﻿A review of the genus Hesperosoma Scheerpeltz (Coleoptera, Staphylinidae, Staphylininae) of China

﻿Abstract A review of 16 species of Hesperosoma Scheerpeltz from China is presented. Five new species are described: H.(s.str.)chenchangchinisp. nov. from Yunnan, H.(s.str.)languidumsp. nov. from Yunnan, H.(s.str.)motuoensesp. nov. from Xizang, H. (Paramichrotus) parvioculatumsp. nov. from Hubei, Hunan and H.(s.str.)xizangensesp. nov. from Xizang. Two species are new to China: H. (Paramichrotus) brunkei Schillhammer, 2015 from Yunnan and H.(s.str.)kleebergi Schillhammer, 2009 from Xizang. Females of H. (Paramichrotus) alexpuchneri Schillhammer, 2009, H. (Paramichrotus) guizhouense Schillhammer, 2018 and H.(s.str.)flavoterminale Schillhammer, 2004 are described for the first time. Habitus and diagnostic characters of all species are photographed and a key to Chinese species of Hesperosoma is provided.


Introduction
Hesperosoma Scheerpeltz, 1965 is an Asian genus with 29 known species (Schillhammer 2004(Schillhammer , 2015(Schillhammer , 2018 in the subtribe Anisolinina Hayashi, 1993 of the tribe Staphylinini. The species of this genus may be easily distinguished from members of related genera (Philomyceta, Hesperoschema) by segment 2 of maxillary palpi less dis-tinctly or hardly dilated, abdominal tergites III-V with medio-basal depression laterally bordered by more or less distinct oblique ridges (abdominal tergites III-VI with medio-basal depression laterally bordered by more or less distinct oblique ridges in Philomyceta and segment 2 of maxillary palpi comparatively slender in Hesperoschema) (Schillhammer 2004). The genus is currently subdivided into two subgenera, Hesperosoma Scheerpeltz, 1965 andParamichrotus Naomi, 1982. The major differences separating the two subgenera are in the shape of aedeagus and the body colouration: with aedeagus symmetrical and fore body always with a certain amount of reddish colour on the elytra or pronotum in Paramichrotus, while the aedeagus is asymmetrical and fore-body with metallic tint throughout in Hesperosoma (Schillhammer 2015).
Up to now, nine species of the genus have been recorded from China. In this paper, five new species are described and two species are new country records for China. Thus, the total number of Hesperosoma in China is increased to 16. The members of the subgenus Hesperosoma are distributed in mountainous areas of southwest China, while the members of the subgenus Paramichrotus are widely distributed in southern China. (Fig. 1).
The species of the genus Hesperosoma can be usually found in undisturbed forests. Microhabitats include leaf litter, decaying logs and ground-based debris in woodlands with mixed shrub and grassland (Schillhammer, 2004(Schillhammer, , 2015(Schillhammer, , 2018Hu et al. 2020). Based on our collecting experiences, the species of the subgenus Paramichrotus prefer rotten material, especially rotten bamboos, where they hunt for maggots (Figs 6,7). Therefore, an efficient way to collect them is to set rotten bamboo traps (Fig. 2). Species of the Paramichrotus sometimes may also be found sucking sap around tree wounds (Fig. 8). A similar behaviour was previously described by Hu et al. (2020) on rotting stems of Alocasia odora (G. Lodd.) Spach. Species of the subgenus Hesperosoma prefer decaying trees with fungi (Figs 3, 4). Members of both subgenera hide from light inside log or fungi crevices in daylight and they are usually spotted by searching logs in dense forests or at night (Fig. 5).

Materials and methods
The specimens, examined in this paper, were collected by searching logs, sifting rotten bamboo or leaf litter and were euthanised with ethyl acetate. For examination of the genitalia, the last three abdominal segments were detached from the body after softening in hot water. The aedeagus or tergite X, together with other dissected pieces, was mounted in Euparal (Chroma Gesellschaft Schmidt, Koengen, Germany) on plastic slides. Photos of sexual characters were taken with a Canon G9 camera attached to an Olympus SZX 16 stereoscope; habitus photos were taken with a Canon macro photo lens MP-E 65 mm attached to a Canon EOS7D camera and stacked with Zerene Stacker.
