dorsal view B ventral view C lateral view. Scale bar: 1.0 mm (A–C).

Head. Dorsal surface with dense fine punctures. Interstices between punctures smooth. Clypeus subtruncate anteriorly. Eyes of moderate size, distinctly emarginate anteriorly in lateral view, separated by ca. 4 × the width of one eye. Mentum strongly emarginated anteriorly and depressed in anterior half, with sparse fine punctures. Antennae with nine antennomeres, antennal club (antennomeres 7–9) densely pubescent. Maxillary palpomere 2 strongly swollen, palpomere 4 truncate apically, slightly longer than palpomere 3. Gula narrow and glabrous.

Figure 5. 

Aedeagus of Coelostoma mixtum Mai & Jia, sp. nov. and Coelostoma vagum Orchymont, 1940. A–C C. mixtum sp. nov. A dorsal view B lateral view C ventral view D–F C. vagum D dorsal view E lateral view F illustration by Orchymont (1940). Scale bar: 0.5 mm (A–E).

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad, with punctures as on head, anterolateral angles obtusely rounded, posterolateral angles blunt, anterior and lateral margins with narrow marginal bead. Prosternum with a carina medially and a prominent tooth anteromedially. Scutellum in shape of equilateral triangle, with punctures finer and denser than those on pronotum. Elytra with punctures as on pronotum; elytra without serial punctures; sutural stria reaching anterior half of elytra; lateral margin of elytra with bead but not explanate.

Legs. Pro- and mesofemora bearing dense pubescence, except on extreme apex. Metafemora not pubescent, with dense microsculptures and spares fine punctures. Meso- and Metatibia slightly flattened, with strong apical spurs and series of sparse stout spines laterally. Tarsi with long dorsal setae and gold ventral setae; metatarsi with fifth tarsomere almost as long as third and fourth combined. Claws curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First ventrite with distinct median carina on basal one-thirds. Fifth ventrite with fine marginal bead and slightly emarginate apically.

Male genitalia (Fig. 5A–C). Aedeagus very large, 2.3 mm long. Median lobe widest at midlength, ca. 5 × as long as wide; median lobe gradually narrowing towards apex, with a small finger like apex, narrowly rounded apically; gonopore rounded, situated subapically; parameres much longer than the median lobe, abruptly widened apically, distinctly bent inward.

This species is derived from the Latin verb mixtus, mix, refers to the fact that this species is similar to Coelostoma vagum Orchymont, 1940 in shape of the median lobe and similar to C. wui Orchymont, 1940 in shape of parameres.

Unknown, this species was collected with C. wui Orchymont, 1940 in the same place.

The holotype of this species was identified as C. vagum Orchymont, 1940 in Jia et al. (2017). However, it is different from C. vagum in the form of the aedeagus. Hence, the distribution of C. vagum in Fujian needs to be verified. This species is the seventh known species of the Coelostoma phallicum group. This group can be recognized by a large and very elongate aedeagus with an extremely reduced phallobase and large subapical gonopore (Liu et al. 2020). This species is most similar to C. vagum Orchymont, 1940 (Fig. 5D–F) and C. bipunctatum Jayaswal, 1972 in shape of the median lobe but can be distinguished from them by the narrowly rounded apex of median lobe (apex pointed in C. vagum and C. bipunctatum), median lobe widest in the middle (median lobe nearly parallel-sided in the middle in C. vagum and C. bipunctatum). It also can be distinguished from C. vagum by apex of median lobe without a sharp prominent tooth ventrally (Fig. 5B) (apex with a sharp prominent hook-shaped tooth ventrally in C. vagum (Fig. 5E))

Only known from type locality. China (Fujian).

Holotype : male (SYSU), China, Guangdong, Longmen County, Nankunshan Mountain, Guanyintan (观音潭), 23°38'13"N, 113°51'1"E, 503.7 m, 24.iii.2021, Mai, Jiang, Yang & Huang leg. Paratypes: 14 spec. (SYSU), 2 spec. (IZCAS), same data as the holotype;

Length 4.7–5.0 mm. Head, pronotum and elytra with similar punctation. Prosternum carinate medially, with a prominent tooth anteromedially. Elytra slightly parallel-sided in the middle, without serial punctures laterally. Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with median carina on basal two-thirds. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 6D–F): similar to Coelostoma turnai Hebauer, 2006 (Jia et al. 2014: fig. 21), but median lobe wider and shorter, outer face of parameres distinctly incised subapically.

Figure 6. 

Coelostoma (Lachnocoelostoma) nankunshanense Mai & Jia, sp. nov. A dorsal view B ventral view C lateral view D–F aedeagus D, E holotype D dorsal view E ventral view F aedeagus of a paratype (dorsal view). Scale bars: 1.0 mm (A–C); 0.5 mm (D–F).

