New species and additional records of Lathrobium and Elytrobium from the Palaearctic region, with special reference to the fauna of East Yunnan (Coleoptera: Staphylinidae: Paederinae)

Seventeen species of Lathrobium Gravenhorst, 1802 and one of Elytrobium Assing, 2013 are (re-)described and illustrated: Lathrobium struyvei spec. nov. (Spain), a close relative of L. dimidiatipenne Bernhauer, 1910; L. kiruense spec. nov. (Nepal: Annapurna) of the L. emodense group; L. undosum spec. nov. (Nepal: Solu Khumbu), tentatively assigned to the L. discissum group; L. crenatum spec. nov. (China: East Yunnan), L. rostratum spec. nov. (China: East Yunnan), L. tricarinatum spec. nov. (China: East Yunnan), and L. laciniatum spec. nov. (China: East Yunnan), all four of them of the L. tentaculatum group; L. daweianum spec. nov. (China: Southeast Yunnan) of the newly established L. daweianum group; L. coadultum spec. nov. (China: Southeast Yunnan) of the newly established L. coadultum group; L. grebennikovi spec. nov. (China: Shaanxi: Qinling Shan) and L. cavisulcatum spec. nov. (China: Shaanxi: Qinling Shan) of the L. varisternale group; L. abruptum spec. nov. (China: Sichuan: Gongga Shan), a close relative of L. hailuogouense Peng et al., 2012; L. erectum spec. nov. (China: Guizhou: Fanjing Shan) of the L. fissispinosum group; L. scaphiforme spec. nov. (Japan: Honshu); L. volutum spec. nov. (Japan: Honshu); L. trabale spec. nov. (Japan: Honshu); L. oharai Watanabe, 2014; Elytrobium edentulum spec. nov. (China: Shaanxi: Qinling Shan). The diversity, biogeography, natural history, and phylogenetic affiliations of the Lathrobium fauna of East Yunnan, from where the genus is reported for the first time, are discussed. The general distribution of Lathrobium and the individual distributions of the newly described species in Yunnan are mapped. Additional records of 30 described and one unnamed Lathrobium species are reported from Middle Asia (one species), Nepal (five species), from the Chinese provinces Yunnan (five species), Sichuan (five species), Shaanxi (one species), and Guizhou (one species), from Taiwan (one species), and from Japan (13 species). Three of these species are reported from Japan for the first time. Additional records of two Elytrobium species are reported from China and Japan. Lathrobium is now represented in the Palaearctic region by 563 species and ten subspecies, in China by 206 species (67 of which are confined to Yunnan), in Japan by 114, and in the Himalaya by 70 species. Elytrobium currently includes a total of seven species distributed in China, Taiwan, and Japan.


Introduction
According to a previous contribution (Assing 2014a), the Holarctic genus Lathrobium Gravenhorst, 1802 was repre sented in the Palaearctic region sensu Smetana (2004) by 536 named species and ten subspecies, two nomina dubia not considered.In the meantime, the descriptions of eleven additional species from Italy, China, and Japan have been published (Bordoni & Magrini 2014;Peng et al. 2015;Watanabe 2014).The country with, by far, the greatest diversity is China (mainland), from where as many as 196 described species have been recorded, the vast majority of them micropterous and locally endemic.The fauna of Japan previously comprised 108 named species, 104 of them micropterous, three macropterous, and one wing-dimorphic (Assing 2013f;Watanabe 2014).According to a recent article specifically dealing with the Lathrobium fauna of Yunnan, 58 species were known from this province alone, making it by far the most diverse of all Chinese province faunas (Assing 2013c).Since then, four additional species have been described and one species has been moved to the new genus Sinlathrobium Assing, 2013 (Assing 2013d(Assing , 2013e, 2014a;;Peng et al. 2014), so that Lathrobium was previously represented in Yunnan by 61 exclusively micropterous and locally endemic species.Remarkably, all these species had been recorded from western Yunnan and not a single species was known from the east of the province.The genus Elytrobium Assing, 2013 previously included six species distributed in Japan (one species), Taiwan (one species), and China (four species).Material of Elytro bium species is extremely rare: three of the six species are represented only by their respective holotypes and, with one exception, all known records are based on single specimens (Assing 2013e).The present study is based on material collected during a recent field trip conducted by Michael Schülke and the author to eastern Yunnan in late summer 2014.This material included six undescribed micropterous Lathrobium species, the first records of the genus from this region.A study of Lathrobium from other regions made available to me by Aleš Smetana (Ottawa) and several other colleagues yielded eleven additional new species of Lathro bium and Elytrobium from Spain, Nepal, China, and Japan, as well as numerous records of zoogeographic interest, among them three newly recorded species from Japan.

Material and methods
The material treated in this study is deposited in the following public and private collections:

BMNH
The The morphological studies were conducted using a Stemi SV 11 microscope (Zeiss Germany) and a Jenalab compound microscope (Carl Zeiss Jena).The images of some forebodies, the aedeagi in dry preparation, and of the female tergites IX and X were created using a photographing device constructed by Arved Lompe (Nienburg) and CombineZ software.A digital camera (Nikon Coolpix 995) was used for the remaining photographs.The maps were created using MapCreator 2.0 (primap) software.Body length was measured from the anterior margin of the mandibles (in resting position) to the abdominal apex, the length of the forebody from the anterior margin of the mandibles to the posterior margin of the elytra, head length from the anterior margin of the frons to the posterior constriction of the head, elytral length at the suture from the apex of the scutellum to the posterior margin of the elytra (at the suture), and the length of the aedeagus from the apex of the ventral process to the base of the aedeagal capsule.The "parameral" side (i.e., the side where the sperm duct enters) is referred to as the ventral, the opposite side as the dorsal aspect.
3. New species and additional records of Lathrobium
Etymology: This species is dedicated to Tim Struyve, who collected the type specimens.
Description: Body length 9.5-10.5 mm; length of forebody 4.7-4.9mm.Habitus as in Fig. 1.Coloration: head, pronotum, and abdomen blackish; elytra dark-reddish, anteriorly more or less distinctly, narrowly and diffusely darker; legs reddish; antennae brown to dark-brown.Head (Fig. 2) oblong, 1.05-1.10times as long as broad; posterior angles broadly convex in dorsal view, nearly obsolete; punctation moderately coarse, dense in lateral and posterior portions, distinctly sparser in median dorsal portion; interstices narrower than diameter of punctures in lateral and posterior dorsal portions, with shallow microsculpture.Eyes weakly projecting from lateral contours of head, 0.25-0.30times as long as distance from posterior margin of eye to neck.Antenna (Fig. 3) approximately 2.5 mm long.Pronotum (Fig. 2) approximately 1.2 times as long as broad and 1.02-1.06times as broad as head; punctures of somewhat variable size, partly as coarse as that of head, partly finer, less dense than punctation in lateral and posterior portions of head; impunctate midline moderately broad; interstices without microsculpture.Elytra (Fig. 2) approximately 0.9 times as long as pronotum; punctation dense, less defined than that of pronotum.Hind wings present, shallow and moderately dense; inter-stices without microsculpture.Protarsomeres I-IV with weakly pronounced sexual dimorphism.Abdomen narrower than elytra; punctation fine and dense; posterior margin of tergite VII with palisade fringe; tergite VIII with sexual dimorphism.: protarsomeres I-IV strongly dilated (Fig. 1); tergite VIII with convex posterior margin; sternite VII (Fig. 4) strongly transverse, with impression of subtriangular shape in postero-median portion, this impression with very weakly modified (slightly shorter) setae, posterior margin weakly concave; sternite VIII (Fig. 5) transverse, with extensive, but shallow postero-median impression, posteriorly without pubescence in the middle, posterior margin broadly concave; aedeagus (Figs 6-9) approximately 2.2 mm long; ventral process long and slender, basally with three pronounced carinae and moderately bulging in lateral view, apically acute, and subapically with distinct tooth; dorsal plate with large and distinctly sclerotized apical portion with a median dorsal carina, without evident basal portion; internal sac with a pair of dark membranous structures apically extending into sclerotized spear-shaped processes and with a median dark membranous structure.: protarsomeres I-IV strongly dilated, only slightly less so than in male; posterior margin of tergite VIII truncate; sternite VIII (Fig. 10) longer than tergite VIII, weakly oblong, posterior margin distinctly truncate in the middle; tergite IX (Fig. 11) with long and undivided antero-median portion and moderately short posterolateral processes; tergite X (Fig. 11) short, 0.75 times as long as antero-median portion of tergite IX.
Comparative notes: Based on the similar modifications of the aedeagus (ventral process long and slender, basally with carinae and strongly bulging in lateral view, apically acute, and subapically with distinct tooth; dorsal plate of similar shape and with median dorsal carina), the similar male secondary sexual characters (particularly the shapes of sternites VII and VIII), as well as the highly similar female secondary sexual characters, L. struyvei is undoubtedly closely allied to L. dimidiati penne Bernhauer, 1910 (distributed from Middle Asia to the Russian Far East, doubtfully reported also from the Caucasus and Ukraine) and L. bernhaueri Koch, 1937(and its presumed junior synonym L. tichomirovae Coiffait, 1981; distributed in the Caucasus region).It differs from both by the shape (posterior margin only weakly concave) and chaetotaxy of the male sternite VIII and by the shape of the aedeagus (ventral process less bulging in lateral view).It is additionally distinguished from L. dimidiatipenne by the longer and more slender apical portion of the ventral process of the aedeagus in lateral view.

Distribution and natural history:
The type locality is situated in Ciudad Real, Castilla-La Mancha, Spain.The type material was sifted from moist litter near a stream (Struyve pers.comm.).

Comment:
The distribution of L. marani is confined to Middle Asia, where it is one of the more common species of the genus.

Comment:
The above material was collected at the type locality.

Comment:
The above specimens were collected near the type locality.

Comment:
The original description is based on three specimens collected in a nearby locality at an altitude of 3700 m (Assing 2012).

Etymology:
The specific epithet (adjective) is derived from the name of the pass where the type locality is situated.
Description: Small species; body length 5.6 mm; length of fore body 2.8 mm.External characters (Fig. 12) as in the closely related L. spinosissimum Assing, 2012.: protarsomeres I-IV strongly dilated; tergite VIII with truncate posterior margin; sternite VII (Fig. 13) 1.6 times as broad as long, with shallow and extensive posteromedian impression, this impression with a cluster of numerous moderately modified stout black setae, posterior margin weakly concave; sternite VIII (Fig. 14) weakly transverse, 1.07 times as broad as long, with long median impression, this impression with numerous moderately modified stout black setae, posterior excision small and of nearly semi-circular shape; aedeagus (Fig. 15) 1.0 mm long; ventral process tapering apicad and apically acute; dorsal plate with long and apically somewhat hooked apical portion (lateral view) and with short lamellate basal portion; internal sac with several large and more or less distinctly curved spines.: unknown.
Comparative notes: Based on the male sexual characters, particularly on the similar modifications of the aedeagus (shapes of ventral process and of dorsal plate; internal sac with several long and curved sclerotized spines), L. kiruense is most closely related to L. spinosissimum of the L. emodense group, from which it is distinguished only by the slightly more extensive clusters of slightly longer setae on the male sternites VII and VIII, by the slightly differently shaped posterior excision of the male sternite VIII, by some differences in the shape of the aedeagus (ventral process apically slightly less strongly tapering and basally slightly more distinctly curved), and especially in the shapes of the internal structures of the aedeagus (L.spinosissimum: apical internal structures apically abruptly curved).Except for the shapes of the internal structures of the aedeagus, the observed differences are slight, but nevertheless interpreted as interspecific variation.For illustrations of L. spinosissi mum see Assing (2012).

