A taxonomic revision of Tyrini of the Oriental region. V. Revision of the genus Lasinus Sharp, 1874 (Coleoptera, Staphylinidae, Pselaphinae)

Abstract The genus Lasinus Sharp, 1874 of the Pselaphodes complex of genera (Pselaphitae: Tyrini: Tyrina) is revised. The three so far known species, Lasinus mandarinus Raffray, 1890, Lasinus monticola Sawada, 1961 and Lasinus spinosus Sharp, 1874 are redescribed. Eight new species, Lasinus sinicus sp. n. from China, Lasinus mikado sp. n., Lasinus yamamotoi sp. n., Lasinus inexpectatus sp. n., Lasinus yakushimanus sp. n., Lasinus amamianus sp. n., Lasinus saoriae sp. n., and Lasinus okinawanus sp. n. from Japan, are described. And all species are illustrated. Lectotypes are designated for Lasinus mandarinus and Lasinus spinosus. An identification key to species of the genus Lasinus is provided.


Introduction
The genus Lasinus was erected by Sharp (1874) to accommodate his new species L. spinosus from Japan. Another new species, L. mandarinus was added by Raffray (1890) from the northern Vietnam. The last known species, L. monticola, was described from Japan by Sawada (1961) who also provided illustrations of aedeagi of the presumed L. spinosus. The genus was studied by the second author (Hlaváč 2003) and was included in the Pselaphodes complex of genera of the subtribe Tyrina, tribe Tyrini.
The purpose of this paper is the revision of the genus, the description of eight new species, as well as to provide a key for the identification of all species of the genus.

Materials and methods
Dry-mounted specimens were relaxed in warm water. Dissections were made using standard techniques, genitalia and small parts were mounted in Euparal or Canada balsam on acetate labels which are pinned together with the specimens. Leica S8APO microscope was used for the study. All photos were done by microscope Olympus SZ 61 with camera Olympus Colorview I. The width of head is measured through eyes.
Lectotype designation. Redescription of this species given below is based on four females deposited in MNHN having a status of syntypes. Raffray (1890) also mentioned four females in his original description. One female is here designated as lectotype, and three remaining females paralectotypes, in order to ensure the stability of nomenclature and provide a unique name-bearing type for Lasinus mandarinus.
Head elongate, about 1.15 times longer than wide, slightly longer than pronotum; median sulcus well-defined along whole length of head. Genae simple, without protuberance.
Antennae very long, about 2.3-2.4 mm; scapes about 5 times longer than pedicels, pedicels short, as long as wide; antennomeres III-VII subequal in length, slightly shorter than V; antennomeres VI-VIII about as long as pedicels; IX slender, 2.25 times longer than wide, 1.10 times as long as X; late about 1.6 times longer than wide; terminal segments 1.2 times as long as X and 1.6 times longer than wide.
Pronotum as long as wide, gibbose, with prominent lateral swellings before lateral foveae; lateral and median setose foveae well-defined; median sulcus originates in median fovea and almost reaching anterior margin of pronotum.
Legs long and slender; protrochanters with small apical spine; profemora with long spine before middle; mesotrochanters at apex with two spines, outer one fairly bigger; mesofemora with minuscule spine at basal third.
First visible abdominal tergite (IV) glabrous, slightly more than two times longer than second (V); short basal carinae well-defined, distance between carinae 0.4 of maximal tergal width.
Differential diagnosis. Lasinus mandarinus is close to L. sinicus by the pronotum with prominent lateral swellings before lateral foveae, but it differs from the latter by the proportion of antennomere X which is 1.6 times as long as wide.
Distribution. Vietnam (Tonkin, Ha Noi). Lectotype designation. Redescription of this species given below is based on one male and one female deposited in BMNH having a status of syntypes. Sharp (1874) mentioned three specimens in his original description. One male is here designated as lectotype, another female is paralectotype, in order to ensure the stability of nomenclature and provide a unique name-bearing type for Lasinus spinosus.
Head elongate, about 1.15 times longer than wide, slightly longer than pronotum; median sulcus visible on rostrum and on vertex reaching level of vertexal foveae. Genae with weak protuberance, covered with erected, dense golden setae.
Antennae about 2.02 mm long (Fig. 11); scapes long, about 3.7 times longer than pedicels; pedicels about 1.18 times shorter than antennomeres III; antennomeres IV and V as long as wide; antennomeres VI 1.22 times shorter than pedicels; antennomeres VII 1.25 times shorter than VI; antennomeres VIII about 1.27 times longer than and distinctly wider than VII; IX about 1.5 times longer than wide and about same length as terminal antennomeres, IX in male with small and shallow discoidal plate on apical half bearing small pore-like structure with one long seta, in female unmodified; antennomeres X quadrate, 1.5 times shorter than IX; terminal antennomeres 1.6 times longer than X and about 1.5 times longer than wide.