Form and colour (Fig. 6A–C). Total length 4.7–5.0 mm (holotype: 4.9 mm); maximum width 2.6–3.2 mm (holotype: 3.0 mm); body broadly oval, slightly parallel-sided in the middle, moderately convex. Dorsum black and shiny. Labrum, maxillary palpi and labial palpi reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface reddish brown to black. Femora and tibiae dark reddish brown, tarsi pale reddish.

Head. Dorsal surface with dense fine punctures. Interstices between punctures smooth. Clypeus subtruncate anteriorly. Eyes of moderate size, distinctly emarginate anteriorly in lateral view, separated by ca. 3.5 × the width of one eye. Mentum strongly emarginated anteriorly and depressed in anterior half, with sparse punctures and dense transverse microsculpture. Antennae with nine antennomeres, antennal club (antennomeres 7–9) densely pubescent. Maxillary palpomere 2 strongly swollen, palpomere 4 truncate apically, slightly longer than palpomere 3. Gula narrow and glabrous.

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad, with punctures as on head, anterolateral angles obtusely rounded, posterolateral angles blunt, anterior and lateral margins with narrow marginal bead. Prosternum with a carina medially and a prominent tooth anteromedially. Scutellum in shape of equilateral triangle, with punctures finer and denser than those on pronotum. Elytra with punctures as on pronotum, punctures on lateral and posterior portions somewhat coarser than those on disc; elytra without serial punctures; sutural stria reaching anterior third of elytra; lateral margin of elytra with bead but not explanate.

Legs. Pro- and mesofemora bearing dense pubescence, except on extreme apex. Metafemora not pubescent, with dense microsculptures and spares fine punctures. Meso- and Metatibia slightly flattened, with strong apical spurs and series of sparse stout spines laterally. Tarsi with long dorsal setae and gold ventral setae; metatarsi with fifth tarsomere almost as long as third and fourth combined. Claws curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First ventrite with distinct median carina on basal two-thirds. Fifth ventrite with fine marginal bead and slightly emarginate apically.

Male genitalia (Fig. 6D–F). Aedeagus ca. 1.0 mm long. Median lobe widest basally, bottle-shaped with apex emarginate (depth of emargination are variable in individuals as in Fig. 6F), ca. 1.8 × as long as wide; gonopore situated basally, wider than long; parameres slightly shorter than median lobe, distinctly incised on outer face subapically, broadly truncate apically

This species is named after the type locality, Nankunshan, a nature reserve in Guangdong Province.

(Figs 16G, K). All specimens were collected at night on some large stones in a forest stream. Individuals feed on algal mat and mate on the habitat. Some individuals of Coelostoma bifidum Jia, Aston & Fikáček, 2014 were also collected together.

Only known from type locality. China (Guangdong).

Holotype : male (SYSU), China, Yunnan, Honghe Hani and Yi Autonomous Prefecture, Lvchun County, Huanglianshan Mountain, Huanglianshan Reservoir (黄连山水库), 22.8898°N, 102.2952°E, 1717.3 m, 30.iv.2021, in a forest stream at night, Jiang, Yang, Huang & Mai leg.

Length 5.4 mm. Head and pronotum with similar punctation. Prosternum carinate medially, with a prominent tooth anteromedially. Elytra slightly parallel-sided in the middle, each elytron with ten serial punctures, somewhat difficult to separate them from the ground punctures in anterior half of elytron; intervals between series with two sizes of punctures especially in posterior half of elytron, coarser punctures slightly finer than those of the series (Fig. 13A). lateral margin of elytra with bead but not explanate. Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with carina on basal half. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 7D, E): 1.0 mm long. Median lobe widest at anterior third, rounded apically, outer face nearly parallel-sided in the middle; gonopore situated subapically, in shape of triangle, almost as wide as long. Parameres almost the same length as median lobe, straight, not curved, gradually narrowed from middle to apex, narrowly rounded apically.

Figure 7. 

Coelostoma (Lachnocoelostoma) pseudomartensi M Jia, sp. nov. A dorsal view B ventral view C lateral view D, E aedeagus D dorsal view E ventral view. Scale bars: 1.0 mm (A–C); 0.5 mm (D, E).

Form and color (Fig. 7A–C). Total length 5.4 mm; maximum width 3.3 mm; body broadly oval, nearly parallel-sided in the middle, moderately convex. Dorsum black, with lateral margin of pronotum and elytra dark reddish brown. Labrum, maxillary palpi and labial palpi reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface reddish brown. Femora and tibiae dark reddish brown, tarsi pale reddish.

Head. Dorsal surface with dense fine punctures. Interstices between punctures smooth. Clypeus subtruncate anteriorly. Eyes of moderate size, slightly emarginate anteriorly in lateral view, separated by ca. 4.5 × the width of one eye. Mentum strongly emarginate anteriorly and depressed in anterior half, with sparse punctures and transverse microsculpture. Antennae with 9 antennomeres, antennal club (antennomeres 7–9) densely pubescent. Maxillary palpomere 2 strongly swollen, palpomere 4 truncate apically, slightly longer than palpomere 3. Gula narrow and glabrous.

