Eight new species of Batrisodes Reitter from China (Coleoptera, Staphylinidae, Pselaphinae)

Abstract Eight new species of the genus Batrisodes Reitter are described from continental China, seven of which were found in association with ants: B. abdominalis sp. n. and B. tianmuensis sp. n. with an Ectomomyrmex ant from Zhejiang; B. grossus sp. n. with an Odontomachus ant from Guangxi; B. simianshanus sp. n. with an Aphaenogaster ant from Chongqing; B. qiului sp. n. with a Pheidole ant, B. xuhaoi sp. n. with a Lasius ant, and B. zhouchaoi sp. n. with Lasius and Nylanderia ants from Sichuan. Batrisodes zethus sp. n. was collected from a leaf litter sample.


Introduction
Eleven species of the genus Batrisodes Reitter are currently known to occur in China, scattered in Zhejiang, Hunan, Sichuan, Yunnan, Xizang (Tibet), Ningxia, and Taiwan (Besuchet 1981;Nomura 2007;Yin and Li 2013;Yin et al. 2011Yin et al. , 2015Jiang and Yin 2016). This number is apparently at a low level in contrast to the 150 described species in the Holarctic region (Chandler 1997;Schülke and Smetana 2015).
Here, another eight new species are added to the Chinese fauna based on newly acquired material, seven of them were collected from ant colonies. This further demonstrates the high morphological disparity among members of Batrisodes, which, however, makes it more difficult to determine a synapomorphy for the genus.

Materials and methods
All type material is housed in the Insect Collection of Shanghai Normal University, Shanghai, China (SNUC).
The collecting data of the material are quoted verbatim. The Chinese translation of each locality below provincial level is included in parentheses at the first appearance in the text. Each type specimen bears the following label: 'HOLOTYPE (red) (or PARATYPE (yellow)), ♂ (or ♀), Batrisodes + specific name sp. n., det. Jiang and Yin 2017, SNUC'. Dissected parts of dead beetles were preserved in Euparal on plastic slides that were placed on the same pin with the specimen. Habitus images were taken using a Canon 7D camera in conjunction with a Canon MP-E 65 mm f/2.8 1-5X Macro Lens, and a Canon MT-24EX Macro Twin Lite Flash was used as light source. Images of the morphological details were made using a Canon G9 camera mounted on an Olympus CX31 microscope under reflected or transmitted light. Zerene Stacker (version 1.04) was used for image stacking. All images were modified and grouped into plates in Adobe Photoshop CS5 Extended.

The following abbreviations are applied AL
length of the dorsally visible part of the abdomen (posterior to elytra) along the midline; AnL length of the antenna; AW maximum width of the abdomen; EL length of the elytra along the suture; EW maximum width of the elytra; HL length of the head from the anterior clypeal margin to the occipital constriction; HW width of the head across eyes; PL length of the pronotum along the midline; PW maximum width of the pronotum.
Length of the body is a sum of HL + PL + EL + AL.

Diagnosis of male.
The new species can be separated from other Chinese Batrisodes species by the following combination of characters: all antennomeres longer than wide; antennomeres X and XI each with a small denticle on the ventral side; mesofemur with a long protuberance near base, sternite V with a small spine at middle, and the slender, asymmetrical aedeagus with an elongate dorsal lobe.
Description. Male. (Fig. 1A), Body reddish brown, BL 2.62 mm. Head slightly wider than long, HL 0.51 mm, HW 0.57 mm, rectangular and covered with short hair, with large vertexal foveae, antennal tubercles prominent; area between moderately raised antennal tubercles concave and impunctate; clypeus slightly punctate, with round anterior margin; lateral longitudinal carinae slight, extending from level of eyes to head base, lacking median vertexal carina. Each eye composed of about 75 facets; Antennomeres II-XI longer than wide, IX-X (Fig. 1B) slightly enlarged, X with small denticle near basal 1/3; XI largest, nearly 2.5 times as long as X, with small denticle near base. Pronotum longer than wide, PL 0.63 mm, PW 0.55 mm, disc slightly convex, with small median antebasal foveae, median and lateral longitudinal sulci distinct; lateral antebasal fovea large and distinct; outer and inner basolateral foveae small but distinct. Elytra wider than long, without punctation and covered with sparse short hair, EL 0.89 mm, EW 0.97 mm, each elytron with three distinct basal foveae, discal striae shallow and unobvious. Mesofemora (Fig. 1C) with long distinct ventral spine near 1/3; mesotibiae ( Fig. 1D) with short obtuse apical spine. Abdomen much wider than long, AL 0.59 mm, AW 0.81 mm; tergite IV longest, more than twice longer than next, with obvious oblique marginal carinae; sternite V (