Pronotum about as wide as long, wrinkly, evenly rounded before lateral foveae; lateral and median setose foveae well-defined; median longitudinal sulcus very thin, but distinct.
Legs long and slender; protrochanters with large apical spine; profemora with long spine in middle of its length; mesotrochanters at apex with one small (male) or two (female) spines, in some cases one spine is slightly stronger; mesofemora with minuscule spine at basal third.
Abdomen slightly wider than elytra, first visible abdominal tergite (IV) finely punctate with dense and short golden setae, about 4 times as long as next tergite, basal carinae very short, distance between carinae 0.4 of maximal tergal width. Aedeagus (Fig. 20) 0.64 mm long; median lobe weakly narrowed apically, with short and large apical lobe; endophallus with two spines and one lamella; dorsal spine very big, enlarged at apex, forming large plate; ventral spine long, acute at apex; lamella small finely dentate in apical part; parameres short and slender, not overlapping apical lobe.
Differential diagnosis. Lasinus spinosus shares with L. monticola, L. mikado, L. inexpectatus, L. saoriae and L. yamamotoi the evenly rounded pronotal lateral margins, but differs from all of these species by the shape of the antennae and aedeagus.

Lasinus monticola
Head elongate, about 1.06 times longer than wide and as long as pronotum; median sulcus weakly defined along whole length of head. Genae with triangular, prominent protuberance, covered with erect, dense golden setae (Fig. 6).
Antennae about 2.23 mm long (Fig. 12); scapes long, about 4 times longer than pedicels; pedicels shortest, quadrate and as long as IV and V each; antennomeres III about 1.25 times longer than pedicels; antennomeres VI-VII subequal in length; VIII slightly shorter than VII; IX about 1.5 times longer than wide, with apical, nail-shaped protuberance on ventral side in male, in female unmodified; antennomeres X quadrate, 1.25 times shorter than IX; terminal antennomeres 1.5 times longer than X and about 1.5 times longer than wide.  Pronotum slightly longer than wide, wrinkly, evenly rounded before lateral foveae (Fig. 8); lateral and median setose foveae well-defined; median sulcus weakly-defined.
Legs long and slender; protrochanters with small apical spine; profemora with long spine before middle; mesotrochanters at apex with two (males) minuscule spines or three (females) spines, median one minuscule; mesofemora with minuscule spine at basal third.
Abdomen slightly wider than elytra, first visible tergite (IV) about 3 times as long as second (V), finely punctate with dense, very short golden setae ; basal carinae welldefined but very short, distance between carinae 0.5 of the maximal tergal width. Aedeagus (Fig. 21) 0.66 mm long; median lobe weakly narrowed apically, with short and large apical lobe, curved downwards in middle; endophallus with two spines and one large lamella; dorsal spine large, enlarged in middle to form broad plate, acutely angled at apex, with one small tooth in middle; ventral spine short, acute at apex; lamella large; parameres long, overlapping apical lobe, enlarged apically.
Differential diagnosis. Lasinus monticola is close to L. mikado and L. yakushimanus by the presence of nail-shaped protuberance on the antennomeres IX, but it differs from L. yakushimanus by the shape of the genal region of the head and the pronotum, and it differs from L. mikado by the absence of a deep concavity on antennomeres IX. Lasinus monticola can be readily separated from both species also by the shape of aedeagus.
Head elongate, about 1.15 times longer than wide, slightly longer than pronotum; median sulcus absent along whole length of head. Genae simple, lacking protuberances.
Antennae long about 2.10 mm; scapes long, about 4 times longer than pedicels; pedicels shortest, 1.25 times shorter than antennomeres III; antennomeres III, IV, VII and VIII subequal in length, slightly shorter than V and VI ; antennomeres XI 0.71 times longer than wide only slightly enlarged on the apex of antennomeres in male, in female unmodified; X 0.85 times longer than wide; XI 0.66 times longer than wide. Pronotum about as long as wide, wrinkly, gibbose, with prominent lateral swellings before lateral foveae (Fig. 9); lateral and median setose foveae well-defined; median sulcus present only on disc, not originates from median fovea, very short and fine, largely separated from anterior margin of pronotum. Legs long and slender; protrochanters with small apical spine; profemora with small spine in middle; mesotrochanters at apex with small median spine (male) or two (female) spines; mesofemora with small spine at basal third.
First visible abdominal tergite (IV) glabrous, very long, about 3.50 times longer than second (V); basal carinae very short, distance between carinae about 0.5 of maximal tergal width. Aedeagus (Fig. 22) 0.66 mm long; median lobe weakly narrowed apically, with short and very large apical lobe; endophallus with one large, bifid spine and one lamella; lamella large, with dentation on inner left part; parameres short and slender, not overlapping apical lobe.