Thorax. Pronotum widest posteriorly, gradually narrowed anteriad, with punctures as on head, anterolateral angles obtusely rounded, posterolateral angles blunt, anterior and lateral margins with narrow marginal bead. Prosternum with a carina medially and a prominent tooth anteromedially. Scutellum slightly longer than wide, in shape of equilateral triangle, with punctures as on pronotum. Elytra with ground punctures as on pronotum, becoming coarser posteriorly. Each elytron with ten rows of serial punctures, somewhat difficult to separate them from the ground punctures in anterior half of elytron; intervals between series with two sizes of punctures especially in posterior half of elytron, coarser punctures slightly finer than those of the series; series 1 overlap with sutural stria; series 8 and 9 slightly sulcate posteriorly; series 10 short and becoming indistinct posteriorly (Fig. 13A). Lateral margin of elytra with bead, not explanate.

Legs. Pro- and mesofemora bearing dense pubescence, except on extreme apex. Metafemora not pubescent, with dense microsculptures and spares fine punctures. Meso- and Metatibia slightly flattened, with strong apical spurs and series of sparse stout spines laterally. Tarsi with long dorsal setae and gold ventral setae; metatarsi with fifth tarsomere almost as long as third and fourth combined. Claws curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First ventrite with distinct median carina on basal half. Fifth ventrite slightly emarginate and with fine marginal bead, with a row of stout setae apically.

Male genitalia (Fig. 7D, E). Aedeagus ca. 1.0 mm long. Median lobe widest at anterior third, ca. 3.7 × as long as wide, rounded apically, slightly narrowed in the middle; gonopore situated subapically, in shape of triangle, almost as wide as long. Parameres straight, widest basally, almost the same length as median lobe, not curved inwards, gradually narrowed from middle to apex, with a narrowed and rounded apex.

This species name is a combination of the Latin pseudo-, false, and another species of the genus, Coelostoma martensi. The name refers to the fact that this species is similar to C. martensi in some morphology characters.

This species lives mixed with Coelostoma dactylopunctum sp. nov.

This species is similar to Coelostoma martensi Hebauer, 2002 (Hebauer 2002: fig. 7; Jia et al. 2014: fig. 28) not only in the shape of aedeagus but also in the serial punctures on lateral elytra. It can be distinguished from the latter by median lobe widest subapically (widest medially in C. martensi), paramere with a narrowed and rounded apex (apex of paramere broad and truncate in C. martensi), elytron with ten rows of serial punctures (only with serial punctures sublaterally in C. martensi).

Only known from type locality. China (Yunnan).

China: Xizang: 1 male (SYSU), Muotuo County, Miri Village, 29°25'06"N, 95°24'23"E, 820 m, 23.vi.2018, Shi-shuai Wang & Zu-long Liang leg.; 6 spec. (SYSU), Muotuo County, Muotuo Town, 29.269°N, 95.227°E, 766 m, in a stream beside 219 national highway, Qian-le Lu leg.

Length 5.4–5.8 mm. Head, pronotum and elytra with similar punctation. Prosternum carinate medially, with a prominent tooth anteromedially. Elytra not parallel-sided in the middle, without serial punctures laterally. Mesofemora densely pubescent, except on extreme apex. First abdominal ventrite with distinct median carina on basal two-thirds. Fifth ventrite slightly emarginate and with a row of stout setae apically. Aedeagus (Fig. 8D, E): 1.2 mm long. Median subtruncate apically, nearly parallel-sided throughout; gonopore situated subapically.

Figure 8. 

Coelostoma (Lachnocoelostoma) surkhetensis Hebauer, 2002 A dorsal view B ventral view C lateral view D, E aedeagus D dorsal view E ventral view. Scale bars: 1.0 mm (A–C); 0.5 mm (D, E).

(Fig. 16H). On the basis of private communication to collector Mr. Qian-Le Lu, the specimens from Xizang were collected on wet stones on the edges of a forest stream. A single specimen of C. phototropicum Jia, Angus & Bian, 2019 was collected at the same place.

Previously known only from Nepal (Hebauer 2002; Przewoźny 2021). New record for China (Xizang).

China: Yunnan: 32 spec. (SYSU), Qvjing, Shizong (师宗) County, Fenghuanggu (凤凰谷) Valley, 24.618168°N, 104.264414°E, 929 m, 20.v.2021, Bao-ping Huang, Zhuo-yin Jiang & Zu-qi Mai leg.

In Yunnan, specimens were collected along sides of a rocky stream in a valley at night. Coelostoma coomani Orchymont, 1932 and C. phallicum Orchymont, 1940 were also collected in the same habitat. Adult individuals attracted by light (Jia et al. 2014). Parameres slightly longer than median lobe, gradually broadened from base to middle, outer face not curved, apical third parallel-sided, apex narrower than apex of median lobe, truncate, rounded outwards and nearly rectangularly inwards.

Figure 9. 