Diagnosis of male.
The new species can be separated from other Chinese Batrisodes species by the following combination of characters: head dorsum, pronotum, and elytra roughly punctate, antennomeres III-V wider than VI-X, mesotrochanter, mesofemur, and mesotibia spinose, and slightly asymmetrical aedeagus expanded at the apex.
Description. Male. (Fig. 2A), Body reddish brown, BL 2.58 mm. Head approximately as long as wide, near trapezoidal, rough and covered with short hair, HL 0.46 mm, HW 0.50 mm, with large vertexal foveae, antennal tubercles prominent; area between moderately raised antennal tubercles concave; clypeus punctate, with round anterior margin; lateral longitudinal carinae slight, extending from level of eyes to head base, lacking median vertexal carina. Each eye composed of about 50 facets. Antennomeres II-X ( Fig. 3A) moniliform, III-V slightly expanded, XI largest, nearly 2.5 times as long as X. Punctate pronotum slightly wider than long, PL 0.52 mm, PW 0.59 mm, disc slightly convex; with small median antebasal foveae, median and lateral longitudinal sulci distinct; lateral antebasal fovea large and distinct; outer and inner basolateral foveae small but distinct. Elytra as wide as long, with large uniform punctation and covered with long moderate-length hair, EL 0.87 mm, EW 0.87 mm; each elytron with three small but distinct basal foveae, discal striae shallow and unobvious. Biology. All adults were collected from an Odontomachus colony in a tree hole (Fig. 12).
Etymology. The specific epithet refers to the roughly punctate body surface of the new species.

Diagnosis of male.
The new species can be easily separated from other Batrisodes species in China by the following combination of characters: moniliform antennomeres, antennomeres XI with a large projection at the base, mesotrochanter with an abrupt projection at the ventral margin, mesofemur with a small spine at middle, and simple, slender aedeagus distinctly expanded at the apex.
Description. Male. (Fig. 4A), Body reddish brown, BL 3.05 mm. Head slight wider than long, near rectangular, rough and covered with short hair, HL 0.60 mm, HW 0.66 mm, with small but obvious vertexal foveae, antennal tubercles prominent; area between moderately raised antennal tubercles concave; clypeus slightly punctate, with round anterior margin; lateral longitudinal carinae unobvious, lacking median vertexal carina. Each eye composed of about 60 facets. Antennomeres II-XI moniliform, XI (Fig. 4B) largest, with distinct, apically-truncate basal denticle. Pronotum nearly as long as wide, PL 0.65 mm, PW 0.64 mm, disc slightly convex; with distinct median antebasal foveae, lateral longitudinal sulci present; lateral antebasal fovea distinct; outer and inner basolateral foveae small and not distinct. Elytra wider than long, EL 0.93 mm, EW 1.07 mm; each elytron with three small but distinct basal foveae, discal striae shallow and short. Mesotrochanter ( Diagnosis of male. Batrisodes simianshanus can be separated from all other Chinese congeners by the following combination of characters: ocular canthi present, antennomere XI with a small, acute denticle at mesal margin, pronotum lacking outer and inner basolateral foveae, median antebasal foveae small, mesofemur with a distinct ventral protuberance near base, mesotibiae with small apical spine, and symmetrical, robust aedeagus with the endophallus bearing a pair of elongate lateral sclerites. Description. Male. (Fig. 5A), Body reddish brown, BL 3.18-3.20 mm. Head wider than long, near rectangular, rough and covered with short hair HL 0.62-0.63 mm, HW 0.68 mm, with large vertexal foveae, antennal tubercles prominent; area between obviously raised antennal tubercles concave and without hair; clypeus slightly punctate, with round anterior margin; lateral longitudinal carinae slight, extending from level of eyes to head base. Each eye composed of about 60 facets and with one short ocular spine. Antennomeres II-X moniliform, IX-XI (Fig. 6A) slightly expanded, XI large and longest, with small denticle near base. Pronotum nearly as long as wide, PL 0.69-0.70 mm, PW 0.65-0.68 mm, disc slightly convex; with much small media antebasal foveae, median and lateral longitudinal sulci shallow and unclear; lateral antebasal fovea large and distinct, without outer and inner basolateral foveae. Elytra slight wider than long, EL 0.99-1.01 mm, EW 1.14-1.16 mm; each elytron with three small but distinct basal foveae, discal striae shallow and short. Profemora (Fig. 6B) expanded at middle, mesofemora (Fig. 6C) with thin but distinct ventral protuberance near base and expanded at middle; mesotibiae ( Fig. 6D) with small and indistinct triangular apical spine. Abdomen wider than long, AL 0.85-0.89 mm, AW 1.04-1.09 mm; tergite IV longest, twice as long as next, with shallow but distinct oblique marginal carinae. Aedeagus (Fig. 6E-F) symmetrical and robust, median lobe simple, with pair of elongate lateral sclerites, length of aedeagus 0.44 mm.
Female (Fig. 5B). Similar to male, antennomere IX-XI less expanded, XI lacking denticle; each eye composed of about 50 facets; legs simple; tergite VIII (  Biology. All adults were collected from ant colonies nested on the ground under stones (Fig 13).
Etymology. The specific epithet refers to the type locality of the new species, the Simianshan Nature Reserve. Diagnosis of male. Batrisodes tianmuensis can be separated from all other Chinese congeners by the following combination of characters: antennomeres XI strongly concave at the ventral margin and with an acute basal projection, smooth pronotum lacking median antebasal foveae and inner and outer basolateral foveae, mesofemur with a small ventral spine at middle, mesotibia with a blunt apical protuberance, and aedeagus with an elongate, broad dorsal lobe suddenly pointed at the apex.