Distribution and natural history:
The type locality is situated in the southeastern Annapurna range, some 20 km to the north-northeast of Pokhara in Central Nepal.The slightly teneral holotype was collected at an altitude between 3800 and 4200 m.

Lathrobium lamjunense Assing, 2012
Material examined: Nepal: Comparative notes: Primarily based on the nearly unmodified pubescence of the male sternites VII and VIII, as well as on the dorso-ventrally flattened aedeagus with a long membranous structure in the internal sac, L. undosum is tentatively assigned to the L. discissum group, which previously included three described species from eastern Nepal and West Bengal.However, unlike the previously described representatives of this group, the aedeagus of L. undosum has a long dorsal plate.This species is readily distinguished from the species of all other Himalayan species groups by the absence of microsculpture on the head and by the distinctive morphology of the aedeagus.

Distribution and natural history:
The type locality is situated in Solu Khumbu, eastern Nepal, some 120 km to the east of Kathmandu.The holotype was collected at an altitude between 3500-3800 m.

Comment:
The above females most likely represent an undescribed species of the L. nepalense group.

Species groups
Primarily based on the male and female sexual characters, the six species recorded from East Yunnan are attributed to three species groups: Four species (L.crenatum, L. rostratum, L. tricarina tum, L. laciniatum), all of them distributed in the region to the north of Kunming, belong to the L. tentaculatum group, which previously included only L. tentaculatum Assing, 2013 from the Ailao Shan.The distributions of the species of this group are illustrated in Map 2. They share an aedeagus of derived morphology (more or less distinctly asymmetric; dorso-ventrally flattened; ventral process more or less deeply excised apically; basal portion very small; dorsal plate short and broad; internal structures absent, except for the ring-shaped structure), similar external characters (robust black body with strongly transverse elytra and a rather broad and weakly oblong pronotum; large eyes; similar punctation), a similar morphology of the female tergites IX and X (antero-median portion very short and with suture; tergite X very long and flat), and a mostly sexually dimorphic, posteriorly more or less distinctly angled tergite VIII.The L. daweianum group includes only a single species, L. daweianum, from the Dawei Shan in southeastern Yunnan (Map 2).It shares the long, slender, and strongly curved ventral process of the aedeagus and the morphol-ogy of the female tergite IX (anteriorly broadly undivided) with species of the L. curvatissimum group, which are distributed in northwestern Yunnan and Sichuan, but it is distinguished from them by much smaller body size, a more slender body (oblong head; much more oblong pronotum), the presence of massive internal spines in the internal sac of the aedeagus, a flat female tergite X, and the presence of a large black internal structure in the female segment IX.The L. coadultum group, which too is represented by a single species, L. coadultum, from the Dawei Shan (Map 2), is constituted above all by conspicuous and unique modifications of the female segments IX and X, which have not been observed in any other species or species group of the genus: tergite IX (including the postero-lateral processes) and tergite X are completely fused without so much as traces of sutures, thus forming a single oblong and posteriorly tapering plate with a pair of needle-shaped posterior processes and extending far beyond the apices of the hemisternites IX.In addition, this group is characterized by pronounced microsculpture on the head, the presence of strongly modified setae on the male sternites VII and VIII, and by a slender aedeagus with a long and conspicuously acute ventral process and with two long sclerotized spines in the internal sac.
Comment: This recently described species is endemic to the Haba Shan (Assing 2013c).
Comment: This species is rather common in the southern Diancang Shan, where it has been recorded at altitudes of 2600-4060 m (Assing 2013c).

Etymology:
The specific epithet is an adjective derived from the Latin noun crena (notch) and alludes to the profoundly notched apex of the aedeagus.
Description: Species of moderate size, without evident sexual size dimorphism; body length 7.5-9.0mm; length of fore body 3.7-4.0mm.Habitus as in Fig. 21.Coloration: body black; legs dark-brown, with the proand mesotibiae paler brown and the tarsi yellowish to yellowish-brown; antennae yellowish-red to reddish.Head (Fig. 22) weakly transverse, 1.01-1.06times as broad as long, usually weakly dilated behind eyes; punctation moderately coarse and moderately sparse, in median dorsal portion sparse; interstices with distinct microreticulation, on average slightly broader than dia meter of punctures in lateral and posterior dorsal portions, much broader in median dorsal portion.Eyes weakly convex, weakly projecting from lateral contours of head and rather large, approximately half as long as postocular region in dorsal view and composed of significantly more than 50 ommatidia.Antenna 2.0-2.2mm long.Pronotum (Fig. 22) rather broad, 1.15-1.20 times as long as broad and 1.07-1.10times as broad as head; punctation similar to that of head; impunctate midline moder ately broad; interstices without microsculpture.Elytra (Fig. 22) short and broad, approximately : protarsomeres I-IV dilated, but slightly less so than in male; posterior margin of tergite VIII distinctly angled in the middle (more so than in male); sternite VIII (Fig. 28) approximately 1.1 times as long as broad and with strongly convex posterior margin; tergite IX (Fig. 29) with very short and divided antero-median portion and with slender postero-lateral processes; tergite X (Fig. 29) flattened and very long, approximately ten times as long as antero-median portion of tergite IX.
Comparative notes: Among the species previously recorded from Yunnan, L. crenatum is most similar -and based on the similarly derived morphology of the aedeagus most closely related -to L. tentaculatum Assing, 2013 from the Ailao Shan, previously the sole representative of the L. tentaculatum group.Both species are externally similar (moderately large and robust black body with strongly transverse elytra and a rather broad pronotum; large eyes; similar punctation), a similar morphology of the female tergites IX and X (anteromedian portion very short and with suture; tergite X very long), a posteriorly angled tergite VIII, and particularly an aedeagus of derived morphology (distinctly asymmetric; dorso-ventrally flattened; ventral process deeply excised apically; basal portion very small; dorsal plate short and broad; internal structures absent, except for the ring-shaped structure).Lathrobium crenatum is distinguished from L. tentaculatum by smaller size, by the shapes and chaetotaxy of the male sternites VII and VIII, as well as by the shape of the aedeagus (L.tentaculatum: ventral process apically extending into a pair of long and slender processes).For illustrations of L. tentaculatum see Assing (2013c).