Differential diagnosis. Lasinus sinicus is close to L. mandarinus by the similar shape of the pronotum with prominent lateral swellings before the lateral foveae. They can be separated from it by the proportion of antennomere X which is almost as long as wide in L. sinicus.
Head elongate, about 1.10 times longer than wide, slightly longer than pronotum; median sulcus visible on rostrum, on vertex reaching level of vertexal foveae. Genae with weak protuberance, covered with erected, dense golden setae.
Antennae about 2.15 mm long (Fig. 13); scapes long, about 3.4 times longer than pedicels; pedicels about 1.18 times shorter than antennomeres III, antennomeres V and VI as long as pedicels; VII 1.25 times shorter than VI; antennomeres VIII about 1.27 times longer and distinctly wider than VII; antennomeres IX about 1.5 times longer than wide, about the same length as terminal antennomeres, in male with deep ventral concavity on apical half terminating with nail-shaped protuberance, in female unmodified; antennomere X quadrate, 1.5 times shorter than IX; terminal antennomeres 1.6 times as long as X and about 1.5 times longer than wide.
Pronotum about as wide as long, wrinkly, evenly rounded before lateral foveae; lateral and median setose foveae well-defined; median sulcus thin.
Legs long and slender; protrochanters with large apical spine; profemora with long spine in middle of its length; mesotrochanters at apex with two minuscule (male) or two strong (female) and one minuscule spine; mesofemora with minuscule spine at basal third.
Abdomen slightly wider than elytra; first visible abdominal tergite (IV) finely punctate, with dense and long golden setae, about 4 times longer than second visible tergite (V); basal carinae very short, distance between carinae 0.53 of maximal tergal width. Aedeagus (Fig. 23) 0.61 mm long; median lobe weakly narrowed apically, with long and relatively narrow apical lobe; endophallus with one bifid spine and two small lamellas; lamellas finely dentate on the apical part; parameres long, overlapping apical lobe, enlarged at apex. Differential diagnosis. Lasinus mikado is close to L. monticola and L. yakushimanus by the presence of a nail-shaped protuberance on antennomeres IX, it differs from both by the presence of a deep concavity on antennomeres IX and by the shape of aedeagus.
Etymology. The name is derived from the Japanese word -"mikado", meaning the Emperor of Japan.
Head elongate, 1.08 times longer than wide and as long as pronotum; median sulcus visible on rostrum, relatively shallow at level of vertexal foveae. Genae with weak protuberance, covered with erected, dense golden setae. Antennae (Fig. 14) about 2.02 mm long; scapes long, about 2.85 times longer than pedicels; pedicels short, 1.42 times shorter than each of antennomeres III-IV; antennomeres V and VI of same length; antennomeres VII 1.22 times longer than wide; VIII longer than wide; XI longer than wide, simple, only slightly oblique on ventral side in male, in female unmodified ; X slightly longer than wide ; XI longer than wide.
Legs long and slender; protrochanters with long apical spine; profemora with short, strong spine in middle; mesotrochanters with one small (male) or two (female) spines; mesofemora with small spine at basal third.
First visible abdominal tergite (IV) very long, about four times longer than second visible tergite (V), with fine punctation in anterior part, disc glabrous, surrounded with short golden pubescence on sides; carinae short, distance between carinae 0.4 of maximal tergal width. Aedeagus (Fig. 24) 0.57 mm long; median lobe weakly narrowed apically, with large and relatively short apical lobe; endophallus with two spines and small lamella; ventral spine very big, forming large plate; dorsal spine big, curved, acute at apex; lamella small, finely dentate in apical part; parameres short and slender, reaching apical lobe, enlarged at apex. Differential diagnosis. Lasinus yamamotoi resembles L. inexpectatus due to the unmodified antennal clubs in both sexes, but it can be distinguished from the latter by the proportion of the antennomeres VII and the shape of the aedeagus.

Lasinus inexpectatus
Head about 1.05 longer than wide, and as long as pronotum; median sulcus very weakly-defined, slightly visible only on rostrum, absent on vertex. Genae with weak protuberance, covered with erected, dense golden setae.
Antennae 2.20-2.24 mm long (Fig. 15); scapes long, about 3.25 times longer than pedicels; pedicels slightly shorter than antennomeres III-VII combined, which are subequal; VIII slightly longer and about 1.30 times wider than VII; antennomeres IX rectangular, simple, in male slightly shorter (0.18 mm) than in the female (0.24 mm); X about as wide as long; terminal antennomeres 1.60 times longer than X. Pronotum 1.05 times longer than wide, wrinkly, evenly rounded before lateral foveae; lateral and median setose foveae well-defined; median sulcus thin, present only on disc.