Dorsal view of Chinese Holocoelostoma A Coelostoma sulcatum Pu, 1963 B Coelostoma stultum (Walker, 1858). Scale bar: 1.0 mm (A, B).

China (Guangxi, Jiangxi, Yunnan), Thailand (Jia et al. 2014, 2017). New record for Yunnan.

China: Hunan: 30 spec. (SYSU), Yizhang, Mangshan Town, Xiling Village, 24°58'54"N, 112°49'15"E, 642 m, 8.vii.2021, Zu-long Liang leg.

China (Guangdong, Guangxi, Hunan). New record for Hunan.

China: Guangdong: 1 male (SYSU), Shenzhen City, Dapeng District, Tiantoushan Mountain, Light trap, 22°40'12"N, 114°24'45"E, 208 m, Yang, Jiang, Guo & Ji leg.

China (Hong Kong, Guangdong). New record for Guangdong.

China: Chongqing: 4 spec. (SYSU), Jiangjin District, Simianshan Nature Reserve, Dawopu (大窝铺), 20.vi.2014, Jian-yue Qiu & Hao Xu leg.; 1 spec. (SYSU), Jiangjin District, Simianshan Nature Reserve, Er’tai (二台), Hao Xu leg.; Fujian: 17 spec. (SYSU), Longyan (龙岩), Mt. Jiangshan(江山), 600 m, 7.iv.2020, Yu-chen Zheng leg.; Guizhou: 2 spec. (SYSU), Weng’ang Town, Maolan Nature Reserve, 25°15'08"N, 107°53'56"E, 814 m, 24.vii.2015, Ren-chao Lin & Yu-dan Tang leg.

(Fig. 16A). On basis of private communication with the collector Mr. Yu-Chen Zheng (China Agricultural University), the specimens from Fujian were collected on wet rocky ground beside a river at night.

Only known from China (Fujian, Guizhou, Hubei, Hunan, Chongqing) (Jia et al. 2014). New record for Fujian, Guizhou, and Chongqing.

China: Hunan: 4 spec. (SYSU), Taoyuan County, Wuyunjie, Zhushan Village, 100 m, 15.vi.2019, Hao Xu leg.; Henan: 2 spec. (SYSU), Neixiang County, Getiaopa Village (葛条爬村), 630 m, 22.vi.2021, Hao-yi Liu leg.; Shaanxi: 1 spec. (SYSU), Xi’an County, Dayu, 12.v.2011, Feng-long Jia leg.; Shandong: 3 spec. (HBUM): Feixian, Tashan Forest Farm, 16.–17.v.2007, Feng-yan Wang, Ji-liang Wang & Qi-qi Wu leg.; 2 spec. (HBUM): Pingyi, Dawa Forest Farm, 13–15.v.2007, Feng-yan Wang, Ji-liang Wang & Qiqi Wu leg.; Shanxi (山西) : 8 spec. (SYSU), Jincheng, Yangcheng (阳城) County, Manghe (蟒河) National Nature Reserve, 700 m, 27.iv.2016, Zu-qi Mai leg.; Zhejiang: 3 spec. (SYSU), Quanzhou City, Jiangshan County, Shuangxikou Town, Laofoyan Village (老佛岩村), 27°55'02.72"N, 119°11'34.47"E, 496 m, high-voltage mercury light trap, 11.viii.2018, Chen & Miao leg.; 7 spec. (SYSU), Lin’an City, Yinlongwu Town, Shibalongtan, 30°08'24.88"N, 118°52'23.56"E, 683 m, 28.iv.2018, Shifting, Cheng & Shen leg.; 2 spec. (SYSU), Jinhua City, Pan’an County, Lingjiangyuan (灵江源), 28°57'39.33"N, 120°38'59.72"E, 750 m, mixed leaf litter, Shifted, 21.V.2018, Puthz, Tang, Cheng & Shuai leg.

(possibly another undescribed species). China: Guangdong: 5 spec. (SYSU), Shaoguan City, Chebalin (车八岭) Nature Reserve, 23°14'46"N, 113°33'56"E, 496 m, 28–29.v.2017, Feng-Long Jia, Shi-Shuai Wang & Zu-Long Liang leg.; 24 spec. (SYSU), Shaoguan City, Chebalin (车八岭) Nature Reserve, 24°43'24"N, 114°15'23"E, 400 m, 24.viii.2020, Zu-Long Liang leg.; Jiangxi: 91 spec. (SYSU), Longnan, Jiulianshan, 06–vii.2008, Fenglong Jia leg.; Fujian: 2 spec. (SYSU), Wuyishan, Sangang, 16–28.v.2004, Cai-Xia Yuan & Jing Li leg.;

(Figs 15D, 16I, L). Collected on the ground beside a mountain river in Shanxi, active at night.

The specimens we studied contained two different forms of male genitalia (Fig. 14B–I). It may be inferred that the specimens treated by previous authors as C. wui Orchymont, 1940 possibly contain two species (see Discussion).