Distribution and natural history:
The species was discovered in a mountain to the northeast of Dongchuan in northeastern Yunnan.The specimens were sifted from pine needles between rocks in a secondary pine forest and from litter on a scree slope with bushes and herbs at an altitude of 2670 m.

Etymology:
The specific epithet is an adjective derived from the Latin noun rostrum (beak) and alludes to the shape of the apex of the aedeagus.
Description: Species of moderate size, without evident sexual size dimorphism; body length 6.5-8.2 mm; length of fore body 3.3-3.7 mm.Habitus as in Fig. 30.Coloration: body black; legs brown, with the profemora and often also the meso-and metafemora dark-brown and with the tarsi yellowish-brown; antennae reddish.Head (Fig. 31) weakly transverse, : protarsomeres I-IV dilated, but somewhat less so than in male; posterior margin of tergite VIII distinctly angled in the middle (more so than in male); sternite VIII (Fig. 77) approximately 1.1 times as long as broad and with strongly convex posterior margin; tergite IX (Fig. 78) with short antero-median portion with median suture and with slender postero-lateral processes; tergite X (Fig. 78) flattened and very long, approximately five times as long as antero-median portion of tergite IX.

Comparative notes:
As can be inferred from the external and sexual characters, particularly from the similarly modified aedeagus, L. rostratum, too, belongs to the L. tentaculatum group.It is distinguished from L. crenatum by slightly smaller body size, distinctly smaller eyes, the shapes and chaetotaxy of the male sternites VII and VIII, the shape of the aedeagus, and by the long antero-median portion of the female tergite IX.
Distribution and natural history: The species was found in two geographically close localities to the northeast of Kunming.The specimens were sifted from litter in a mixed broad-leaved forest with scattered pine trees and in a mixed forest with alder, oak, and pine at altitudes of 2290 and 2320 m, respectively.Some of the paratypes are teneral.

Etymology:
The specific epithet (Latin, adjective) alludes to the presence of three carinae on the ventral process of the aedeagus.: protarsomeres I-IV dilated, but slightly less so than in male; posterior margin of tergite VIII distinctly angled in the middle (more so than in male); sternite VIII (Fig. 43) approximately 1.1 times as long as broad and with strongly convex posterior margin; tergite IX (Fig. 44) with short antero-median portion with median suture, and with slender postero-lateral processes; tergite X (Fig. 44) flattened and very long, approximately six times as long as antero-median portion of tergite IX.
Comparative notes: Based on the external and sexual characters, particularly on the modifications of the aedeagus, L. tricarinatum belongs to the L. tentacula tum group.It is distinguished from both L. crenatum and L. rostratum by the morphology of the aedeagus and by the smaller posterior excision of the male sternite VIII, from the geographically close L. crenatum additionally by smaller body size, slightly smaller eyes, the different shape and chaetotaxy of the male sternite VII, and by the slightly longer antero-median portion of the female tergite IX.

Distribution and natural history:
The type locality is situated near the Sedan Snow Mountain Scenic Resort in the mountains to the West of Dongchuan, northeastern Yunnan.The specimens were sifted from litter, moss, and the roots of herbs in a terraced secondary pine forest at an altitude of 2620 m.One of the paratypes is teneral.
Lathrobium laciniatum spec.nov.: protarsomeres I-IV nearly as dilated as in male; sternite VIII (Fig. 52) approximately 1.15 times as long as broad and with strongly convex posterior margin; tergite IX (Fig. 53) with short antero-median portion with median suture and with slender postero-lateral processes; tergite X (Fig. 53) flattened and very long, nearly ten times as long as antero-median portion of tergite IX.
Comparative notes: Based on the external and sexual characters, particularly on the modifications of the aedeagus, L. laciniatum clearly belongs to the L. tentacu latum group.It is distinguished from other species of this group by the smaller, more symmetric, and differently shaped aedeagus, by the shallower posterior excision of the male sternite VIII, and by the more slender body (head oblong; pronotum more oblong; antennae relatively longer).Based on the similar modifications of the aedeagus (presence of three ventral carinae; apices of ventral process of similar shape), L. laciniatum is most closely allied to L. tricarinatum from the environs of Dongchuan.

Distribution and natural history:
The type locality is situated to the west-northwest of Wuding in eastern Yunnan.The specimens were sifted from litter at the margin of a mixed forest with alder, pine, and bushes at an altitude of 2390 m.Numerous paratypes are teneral.