The specimens treated in this study are deposited in the Department of Biology, Shanghai Normal University, P. R. China (SHNU) and Naturhistorisches Museum Wien, Austria (NMW). Body measurements are abbreviated as follows: BL body length, measured from the anterior margin of the clypeus to the posterior margin of abdominal tergite X; EL length of elytra, measured from humeral angle; EW width of elytra at the widest point; EYL length of eye; FL fore-body length, measured from the anterior margin of the clypeus to the apex of the elytra (apicolateral angle); HL length of head along the mid-line; HW width of head including eyes; PL length of pronotum along the mid-line; PW width of pronotum at the widest point; TL length of tempora.
Pronotum 1.14-1.20 times as long as wide, widest at level of large lateral seta, narrowed towards base in wide, but shallow concave arc; surface as densely and coarsely punctate as on head, with indistinct, short impunctate mid-line in posterior half; scutellum with dense and pit-like punctation, interstices forming small transverse rugae.
Abdominal tergites III-V with basal transverse depression, punctation of abdominal tergites IV-V moderate and sparse at base, abdominal tergite III impunctate at base; posterior halves of abdominal tergites III-V and entire surface of remaining tergites with very fine and dense punctuation.
Male. Protarsomeres 1-4 moderately dilated, heart-shaped; sternite VII with patch of yellow setae on median portion and posterior margin broadly emarginate at middle; sternite VIII with posterior margin broadly emarginate at middle; aedeagus (Figs 15-17) with median lobe and paramere slightly asymmetrical, paramere ( Fig. 17) shorter than median lobe and slightly bent to left side in ventral view.
Female. Tergite X (Fig. 18) slightly asymmetrical with posterior margin projecting at middle.
Etymology. This species is named in honour of Mr. Chang-Chin Chen who donates lots of staphylinid specimens to the SHNU, including the holotype of the new species.
Distribution. China (Yunnan). Diagnosis. Amongst the species of the nominal subgenus with reddish abdomen, H. malaisei from Myanmar, H. chinense (Shaanxi, Hubei, Sichuan) and H. rufomarginatum from Vietnam, the new species may be easily recognised by four outer segments of antennae creamy white (five outer segments of antennae creamy white in H. chinense and H. malaisei), entirely metallic dark blue to violaceous blue elytra (reddish suture and shoulders of elytra in H. rufomarginatum). Head and pronotum metallic violaceous blue to deep blue, elytra dark metallic violaceous blue, usually a bit more opaque than head and pronotum; abdomen with segments III-VI dark red, segment VII dark red with posterior margin broadly reddishyellow, segments VIII and X entirely reddish-yellow, segment IX reddish-yellow with apical third of latter blackish; antennae black, base and apex of segments 1 and 2 and  base of segment 3 reddish, four outer segments creamy white; mandibles dark reddishbrown; maxillary palpi with segments I-III black, segment IV brown, labial palpi with segments I and II black, segment III brown. Head (Fig. 12) 1.22 times as wide as long, rounded trapezoid, tempora regularly convex, eyes moderately protruding; surface with dense and shallow punctation, mostly contiguous; frons impunctate; with short, weakly delimited impunctate mid-line, extending from impunctate frons to about half of mid-length; antennae with segments 4-8 markedly oblong, segment 9 slightly oblong.

Hesperosoma (s.str.) chinense Hayashi, 2002
Pronotum 1.20 times as long as wide, slender, widest at level of large lateral seta, narrowed towards base in wide, but shallow concave arc; surface as densely and shallowly punctate as on head, with indistinct, short impunctate mid-line in posterior third; scutellum with dense and shallow punctation, interstices forming small transverse rugae.
Abdominal tergites III-V with basal transverse depression, punctation of abdominal tergites III-V feeble at base; posterior halves of abdominal tergites III-V and entire surface of remaining tergites with very fine and dense punctation.