China (Hubei, Hunan, Jiangxi, Shaanxi, Shandong, Shanxi, Taiwan, Xinjiang, Zhejiang), Korea. (Hansen 1999; Jia et al. 2014; Liu et al. 2020). First record for Shanxi and Zhejiang.

Coelostoma sulcatum: Holotype (Fig. 10A, B): male (IZCAS), “Yunnan, Xishuangbanna, Gannanba / 540 m / 1952.IV.17 / Guang-Ji Hong leg. (with Chinese and Russian labels) // Coelostoma sulcata Pu // HOLOTYPE”; Paratype: male (SYSU), “Jingdong / 1200 m / 26.iv.1957 // A. Monchadskiy leg. (with Chinese and Russian labels) // Coelostoma sulcata Pu // Paratype”

Figure 10. 

Aedeagus of Coelostoma sulcatum Pu, 1963 (dorsal view) A, B holotype of C. sulcatum A labels B aedeagus C from Jing’an County (Jiangxi) D from Shenzhen City (Guangdong) E from Longlin County (Guangxi) F from Xishuangbanna (Yunnan) G from Xima (昔马) Town (Yunnan) H from Tongbiguan Town (Yunnan) I from Muotuo County (Xizang) J from Macao. Scale bar: 0.5 mm (A–J).