Etymology:
The specific epithet is an adjective derived from the name of the mountain where the type locality is situated.
Description: Small species of slender habitus, without evident sexual size dimorphism; body length 5.5-7.0 mm; length of fore body 2.6-2.8mm.Habitus as in Fig. 54.Coloration: head dark-brown; pronotum and elytra reddish-brown to brown, with the suture and the posterior margins of the elytra reddish; abdomen blackish-brown to blackish, with segments VIII-X reddish; legs reddish-yellow; antennae reddish.Head (Fig. 55   : protarsomeres I-IV moderately dilated, distinctly less so than in male; tergite VIII with strongly convex posterior margin; sternite VIII (Fig. 60) elongated, approximately 1.35 times as long as broad and with strongly convex posterior margin; tergite IX (Fig. 61) with long antero-median portion without median suture and with moderately slender postero-lateral processes; tergite X (Fig. 61) flattened, only slightly longer than antero-median portion of tergite IX; segment IX (Fig. 62) with a conspicuous large black internal structure.
Comparative notes: Lathrobium daweianum is readily distinguished from all other Lathrobium species recorded from eastern Yunnan by much smaller size, paler coloration, the more slender head with smaller eyes, the much more slender pronotum, the denser punctation of the abdominal tergite VII, the pronounced sexual dimorphism of the protarsi and the abdominal tergite VIII, the completely different morphology of the aedeagus, the much more oblong female sternite VIII, and the different morphology of the female tergites IX and X (tergite IX without median suture and with shorter postero-lateral processes; tergite X shorter).The species cannot be assigned to any of the species groups previously known from Yunnan and adjacent provinces without difficulty.Based on the morphology of the female tergites IX and X, on the general morphology of the aedeagus, and on the absence of an anterior cluster of gland openings on the male sternite VIII, the only eligible candidates would be the L. curvatissimum, the L. bihamulatum, and the L. desectum groups.The latter two groups can be ruled out, too, as L. daweianum does not share the synapomorphies that constitute these groups.The new species shares the long, slender, and strongly curved ventral process of the aedeagus with species of the L. curvatissimum group, which are distributed in northwestern Yunnan and Sichuan, but it is distinguished from them by much smaller body size, a more slender body (oblong head; much more oblong pronotum, etc.), the presence of massive internal spines in the internal sac of the aedeagus, a flat female tergite X, and the presence of a large black internal structure in the female segment IX.Consequently, L. daweianum is attributed to a species group of its own.

Etymology:
The specific epithet is the past participle of the Latin verb coadulescere (to grow together) and alludes to the fused female tergites IX and X.
Description: Species of moderate size, without evident sexual size dimorphism; body length 7.0-7.5 mm; length of fore body 3.5-3.6mm.Habitus as in Fig. 63.Coloration: head and pronotum blackish-brown to blackish; elytra dark-brown to blackish-brown, with the posterior portion slightly paler; abdomen dark-brown to blackishbrown; legs and antennae dark-reddish.Head (Fig. 64) weakly oblong, approximately 1.05 times as long as broad, lateral contours behind eyes distinctly convex; punctation rather dense and coarse in lateral, anterior, and posterior dorsal portions, sparse and finer in median dorsal portion; interstices with conspicuous microreticulation rendering the head nearly matt, on average approximately as broad as diameter of punctures in lateral and posterior dorsal portions (Fig. 65).Eyes weakly convex, weakly projecting from lateral contours of head and small, approximately one-fourth as long as postocular region in dorsal view and composed of slightly more than 50 ommatidia.Antenna 2.0-2.1 mm long.Pronotum (Fig. 64) moderately slender, 1.27-1.28times as long as broad and 1.08-1.10times as broad as head; punctation slightly coarser than that of head; impunctate midline rather broad; interstices without microsculpture.
Elytra (Fig. 64) short, 0.51-0.52times as long as pronotum, not distinctly dilated posteriad; humeral angles moderately marked; punctation moderately dense and shallow, weakly defined; interstices without microsculpture.Hind wings completely reduced.Protarsomeres I-IV with weak sexual dimorphism.Abdomen approximately 1.1 times as broad as elytra; punctation fine, rather dense on tergites III-VII, only slightly less dense on tergite VII than on tergite VI; interstices with shallow transverse microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII with pronounced sexual dimorphism.
: protarsomeres I-IV moderately strongly dilated; tergite VIII with weakly convex posterior margin; sternite VII (Fig. 70) strongly transverse, approximately 1.6 times as broad as long, with rather pronounced and extensive postero-median impression of triangular shape, this impression with a cluster of strongly modified short and stout black setae, median portion with numerous gland openings (Fig. 71), posterior margin weakly concave; sternite VIII (Fig. 72) distinctly oblong, 1.15 times as long as broad, with pronounced median impression in posterior half, this impression with numerous strongly modified short and stout black setae, posterior margin strongly convex, in the middle with small and broadly V-shaped excision; aedeagus (Figs 66-69) 1.7 mm long, slender, and nearly symmetric; ventral process conspicuously long, slender, and apically very acute; dorsal plate long, sclerotized, lamellate, and apically concave in dorsal view, without distinctly separated basal portion; internal sac with two very long and slender sclerotized spines.: protarsomeres I-IV moderately strongly dilated, only very slightly less so than in male; tergite VIII (Fig. 73) with posterior margin conspicuously acutely produced in the middle; sternite VIII (Fig. 74) elongated, approximately 1.3 times as long as broad and with strongly convex posterior margin; segments IX and X remarkably modified (Figs 75-76): tergites IX (including the posterolateral processes) and X completely fused and forming one long, posteriorly distinctly tapering plate without any sutures whatsoever, apex of this plate reaching far beyond apices of hemi-sternites IX, with two short needle-shaped processes.
Comparative notes: Lathrobium coadultum is distinguished from all other Lathrobium species not only by the distinctive male sexual characters, but also by the shape of the female tergite VIII and above all by the remarkably modified, completely fused female tergites IX and X.Such modifications are unknown from any other species of the genus, suggesting that L. coadultum represents a distinct phylogenetic lineage.This species is additonally separated from other congeners recorded from eastern Yunnan by the more pronounced microreticulation of the head and by the gland openings in the median portion of the male sternite VII.