Male. Protarsomeres 1-4 moderately dilated, heart-shaped; sternite VII with patch of long bright yellow setae on median portion; sternite VIII with posterior margin emarginate at middle; aedeagus (Figs 38-40) with median lobe and paramere slightly asymmetrical, paramere (Fig. 40)  Head and pronotum brilliant metallic green to bluish-green, elytra brighter metallic green, bluish-green at shoulders, along sides and at posterolateral angles; abdomen with segments III-V reddish (in one specimen, abdomen with segments III-V reddish, medio-posterior portion darkened on segments IV and V), segments VI-VII dark brown, but segment VII with apical portion broadly yellow, segments VIII-IX entirely pale yellow; antennae with segments 1-6 black, base of segment 2 reddish, segments 7-11 creamy white; mandibles reddish with narrowly darkened medial and lateral margins; palpi dark reddish-brown with paler reddish tips; legs reddish-brown.
Pronotum 1.11-1.18 times as long as wide, widest at about level of large lateral seta, narrowed towards base in distinct concave arc; punctation of surface similar to that of head, with narrow impunctate mid-line; scutellum densely furnished with pitlike punctures, but punctures, although almost contiguous, well isolated. Elytra 0.94-1.00 times as long as wide, surface slightly uneven, with distinct depression between shoulders, scutellum and apical margin of elytra, along suture slightly elevated; punctation dense, but punctures not contiguous, separated by less than a puncture diameter in transverse direction; pubescence yellow, long and dense along suture and posterior elytral margin.
Abdominal tergites III-V with basal transverse depression; punctation of abdominal tergites III-V pit-like at base, gradually becoming finer towards apical margin, pitlike punctures occupying more than basal half on tergite III, about basal half on tergite IV and about basal third on tergite V; abdominal tergites VI-VIII with punctures similar in size, interstices smooth.
Male. Protarsomeres 1-4 moderately dilated, heart-shaped; sternite VII with patch of long yellow setae on median portion, posterior margin broadly emarginate at middle; sternite VIII with posterior margin emarginate at middle; aedeagus (Figs 43-45) with median lobe and paramere slightly asymmetrical, paramere (Fig. 45) shorter than median lobe and medio-apically emarginate. Female. Tergite X (Fig. 46)  Head metallic dark blue to violaceous blue, pronotum and elytra metallic dark blue to violaceous with purplish hue; abdomen with segments III-VI black, segment VII black with posterior margin broadly reddish-yellow, segments VIII and X entirely reddish-yellow, segment IX reddish-yellow with apical half of latter blackish; antennae black, base and apex of segment 1 and 2 reddish, four outer segments creamy white; mandibles black, medial margin and distal portion of mandible dark reddish-brown; maxillary and labial palpi deep black, last segments sometimes slightly paler brownish. Head (Fig. 11) 1.29 times as wide as long, rounded trapezoid, tempora narrowed towards neck in regular arc, eyes moderately protruding; surface with dense and coarse punctation, mostly contiguous; with short, weakly delimited impunctate mid-line, extending from frons to about half of mid-length; antennae with segments 4-8 markedly oblong, segments 9 and 10 about as long as wide.
Pronotum 1.18 times as long as wide, widest at level of large lateral seta, narrowed towards base in wide, but shallow concave arc; surface as densely and coarsely punctate as on head, with indistinct, short impunctate mid-line in posterior third; scutellum with dense and pit-like punctation, interstices forming small transverse rugae.
Abdominal tergites III-V with basal transverse depression, punctation of abdominal tergites III-V large, but feeble at base; posterior halves of abdominal tergites III-V and entire surface of remaining tergites with very fine and dense punctuation.
Male. Protarsomeres 1-4 moderately dilated, heart-shaped; sternite VII with patch of long yellow setae on median portion and posterior margin broadly emarginate at middle; sternite VIII with posterior margin emarginate at middle; aedeagus (Figs 55-57) very similar to that of H. puetzi and H. xizangense sp. nov., but markedly larger, median lobe and paramere slightly asymmetrical, paramere (Fig. 57) shorter than median lobe and slightly bent to left side in ventral view.