China: Fujian: 1 spec. (SYSU), Nanjing County, Hexi Town, in a pond, 13.vii.2010, Feng-long Jia leg.; 2 spec. (SYSU), Ningde District, Mountain behind Ningde Teachers College, 29°01'N, 115°16'E, 315 m, 2.x.2012, Ze-yu Wang leg.; 1 spec. (SYSU), Fu’an District, x.1963, Shan-xiang Lin leg.; Guangdong: 1 male (SYSU), Ruyuan County, Longxi, 4–5.x.1964, light trap; 1 spec. (SYSU), Zhuhai, Qi’ao Island, 12.vii.2005, Feng-long Jia leg.; 2 spec. (SYSU), Guangzhou, Shipai, pig farm, 25.vii.1985. Wu Wu leg.; 1 spec. (SYSU), Guangzhou City, Shipai, pig farm, 20.vii.1985. Wu Wu leg.; 1 spec. (SYSU), Guangzhou City, South bank of Zhujiang River, cattle farm, 10.x.1985. Wu Wu leg.; 1 spec. (SYSU), Guangzhou, viii.1938. Zhe-long Pu leg.; 3 spec. (SYSU), Shenzhen City, Inner Lingding Island, 8–12.iv.1998, Peng & Chen leg.; 33 spec. (SYSU), Shenzhen City, Dapeng Peninsula, Getian Village, 22.48157°N 114.52643°E, 12 m, 3.vii.2019, Feng-long Jia & Zu-qi Mai leg.; 1 male (SYSU), Shenzhen City, Dapeng Peninsula, Getian Village, 22°29'25"N, 114°30'59"E, -6 m, 14.xi.2020, Zu-qi Mai, Zhuoyin Jiang & Shu-jiao Jiang leg.; 1 spec (SYSU), Shenzhen City, Dapeng Peninsula, Jin’gui Village, 22°39'35"N, 114°23'10"E, 62 m, 15.v.2019, Wei-cai Xie leg.; 2 spec. (SYSU), Shenzhen City, Dapeng Peninsula, Paiyashan Mountain, 22°37'37"N, 114°26'17"E, 34 m, 5. xi.2018, Lan-bin Xiang leg.; 1 spec (SYSU), Shenzhen, 8–11.viii.2006, Feng-long Jia leg.; 3 spec. (SYSU), Shenzhen City, Pingtouling Mountain, 25.ix.2021, Bao-ping Huang leg.; 1 spec. (SYSU), Danxiashan Mountain, Jinshiyan, pool under a stone wall, 11.vi.2011, Feng-long Jia leg.; 1 male (SYSU), Fengkai County, Heishiding, in a pool, 13.viii.2010, Feng-long Jia leg.; 1 spec. (SYSU), Dinghushan Mountain, 4.vi.1958, Cui-ying Li leg.; Guangxi: 1 male (SYSU), Jinxiu County, Luoxiang, 400 m, 16.v.1999, Ming-yuan Gao leg.; 1 male (SYSU), Shangsi County, Hongqi Forestry Centre, 300 m, 29.v.1999, Xing Ke leg.; 4 spec. (SYSU), Nanning City, 22.vi.1958, Zhe-long Pu leg.; 6 spec (SYSU), Nanning City, 19.vi.1977, Zhi-he Huang leg.; Longlin County, Jinzhongshan Mountain, viii.2014, Shan-yi Zhou leg.; Jiangxi: 10 spec. (SYSU), Jing’an County, Zaodu (璪都) Town, Nanshan Village (南山村), 315 m, 29°01'N, 115°16'E, 2.viii.2015 Ren-chao Lin & Yu-dan Tang leg.; 4 spec. (SYSU), Jing’an County, Shanzhaolun, Tangli Village (塘里村), 260 m, 29°04'03"N, 115°17'23"E, 3.viii.2015, Ren-chao Lin & Yu-dan Tang leg.; 1 spec. (SYSU), Jing’an County, Jinggangshan, Bijiashan Mountain, 390 m, 26°31'12"N, 114°11'45"E, 22–25.vii.2014, light trap, Chen, Hu, Lv & Yu leg.; 1 spec. (SYSU), Jing’an County, Jinggangshan, Baiyinhu Lake, 800 m, 27.v.2011, Feng-long Jia leg.; Macao: 6 spec. (SYSU), Dangzai Mangrove Reserves, First area, 22°8'24"N, 113°33'11"E, 12 m, 16–17.i.2021, on edges of lagoon at night, Feng-long Jia & Zu-qi Mai leg.; 4 spec. (SYSU), Dangzai Mangrove Reserves, First area, 11–12.vii.2018, Feng-long Jia & Wei-cai Xie leg.; 4 spec. (SYSU), Dangzai Mangrove Reserves, First area, 10.x.2020, Feng-long Jia & Wei-cai Xie leg.; 1 spec. (SYSU), Dangzai Mangrove Reserves, First area, 17.vi.2016, Feng-long Jia leg.; 33 spec. (SYSU), Dangzai Mangrove Reserves, First area, 8.iv.2014, Wei-cai Xie & Jin-wei Li leg.; 1 spec. (SYSU), Dangzai Mangrove Reserves, First area, 3.xi.2014, Ren-chao Lin leg.; 1 spec. (SYSU), Coloane, KoloaneAlto (叠石塘), 27.iii.2014, Feng-long Jia leg.; Taiwan: 4 spec. (SYSU), Taidung County, Donghe Town, Xinchang (興昌), 25.x.2016, Wen-yi Zhou leg.; Xizang: 2 spec., Motuo, Beibeng, 850 m, 25.v.1983, Yinheng Han leg., each with a yellow label “Paratype, Coelostoma xizangensis, det. Wu Wu”; 1 male, same data as the former, but with a red label “Holotype, Coelostoma xizangensis, det. Wu Wu”; 1 female, same data as the former, but with a label “Allotype, Coelostoma xizangensis, det. Wu Wu”; 2 spec., same data as the former, but with a label “Coelostoma xizangensis”; 5 spec. (SYSU), Muotuo County, Miri Village, 29°25'06"N, 95°24'23"E, 800 m, 23.vi.2018, Shi-shuai Wang & Zu-long Liang leg.; Yunnan: 5 spec. (SYSU), Xishuangbanna Dai Autonomous Prefecture, Botanical Garden, Lake besides Royal Water Lily Hotel, 4–11.iv.2021, Bao-ping Huang leg.; 6 spec. (SYSU), Xishuangbanna Dai Autonomous Prefecture, Botanical Garden, Lake besides Royal Water Lily Hotel, 4–11.iv.2021, Bao-ping Huang leg.; 5 spec. (SYSU), Xishuangbanna Dai Autonomous Prefecture, Botanical Garden, Lake besides Royal Water Lily Hotel, 21.9295°N, 101.2483°E, 500 m, 2.v.2021, Zhuo-yin Jiang, Zhen-ming Yang, Bao-ping Huang & Zu-qi Mai leg.; 1 spec. (SYSU), Xishuangbanna Dai Autonomous Prefecture, Botanical Garden, 21.92262°N, 101.27710°E, 567 m, light trap, 23.v.2011, Ke-qing Song leg.; 2 spec. (SYSU), Xishuangbanna Dai Autonomous Prefecture, Naban Village, 7.i.2004, Li & Tang leg.; 2 spec. (SYSU), Mengla County, Wangtianshu Reserve, light trap, 22.vii.2014, Yun Li leg.; 1 spec. (SYSU), Xishuangbanna Dai Autonomous Prefecture, Gannanba, 500 m, 13.iii.1957, Qiu-zhen Liang leg.; 9 spec. (SYSU), Yingjiang County, Nabang Town, 24.75°N, 97.56°E, 239 m, 27.v.2016, Yu-dan Tang & Rui-juan Zhang leg.; 1 spec. (SYSU), Yingjiang County, Tongbiguan Town, Kaibangya Lake, 24.58°N, 97.67°E, 1289 m, 25.v.2016, Yu-dan Tang & Rui-juan Zhang leg.; 1 spec. (SYSU), Dehong Dai and Jingpo Autonomous Prefecture, Yingjiang County, Xima Town (昔马镇), Hulukou(葫芦口), Xingyun Secondary power station (星云二级电站), 1000 m, vi.2019, light trap, Zhao-yang Tang leg. Zhejiang: 1 male (SYSU), Lin’an County, Mt. Tianmushan, 300–400 m, 11–15.vi.2006, Hu & Wang Leg.; 1 spec (SYSU), Mt. W. Tianmushan, 10–21.viii.2004, N.-C. Li Leg.;

Length 4.5–5.8 mm. Head, pronotum and elytra with similar punctation. Prosternum moderately convex medially, not carinate, without anteromedian process. Elytra slightly or not parallel-sided in the middle, without serial punctures. Mesofemora without dense pubescence, but with punctures bearing strong setae laterally. First abdominal ventrite not carinate, fifth ventrite emarginate and with a row of stout setae apically. Aedeagus (Fig. 10B–J): 0.9–1.4 mm long. Median lobe widest basally, almost parallel from base to apical fourth, then distinctly narrowed apically (materials from Macao slightly narrowed); gonopore situated apically. Parameres longer than median lobe, outer face slightly curved or sinuate medially and strongly curved inwards apically.