Etymology:
The species is dedicated to Vasily Grebennikov (currently Ottawa), who collected the type series, also in appreciation of his merits in discovering numerous other novelties in China.
Description: Species of moderate size and with moderately pronounced sexual size dimorphism; body length 7.5-8.5 mm (), 6.2-7.5 mm (); length of fore body 3.6-3.7 mm (), 3.1-3.4mm ().Coloration: body brown to dark-brown; legs reddish to reddish-brown; antennae dark-reddish.Head (Fig. 79) 1.00-1.05times as long as broad, widest behind eyes; punctation moderately coarse and moderately dense, slightly less dense in median dorsal portion; interstices with shallow, but distinct microreticulation.Eyes flat, not projecting from lateral contours of head, and small, approximately one-fourth as long as postocular region in dorsal view, or slightly longer, and composed of fewer than 50 ommatidia.Antenna 1.8-1.9mm () or 1.5-1.7 mm () long.Pronotum (Fig. 79) moderately slender, approximately 1.3 times as long as broad and as broad as head; punctation similar to that of head; impunctate midline rather narrow; interstices without microsculpture.Elytra (Fig. 79) approximately 0.55 times as long as pronotum, weakly dilated posteriad; humeral angles moderately marked; punctation shallow and moderately dense; interstices without microsculpture.Hind wings completely reduced.Protarsomeres I-IV with pronounced sexual dimorphism.Abdomen approximately 1.1 times as broad as elytra; punctation fine and moderately dense, gradually becoming less dense towards posterior tergites; interstices with shallow transverse microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII with very weakly pronounced sexual dimorphism.: protarsomeres I-IV strongly dilated; tergite VIII with weakly convex, nearly truncate posterior margin; sternite VII (Fig. 80) strongly transverse, approximately 1.65 times as broad as long, with rather extensive and moderately pronounced postero-median impression of triangular shape, this impression with a cluster of rather weakly modified black setae, posterior margin broadly concave; sternite VIII (Fig. 81) transverse, approximately 1.1 times as broad as long, narrowly impressed along middle, middle of this impression without setae, on either side of middle with dense moderately modified setae, posterior margin with small median excision; aedeagus (Figs 82-85) 1.30-1.35mm long, nearly symmetric; ventral process apically bent and acute in lateral view; dorsal plate distinctly sclerotized, with long and broad apical portion with median carina (dorsal view) and with moderately short basal portion; internal sac with moderately sclerotized structures, but without distinct spines.: protarsomeres I-IV dilated, but much less so than in male; sternite VIII (Fig. 86) approximately 1.1 mm long and 1.25 times as long as broad, posterior margin strongly and convexly projecting in the middle; tergite IX (Fig. 87) with long and undivided median portion and with moderately slender postero-lateral processes; tergite X (Fig. 87) moderately convex in cross-section, 1.10-1.15times as long as antero-median portion.

Comparative notes:
As can be inferred from the similar modifications of the male and female sexual characters, L. grebennikovi belongs to the L. varisternale group (see Assing 2013a), which previously included 14 species distributed in the Qinling Shan and adjacent mountain ranges (Assing 2013a;Peng et al. 2013).It is distinguished from all the species of this group primarily by the morphology of the aedeagus.The latter is most similar to that of L. inflexum Assing, 2013 from a mountain range to the southeast of Longnan in southern Gansu.From this species, L. grebennikovi is additionally distinguished by slightly larger body size, the sexual size dimorphism, the more pronounced clusters of modified setae on the male sternites VII and VIII, the absence of a distinct median concavity of the posterior margin of the male sternite VII, the larger aedeagus with a differently shaped ventral process and with a distinctly sclerotized basal portion of the dorsal plate, the differently shaped female sternite VIII, and the longer female tergite X (L.inflexum: female tergite X shorter than antero-median portion of tergite IX).For illustrations of L. inflexum and other species of the L. vari sternale group see Assing (2013a) and Peng et al. (2013).

Distribution and natural history:
The type locality is situated in the northern Qinling Shan in southern Shaanxi.The type specimens were sifted together with L. brevitergale at altitudes between 1700 and 2200 m.

Etymology:
The specific epithet is an adjective composed of the Latin adjective calvus (bald, bare) and the past participle of the Latin verb sulcare (to furrow).It alludes to the absence of pubescence in the median impressions of the male sternites VII and VIII.
Description: Species of moderate size; body length 7.8 mm; length of fore body 3.7 mm.Coloration: forebody dark-brown; elytra brown; abdomen dark-brown with paler apex; body brown to dark-brown; legs and antennae reddish.Head (Fig. 88 : protarsomeres I-IV strongly dilated; tergite VIII with weakly convex posterior margin; sternite VII (Fig. 89) strongly transverse, approximately 1.7 times as broad as long, with rather extensive and pronounced median impression, this impression broadly without setae along the middle and postero-laterally with a cluster of weakly modified setae, posterior margin distinctly concave in the middle; sternite VIII (Fig. 90) weakly transverse, approximately 1.05 times as broad as long, with narrow and long median impression, this impression without setae, on either side of this impression with an oblong and rather long cluster of weakly modified dark setae, posterior excision distinct and V-shaped; aedeagus (Figs 91-92) nearly 1.5 mm long and symmetric in ventral view; ventral process smoothly curved, slender, and apically acute in lateral view; dorsal plate with long lamellate apical portion and with distinctly shorter lamellate basal portion; internal sac with membranous structures of characteristic shape in lateral view, the dorsal ones shaped like an inverted comma.: unknown.
Comparative notes: Like the preceding species, L. calvi sulcatum belongs to the L. varisternale group.Among the species of this group, the male sexual characters (chaetotaxy of sternites VII and VIII; morphology of the aedeagus) are most similar to those of L. breviloba tum Assing, 2013, from which L. calvisulcatum differs by the more transverse male sternite VII with sparser clusters of less modified setae and without setae in the antero-median portion, by a male sternite VIII with a distinctly deeper posterior excision and with more extensive clusters of modified setae, and by the morphology of the aedeagus (shapes of ventral process, dorsal plate, and internal structures).For illustrations of L. brevilobatum see Assing (2013a).
Distribution and natural history: The type locality is situated in the Qinling Shan to the south of Xi'an in southern Shaanxi.The slightly teneral holotype was sifted together with L. brevitergale at an altitude between 2000 and 2600 m.
Comment: This species is endemic to the Emei Shan, where it was previously recorded at altitudes of 1800-2500 m (Assing et al. 2013).
Comment: Like L. iunctum, L. coniunctum is endemic to the Emei Shan, where it was previously recorded at altitudes of 1700-2310 m (Assing et al. 2013).
Comment: This endemic of the Emei Shan apparently lives at lower altitudes; it was previously found at 1100 m (Assing et al. 2013).
Comment: This species is endemic to the Gongga Shan and was previously found at altitudes of 2750-3350 m (Assing 2013b).