Female. Unknown. Etymology. The species is named after the type locality Distribution. China (Xizang). Diagnosis. The new species is very similar externally to H. languidum sp. nov. (Yunnan) and H. puetzi (Sichuan), but can be recognised by the emarginated anterior margin of frons (Figs 8-9), as well as by the different shape of the aedeagus, especially the paramere, which is broad and truncate apically. Additionally, the head is wider, 1.29 times as wide as long (1.14-1. 16     Diagnosis. The collecting locality of the male specimen is about 760 km away from the holotype locality in north-eastern Laos and about 210 km away from the paratype locality in Myanmar. The specimen fits the original description in all characters, but the medio-apical margin of the paramere looks slightly different as well as the apex of the median lobe in lateral view. The ventral view of the median lobe as depicted here is more representative of the species, as it is matching that of the other specimens of the type series. The shape of the paramere is here considered as within the variability range of this widespread species. The females correspond with the original description in all characters. collection data as for the preceding; but 11 May 2019 • 1♀; Longquan City, Fengyangshan N. R., Lu'aocun Village;27°55'19.66"N, 119°11'38.86"E;alt. 1076     of segment 3 reddish, segments 8-11 creamy white; mandibles dark reddish-brown; maxillary palpi reddish, labial palpi with segments 1 and 3 reddish, segment 2 black brown; legs reddish-yellow, femora reddish-brown.

Hesperosoma
Head 1.48-1.63 times as long as wide, rounded trapezoid, tempora narrowed behind eyes; dorsal surface coarsely and very densely punctate, punctures contiguous, including clypeus; antennae rather short, antennae with segments 4-7 weakly oblong, segments 8 and 10 about as long as wide.
Pronotum 1.08-1.13 times as long as wide, widest at about level of large anterolateral seta, narrowed towards base in weak concave arc, surface with dense and coarse punctation similar to that on head, with narrow impunctate mid-line, ground pubescence slightly more obvious than that on head; scutellum uniformly, densely punctate, space between punctures with very fine wavy microsculpture.
Elytra as long as wide, along sides distinctly longer than pronotum, with slightly uneven surface, densely punctate and pubescent, with distinct depression between shoulders, scutellum and apical margin of elytra; pubescence yellow, long and dense along suture and posterior elytral margin.
Abdominal tergites III-V with transverse basal depression and pair of short oblique basal carinae, punctation very sparse and rather coarse basally and laterally, gradually becoming finer towards apical margin, tergites VI-VIII entirely with fine and uniform punctation and pubescence, colour of pubescence corresponding with colour of integument underneath; legs long and slender.
Male. Protarsomeres 1-4 moderately dilated, heart-shaped; sternite VII with the usual setose groove and patch of long yellow setae on median portion, posterior margin broadly emarginate at middle; sternite VIII with posterior margin emarginate at middle; aedeagus (Figs 92-94) with apex of median lobe broad, anterior margin with gibbosities at middle (ventral view); paramere ( Fig. 94) with narrow apical portion, shorter than median lobe.
Female. Tergite X (Fig. 95) slightly asymmetrical with short apex. Etymology. The specific epithet refers to the small eyes of the new species. Distribution. China (Hubei and Hunan). Diagnosis. Externally, H. parvioculatum sp. nov. is virtually identical to H. nigricolle from Myanmar, but differs mainly, aside from the distribution, by the shape of the aedeagus: paramere with narrow apical portion (paramere with broad apical portion, distinctly bilobed in H. nigricolle); the wider head with HW/HL about 1.48-1.63 (1.35 in H. nigricolle); posterior angles of the head being rounded (slightly prominent in H. nigricolle); legs reddish-yellow, femora reddish-brown (legs reddish to yellowish-red, distal halves of femora black in H. nigricolle). In appearance, it is also similar to H.