Batrisodes tianmuensis
Description. Male. (Fig. 7A), Body reddish brown, BL 2.52 mm. Head wider than long, rectangular and covered with sparse short hair, HL 0.51 mm, HW 0.57 mm, with small vertexal foveae; antennal tubercles prominent; area between moderately raised antennal tubercles concave and impunctate; clypeus slightly punctate, with round anterior margin; lateral longitudinal carinae slight, extending from level of eyes to head base, lacking median vertexal carina. Each eye composed of about 55 facets. Antennomeres II-X moniliform, XI (Fig. 7B) largest, approximately 3 times as long as X, strongly concave at mesal surface, with acute denticle near base. Pronotum slightly longer than wide, PL 0.55 mm, PW 0.52 mm, smooth with sparse short hair; disc slightly convex, without median antebasal foveae and median longitudinal sulci; lateral longitudinal sulci shallow, lateral antebasal fovea small and indistinct; lacking outer and inner basolateral foveae. Elytra wider than long, smooth and covered with sparse short hair, EL 0.87 mm, EW 0.99 mm; each elytron with three small basal foveae, discal striae shallow and indistinct. Mesofemora (Fig. 7C) with small thin ventral spine near middle; mesotibiae ( Fig. 7D) with small triangular apical spine. Abdomen much wider than long, AL 0.62 mm, AW 0.95 mm; tergite IV longest, nearly 2.5 times as long as next, with shallow oblique marginal carinae. Aedeagus (Fig. 7E-G)   Diagnosis of male. Batrisodes xuhaoi can be separated from all other Chinese congeners by the following combination of characters: stout general habitus, moniliform antennomeres, antennomere XI with a thick projection at base, profemur strongly expanded near middle, mesotrochanter expanded at ventral margin, mesofemur with a small ventral spine at middle, mesotibia with acute spines at middle and apex, and asymmetrical, elongate aedeagus broadened at the apex.
Etymology. The specific epithet is dedicated to Hao Xu, co-collector of the type series. Batrisodes zethus can be separated from all other Chinese congeners by the following combination of characters: habitus stout, antennomere IX strongly protruding laterally, X oblique, XI with a setose longitudinal projection at the lateral surface, mesofemur with a distinct ventral projection at basal 1/3, mesotibia with small tubercles at middle and apex, aedeagus elongate, with numerous spine-like structures at middle of the ventral lobe.

Batrisodes zethus
Description. Male. (Fig. 10A), Body reddish brown, BL 2.83 mm. Head wider than long, sub-triangular, roughly punctate and with short setae, HL 0.60 mm, HW 0.66 mm, with large vertexal foveae, antennal tubercles prominent, area between tubercles regularly depressed; clypeus finely punctate, with round anterior margin; lacking lateral longitudinal carinae and median vertexal carina. Each eye composed of about 60 facets. Antennomeres II-VIII moniliform, IX (Fig. 10B) strongly protruding at lateral margins and with long hair at apex, X oblique, XI with a distinct longitudinal projection near middle. Pronotum slightly wider than long, PL 0.58 mm, PW 0.62 mm, covered with fine, short hair, disc slightly convex; with small but , distinct mediobasal impression, lateral longitudinal sulci present; lateral antebasal fovea large and distinct; outer and inner basolateral foveae small. Elytra wider than long, uniformly punctate; EL 0.87 mm, EW 1.04 mm; each elytron with three large basal foveae, discal striae shallow, extending to half elytral length. Mesofemora (Fig. 10C) with thick, long projection at basal 1/3; mesotibiae ( Fig. 10D) with small, blunt projection at middle and apex; Abdomen wider than long, AL 0.78 mm, AW 0.97 mm; tergite IV (first visible tergite) longest, nearly 1.5 times as long as next, with oblique marginal carinae; tergite V-VI each with oblique marginal carinae. Aedeagus (Fig. 10E-G)  Diagnosis. Batrisodes zhouchaoi can be readily separated from all other Chinese congeners by the following combination of characters: antennomere X strongly transverse, with a small denticle at mesal margin, XI with a small denticle base; pronotum distinctly winder than long; mesotrochanter with a blunt ventral projection, mesofem-  ora with a long ventral protuberance at middle, mesotrochanter protuberant ventrally, metafemora expanded along the ventral margin; aedeagus strongly asymmetrical, with elongate, twisted ventral and dorsal lobes.
Female. Unknown. Distribution. Southwestern China: Sichuan. Host ant. Lasius sp. and Nylanderia sp. Biology. All adults were collected from ant colonies nesting under stone or bark. Etymology. The new species is named after Chao Zhou, who collected this new species and sent us the material as a gift.