Etymology:
The specific epithet (Latin, adjective) alludes to the abruptly angled ventral process of the aedeagus (lateral view).
Comparative notes: Based on the similar modifications of the male and female sexual characters, this species is undoubtedly most closely related to L. hailuogouense, which too is endemic to the Gongga Shan.It differs from this species only by the more extensive and more distinct postero-median cluster of modified setae on the male sternite VII and by the morphology of the aedeagus (L.hailuogouense: ventral process less strongly narrowed

Etymology:
The specific epithet (Latin, adjective) alludes to the shape of the conspicuous process (lateral view) at the base of the ventral process of the aedeagus.
Description: Species of rather large size; body length 11.0 mm; length of fore body 5.1 mm.Habitus as in Fig. 102.Coloration: body dark-brown; legs and antennae dark-reddish.Head (Fig. 103) approximately as long as broad, weakly dilated behind eyes; punctation not very coarse, rather dense in lateral, anterior, and posterior dorsal portions, sparser in median dorsal portion; interstices with very shallow, barely noticeable microreticulation, on average approximately as broad as diameter of punctures in lateral and posterior dorsal portions.Eyes weakly convex, not projecting from lateral contours of head, and small, approximately one-fifth as long as postocular region in dorsal view and composed of slightly more than 50 ommatidia.Antenna 2.9 mm long.Pronotum (Fig. 103) moderately slender, 1.29 times as long as broad and 1.02 times as broad as head; punctation similar to that of head; impunctate midline moderately broad; interstices without microsculpture.Elytra (Fig. 103) short, 0.49 times as long as pronotum, not distinctly dilated posteriad; humeral angles moderately marked; punctation rather dense and defined; interstices without microsculpture.Hind wings completely reduced.Abdomen approximately 1.05 times as broad as elytra; punctation fine, rather dense on tergites III-VI, sparser on tergite VII; interstices with shallow transverse microsculpture; posterior margin of tergite VII without palisade fringe.: protarsomeres I-IV strongly dilated; tergite VIII with weakly convex posterior margin; sternite VII (Fig. 104) moderately strongly transverse, approximately 1.4 times as broad as long, with rather pronounced postero-median impression of triangular shape, this impression with a cluster of modified stout black setae, posterior margin broadly concave, in the middle somewhat more distinctly concave; sternite VIII (Fig. 105) as long as broad, with pronounced median impression in posterior half, this impression with conspicuously dense modified stout black setae, posterior excision broadly V-shaped, its depth approximately one-seventh the length of sternite; aedeagus (Figs 106-109) 1.9 mm long, strongly asymmetric, with small basal portion, and of remarkably modified morphology; ventral process strongly asymmetric, of very distinctive shape, partly fused with the asymmetric dorsal plate, and at base with conspicuous erect process; internal sac with a very long, slender, and basally bifid sclerotized spine (Fig. 110) and with a membranous ringshaped structure.: unknown.
Comparative notes: Based on the morphology of the aedeagus (strongly asymmetric; small basal portion; internal sac with a long sclerotized spine) and on the male secondary sexual characters, L.

Etymology:
The specific epithet is the past participle of the Latin verb volvere (to roll) and alludes to the shape of the internal structure of the aedeagus.
Description: Body length 6.5-7.5 mm; length of forebody 3.4-3.6mm.Habitus as in Fig. 126.Coloration: body blackish-brown to blackish; legs yellowish-brown; antennae dark-reddish.Head (Fig. 127) weakly transverse, 1.02-1.04times as broad as long; punctation moderately coarse and moderately dense, sparser in median dorsal portion; interstices with distinct microreticulation.Eyes weakly projecting from lateral contours of head, approximately one-third as long as postocular region in dorsal view, or even shorter, and composed of approximately 50 ommatidia.Antenna approximately 1.8 mm long.Pronotum (Fig. 127) approximately 1.2 times as long as broad and about as broad as head; punctation similar to that of head, but somewhat sparser; impunctate midline moderately broad; interstices without microsculpture.Elytra (Fig. 127) approximately 0.55 times as long as pronotum, weakly dilated posteriad; humeral angles weakly marked; punctation shallow and moderately dense; interstices without microsculpture.Hind wings completely reduced.Protarsomeres I-IV with pronounced sexual dimorphism.Abdomen distinctly broader than elytra; punctation fine and moderately dense, density decreasing towards posterior tergites; posterior margin of tergite VII without palisade fringe; tergite VIII with sexual dimorphism.: protarsomeres I-IV strongly dilated; posterior margin of tergite VIII truncate; sternite VII (Fig. 128) strongly transverse, with impression of subtriangular shape in postero-median portion, this impression with moderately dense and moderately modified black setae, posterior margin distinctly concave in the middle; sternite VIII (Fig. 129) weakly transverse and longitudinally impressed in postero-median portion, posterior excision small and U-shaped, on either side of posterior excision weakly produced, posterior portion with dense stout black setae; aedeagus (Figs 130-131) 1.7 mm long and symmetric; ventral process long, weakly curved in lateral view, apically acute, with a pronounced median carina ventrally; dorsal plate with a long, distinctly sclerotized, dorsally weakly excavate, and apically dentate apical portion (Fig. 132) and with a shorter lamellate basal portion; internal sac with a broad, curved (cross-section), and moderately sclerotized structure.
: protarsomeres I-IV moderately dilated, distinctly less so than in male; posterior margin of tergite VIII convex; sternite VIII (Fig. 133) longer than tergite VIII, convexly produced posteriorly; tergite IX (Fig. 134) with very long and undivided antero-median portion and short postero-lateral processes; tergite X (Fig. 134) short, little more than one-third as long as antero-median portion of tergite IX.
Comparative notes: Based on the similarly modified male sternites VII and VIII, as well as the similar general morphology of the aedeagus, particularly the presence of an internal structure of similar general shape, L. volu tum is very closely allied to the syntopic L. scaphiforme, from which it differs by distinctly smaller size, the more slender habitus, the less pronounced median concavity of the male sternite VII, the different shape and chaetotaxy of the male sternite VIII, the different shapes of the ventral process and the dorsal plate of the aedeagus, the relatively longer antero-median portion of the female tergite IX, and the shorter female tergite X.