Legs long and slender; protrochanters with large apical spine; profemora with long spine in middle of its length; mesotrochanters at apex with one minuscule (male) or two strong (female) spines; mesofemora with minuscule spine at basal third.
Abdomen slightly wider than elytra; first visible abdominal tergite (IV) finely punctate with dense and long golden setae on sides, disc glabrous, about 3 times longer than second visible tergite (V); basal carinae very short, almost invisible in males. Aedeagus (Fig. 25) 0.63 mm long; median lobe weakly narrowed apically, with long and narrow apical lobe; endophallus with three spines and small lamella; ventral spine large, forming large plate, acute and curved at apex; dorsal spine large, curved, acute at apex; lateral spine very slender and small, acute at the apex; lamella small, finely dentate on apical part; parameres short, unequal in length, not overlapping apical lobe, enlarged at apex. Differential diagnosis. Lasinus inexpectatus is close to L. sinicus due to the simple antennomeres IX lacking any sexual character. The two species can be separated by the absence of swellings before lateral foveae on the pronotum in L. inexpectatus. From all other Japanese species, L. inexpectatus also differs by the shapes of the aedeagus and the antennae.
Etymology. The name is realated with the "unexpected" discovery of this species. Distribution. Japan (Kyushu). Head elongate, about 1.07-1.11 times longer than wide and about as long as pronotum; median sulcus visible on rostrum and on vertex reaching level of vertexal foveae. Genae with weak protuberance, covered with erected, dense golden setae (Fig. 7).
Antennae about 1.94 mm long (Fig. 16); scapes long, about 3.0 times longer than pedicels; pedicels as long as antennomeres III; antennomeres IV and V slightly longer than wide; antennomeres VI 1.62 times longer than wide; antennomeres VII as long as wide; antennomeres VIII as long as and slightly wider than VII; IX about 1.20 times longer than wide, in male with shallow ventral excavation on apical half terminating with small nail-shaped protuberance, in female unmodified; antennomeres X 1.21 longer than wide; terminal antennomeres about 1.27 times longer than wide.
Legs long and slender; protrochanters with large apical spine; profemora with longer spine in middle of its length; mesotrochanters at apex with two minuscule (male) or two strong and one minuscule (female) spines; mesofemora with minuscule spine at basal third.
Abdomen slightly wider than elytra; first visible abdominal tergite (IV) finely punctate, with dense, very short golden setae; carinae short, distance between carinae 0.49 of maximal tergal width. Aedeagus (Fig. 26) 0.56 mm long; median lobe weakly narrowed apically, with short and large apical lobe; endophallus with two spines; ventral spine large, forming narrow curved plate; dorsal spine slender, evenly curved, acute at apex; parameres long, overlapping apical lobe, enlarged at apex. Differential diagnosis. Lasinus yakushimanus is close to L. okinawanus by sharing the presence of weak lateral swelling on the pronotum, and to L. monticola by the presence of a nail-shaped protuberance on antennomeres IX, it differs from both by the shapes of the antennae and the aedeagus.
Etymology. The name is associated with the name of the locality, Yakushima, where the speciments was found.
Antennae about 1.96 mm long (Fig. 17); scapes about 3.40 times longer than pedicels; pedicels 1.40 times shorter than antennomeres III; III slightly longer than wide; IV as long as III; antennomeres V slightly longer than wide; VI about 1.20 times longer than wide; antennomeres VII 1.2 times longer than wide; VIII 1.16 times longer than wide; IX about 1.10 times longer than wide, in male with well-developed tubercles in apical ventral part, in female unmodified; antennomeres X as wide as long; terminal antennomeres about 1.47 times longer than wide.
Pronotum about as wide as long, wrinkly, with weak lateral swellings before lateral foveae; lateral and median setose foveae well-defined; median sulcus thin and deep.
Legs long and slender; protrochanters with large apical spine; profemora with long spine in middle; mesotrochanters at apex with one (male) or two (female) spines; mesofemora with minuscule spine at basal third.
Abdomen slightly wider than elytra, first visible abdominal tergite (IV) finely punctate with dense and long, golden setae; carinae short, distance between them 0.47 of maximal tergal width. Aedeagus ( Fig. 27) 0.59 mm long; median lobe weakly narrowed apically, with long and narrow apical lobe; endophallus with two spines and one small lamella; ventral spine large, enlarged, forming large plate, acute at left apex; dorsal spine very big, acute at apex; lamella large, finely dentate on apical part; parameres short and slender, reaching apical lobe. Differential diagnosis. Lasinus amamianus and L. saoriae differ from all other species of the genus by the shape of antennae, especially by the presence of tubercles on antennomeres IX. Lasinus amamianus can be readily separated from L. saoriae by the proportion of antennomeres VII and VIII and by the shape of aedeagus.
Etymology. The species name is associated with the name of the locality, Amami-ôshima Island, where most of the specimens were found.