(Figs 15G, H, 16B, F, J). This species can be found in various of aquatic environments. It can be collected on wet ground near rivers, streams or natural lakes. It also occurs at some artificial environments, such as on sandy gutters with very shallow flowing waters in Shenzhen (Fig. 16B), on the edges of an artificial lake (Fig. 15G) and also lives with Coelostoma phallicum Orchymont, 1940 in Xishuangbanna. It also occurs on the muddy edges of a brackish lagoon in a mangrove reserve in Macao (Fig. 15H). Adults are active at night and sometimes attracted by light.

Jia et al. (2014) thought this species was a synonym of Coelostoma stultum Walker. Liu et al. (2020) and Sheth et al. (2020) stated that it is a different species from C. stultum Walker after they studied a paratype of C. stultum, and considered as a likely synonym of Coelostoma bhutanicum Jayaswal, 1972 (Sheth et al. 2020). Here, we recovered the status of C. sulcatum Pu as a valid species.

Coelostoma sulcatum Pu, 1963 is morphologically variable in shape of aedeagus, especially in parameres. Compared with the original description (Jayaswal 1972) and photos of C. bhutanicum from india (Sheth et al. 2020), C. bhutanicum is very similar to C. sulcatum especially in aedeagus, which outer face of median lobe is slightly narrowing or subparalleling from base to apical fourth and distinctly narrowed subapically (Fig. 10B–I). This indicates C. bhutanicum and C. sulcatum possibly refer to the same species.

Liu et al. (2020) reported C. bhutanicum Jayaswal, 1972 from Taiwan. In his illustration of aedeagus, median lobe is of almost same width throughout, only slightly narrowed apically (Liu et al. 2020: fig. 2E). This character is inconsistent with the median lobe of C. bhutanicum drawn by Jayaswal (1972), but very closed to C. bhutanicum from Japan (Watanabe and Minoshima 2020) and C. sulcatum from Macao (Fig. 10J). This character has not been found in other specimens of C. sulcatum and C. bhutanicum. Hence, it is possible that the specimens with this character represent another undescribed species or just intraspecific variation of C. sulcatum. However, solving the problem of synonymization of C. bhutanicum and C. sulcatum is not easy until the type of C. bhutanicum can be examined. Hence, we prefer to treat specimens from China as C. sulcatum and not treat C. bhutanicum in the key to species of Chinese Coelostoma at present.

China (Fujian, Guangdong, Guangxi, Jiangxi, Macao, Taiwan, Yunnan, Xizang, Zhejiang).

For complete synonymy, see Hansen (1999).

China: Guangdong: 3 spec. (SYSU), Sihui District, Dasha Town, 5.vi.1998, Feng-long Jia leg.; 1 male (SYSU), Huaxian County, Dapuling, 26.viii.1983, Zhi-he Huang leg.; 2 spec. (SYSU), Lianjiang District, 25.ix.1985, Wu Wu leg.; 1 male (SYSU), Xinhui District, viii.2001, Xiao-li Tong leg.; Guangxi: 45 spec. (SYSU), Yangshuo (阳朔), viii.1984, Shou-jian Chen leg.; 6 spec. (SYSU), Shiwandashan Forest Park, 267 m, light trap, 9.vii.2011, Ke-qing Song leg.; Hainan: 1 male (SYSU), Lingshui, Diaoluoshan Mountain, Xiaomei (小妹), 29.xi.1963, Bai-ge Chen leg.; Hubei: 1 male (SYSU), Wuhan City, Wuhan Botanical Garden, 31.viii.2020, Zi-hao Shen leg.; Hunan: 2 spec. (SYSU), Yizhang (宜章), 16.iii.1941, Zhe-long Pu leg.; Jiangxi: 4 spec. (SYSU), Jing’an County, Guanyinyan (观音岩), 29°01'48"N, 115°25'00"E, 195 m, 1.viii.2015, Ren-chao Lin & Yu-dan Tang leg.; 3 spec. (SYSU), Jiujiang District, Duchang County, Linshan Village Committee, 15–20.viii.2010, Yan Mei leg.;Yunnan: 5 spec. (SYSU), Mengla Nature Reserve, 4–5.viii.2007, Jia-hui Li leg.; Zhejiang: 1 male (SYSU), Quzhou City, Kecheng District, 29.0063°N, 118.8063°E, 112 m, 15.iii.2020, Zhuo-yin Jiang leg.; 1 male (SYSU), Quzhou City, Kecheng District, Wangdu Village, 28.9875°N, 118.6898°E, 102 m, 7.iii.2020, Zhuo-yin Jiang leg.; 7 spec. (SYSU), Kaihua County, Zawanhua (砸碗花) Wetland Park, 11.iii.2020, Zhuo-yin Jiang leg.