Distribution and natural history:
The type locality is situated near Kawai (northern Honshu: Iwate Prefecture) at an altitude of 600-700 m.The specimens were collected together with the holotype of L. scaphiforme.

Etymology:
The specific epithet is an adjective derived from the Latin noun trabs (beam) and alludes to the massive dorsal plate of the aedeagus.
Description: Size subject to distinct sexual dimorphism; body length 8.2-8.8 mm (), 6.8-8.0 mm (); length of forebody 4.1 mm (), 3.4-3.7 mm ().Habitus as in Fig. 135.Coloration: body blackish-brown; legs yellowish-red; antennae reddish.Head (Fig. 136) approximately as broad as long; punctation moderately coarse and sparse, very sparse in median dorsal portion; interstices with distinct microreticulation.Eyes weakly projecting from lateral contours of head, approximately half as long as postocular region in dorsal view, or nearly so, and composed of > 50 ommatidia.Antenna 2.4 () or 2.0-2.1 () mm long.Pronotum (Fig. 136) approximately 1.2 times as long as broad and 1.10-1.14times as broad as head; punctation similar to that of head; impunctate midline moderately broad; interstices without microsculpture.straight in dorsal view; punctation similar to that of head; interstices without microreticulation along midline, with very shallow microreticulation laterally; impunctate median band narrow, not reaching posterior margin.Elytra (Fig. 143) long and large, 1.05 times as long and more than 1.5 times as broad as pronotum; punctation dense, distinct, coarser than that of pronotum, and not distinctly seriate; interstices without microreticulation, glossy.Protarsomeres I-IV strongly dilated.Metatarsomere I shorter than II.Abdomen distinctly narrower than elytra, segments III-VI of subequal width; punctation dense and rather coarse on anterior tergites, gradually becoming finer and sparser towards abdominal apex; interstices with shallow microreticulation; posterior margin of tergite VII with palisade fringe.: sternite VII unmodified; sternite VIII (Fig. 146) distinctly oblong, 1.1 times as long as broad, posterior excision shallow and with noticeable angle in the middle, pubescence unmodified; aedeagus (Figs 147-148) small in relation to body size, 0.7 mm long; dorsal plate short and apically acute (Fig. 149); internal sac with plateshaped internal structure (Fig. 149).
Comparative notes: Using the key in Assing (2013e), E. edentulum would key out at couplet 3, together with E. qinlinganum Assing, 2013, from which it differs by the elevated postero-median dorsal portion of the head, the slightly more oblong antennomeres IV-X, the different shape of the pronotum (E.qinlinganum: lateral margin nearly parallel in dorsal view), the presence of shallow microsculpture on the pronotum, the less strongly dilated protarsomeres I-IV, and the distinctly smaller and differently shaped aedeagus.For illustrations of E. qinlinganum and other species of the genus see Assing (2013e).
Distribution and natural history: The type locality is situated in the Qinling Shan in southern Shaanxi.The holotype was sifted at an altitude between 1700 and 2200 m.
Species of moderate size, without evident sexual size dimorphism; body length 7.3-7.7 mm; length of fore body 3.3-3.5 mm.Habitus as in Fig.36.Coloration: body black; legs pale-brown, with the profemora darkbrown and with the tarsi yellowish-brown; antennae reddish. Description: The specific epithet is an adjective derived from the Latin noun lacinia (lobe) and alludes to the shapes of the two apices of the aedeagus.

Distribution and natural history:
The type locality is situated in the Dawei Shan Virgin Forest Park to the southeast of Pingbian in southeastern Yunnan, close to the border with Vietnam.Thus, L. daweianum and the syntopic L. coadultum represent the southernmost records of the genus in mainland China.The specimens were sifted from leaf litter in a primary subtropical broadleaved forest at an altitude of 2100 m, together with the types of L. coadultum.
, 1 : same data as holotype; 3 , 3 : "P.R. CHINA, Sichuan, NE slope Gongga Shan, Abdomen approximately 1.05-1.10timesasbroadaselytra; punctation fine and dense on tergites III-VII, only slightly less dense on tergite VIII; interstices with fine microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII without sexual dimorphism, posterior margin weakly convex.:protarsomeresI-IVstronglydilated; sternite VII (Fig.94) strongly transverse, approximately 1.6 times as broad as long, with moderately pronounced posteromedian impression of triangular shape, this impression with a cluster of modified stout black setae, posterior margin broadly concave, in the middle somewhat more distinctly concave; sternite VIII (Fig.95) distinctly transverse, approximately 1.2 times as broad as long, shallowly impressed and with dense weakly modified setae in postero-median portion, posterior excision not very deep and broadly V-shaped; aedeagus (Figs 96-99) approximately 2.0 mm long and slender, not distinctly asymmetric in ventral view; ventral process very long, slender, and apically acute, abruptly angled at apical third in lateral view; dorsal plate with strongly scle-rotized, long, strongly curved (lateral view) and apically acute apical portion and with short, weakly sclerotized, lamellate basal portion; internal sac with pair of long and weakly sclerotized structures.
Peng et al. (2012)angled at apical third, apex of ventral process shorter and less slender; apical portion of dorsal plate curved in apical half, in L. abruptum in basal half, in lateral view).For illustrations of L. hailuogouense seePeng et al. (2012).