Figure 11. 

Aedeagus of Coelostoma stultum (Walker, 1858) (dorsal view) A from Huaxian County (Guangdong) B from Sihui District (Guangdong) C from Mt. Shiwandashan (Guangxi) D from Yangshuo (Guangxi) E from Yizhang (Hunan) F from Mt. Diaoluoshan (Hainan). Scale bar: 0.5 mm (A–F).

Cambodia: 17 spec. (SYSU), Boeng, Kampong Thom Pro., Khleng, light trap beside a rice field, 13.viii.2017, Zu-qi Mai leg.

Length 4.3–5.2 mm. similar to C. sulcatum in morphological characters. Aedeagus (Fig. 11A–F): 0.8–1.0 mm long. Median lobe widest basally, distinctly narrowed medially, then slightly widened at apical third; gonopore situated apically. Parameres longer than median lobe, outer face continually curved and strongly curved inwards apically.

Figure 12. 

Lateral view of Coelostoma spp. (the red figures indicate the serial number of elytral serial punctures; the white arrows indicate the punctures of series; the circles indicate the coarser punctures; the squares indicate the finer punctures) A Coelostoma dactylopunctum sp. nov. B Coelostoma fortunum sp. nov. Scale bar: 1 mm (A, B).

This species has the similar habitations of C. sulcatum Pu, 1963.

Figure 13. 

Lateral view of Coelostoma spp. (the red figures indicate the serial number of elytral serial punctures; the white arrows indicate the punctures of series; the square indicates the elytral ground punctures) A Coelostoma pseudomartensi sp. nov. B Coelostoma gentilii Jia, Aston & Fikáček, 2014. Scale bar: 1 mm (A, B).

This species was reported widely distributed in China (Chongqing, Fujian, Guangxi, Guangdong, Jiangxi, Hainan, Hunan, Hong Kong, Shandong, Sichuan, Taiwan, Yunnan, Xizang) (Jia et al. 2014, 2017; Liu et al. 2020; Przewoźny 2021). However, some records should be based on misidentification. We examined all the specimens assigned as C. stultum in SYSU. After excluded the specimens of C. sulcatum, the distribution of C. stultum in China is confirmed: Guangdong, Guangxi, Jiangxi, Hainan, Hubei, Hunan, Taiwan, Yunnan, Zhejiang.

Figure 14. 

Aedeagus of Coelostoma wui Orchymont, 1940 (dorsal view) A illustration by Orchymont (1940) B from Pingyi County (Shandong) C from Getiaopa (葛条爬) Village (Henan) D from Hanzhong (Shaanxi) E from Taoyuan County (Hunan) F from Quanzhou City (Zhejiang) G from Wuyishan (Fujian) H from Mt. Jiulianshan (Jiangxi) I from Mt. Chebaling (Guangdong). Scale bar: 0.5 mm.

Figure 15. 

Habitats of Chinese Coelostoma A stone walls with running waters in forest (Yunnan) B wet stone walls with moss (Guangdong) C mountain stream in forest (Guangdong) D mountain river with rocky edges (Shanxi) E wastewater in city downtown (Guangdong) F lowland marshes with vegetation (Guangdong) G artificial lake (Yunnan) H brackish lagoon in mangrove reserve (Macao).

Figure 16. 

Habitats of Chinese Coelostoma spp. A C. turnai Hebauer, 2006 active at wet rocky ground beside a river at night (Fujian) B C. sulcatum Pu, 1963 on sandy gutterway with shallow flowing waters at night (Guangdong) C C. phallicum Orchymont, 1940 hided under a brick beside the wastewater during the day (Guangdong) D C. phallicum Orchymont, 1940 dived under water and fed on algal mats at night (Guangdong) E C. bifidum Jia, Aston & Fikáček on wet stone wall at night (Guangdong) F C. sulcatum Pu, 1963 on muddy edge of artificial lake at night (Yunnan) G C. nankunshanense sp. nov. on a stone in the middle of a forest stream at night (Guangdong) H C. surkhetensis Hebauer, 2002 in a wet stone on the edges of a forest stream at night (Xizang) I C. wui Orchymont, 1940 on the edges of a mountain river at night (Shanxi) J C. sulcatum Pu, 1963 on muddy edges of brackish lagoon at night, with a marine Amphipoda beside it (Macao) K C. nankunshanense sp. nov. mating at night (Guangdong) L C. wui Orchymont, 1940 ovipositing eggs on wet land at night (Shanxi).