Batriscenellus xijiaogongyuan, new species

(Figs 1 A, 3A, 3D–G, 4A–B)

Type material. Holotype: CHINA: ♂, labeled ‘ China: Shanghai, Changning District (长宁区), Shanghai Zoo (上 海动 物园), 31°11'54"N, 121°21'19"E, alt. 10 m, artificial mixed forest, sifted, 26.v.2016, Hu, Peng, Tu, Wang, Zhou leg.’ (SNUC).

Diagnosis of male. Dorsal surface of head and pronotum coarsely punctate; legs simple, lacking modification; abdominal tergite IV with a large cavity at the basal half of the tergite, with a small projection and pair of setose tufts inside the cavity; aedeagus with a long, curved, and apically pointed dorsal lobe, and with shorter, apically pointed ventral lobe narrowing from base toward apex.

Description. Male (Fig. 1 A). Body reddish brown, length 2.02 mm. Head rectangular, slightly wider than long, HL 0.40 mm, HW 0.47 mm, dorsal surface coarsely punctate (Fig. 3 A); antennal tubercles moderately raised; vertexal foveae nude, located at point level with middle of eyes; antenna 11-segmented, length 0.18 mm, clubs formed by apical three enlarged antennomeres; ocular-mandibular carinae present; each eye composed of about 35 facets. Pronotum about as long as wide, PL 0.46 mm, PW 0.47 mm, disc coarsely punctate (Fig. 3 A). Elytra wider than long, EL 0.65 mm, EW 0.74 mm, narrowed at base, shallow discal striae extending posteriorly to 3/4 of elytral length. Legs slender, simple, lacking modification. Abdomen wider than long, AL 0.51 mm, AW 0.65 mm; tergite IV (first visible tergite; Fig. 3 D) longer than V–VII combined, with large cavity at basal half of tergite, with one small projection and pair of setose tufts inside cavity, setiferous patches present at sides of cavity, thick discal carinae forming sides of cavity; tergites IV and V with bunch of thick setae at middle of posterior margin. Aedeagus (Fig. 3 E–G) strongly asymmetric, length 0.28 mm, dorsal lobe strongly curved leftwards in ventral view, with pointed and strongly bent apex, ventral lobe shorter and narrower, broadest at base, evenly narrowing from base toward apex.

Female. Unknown.

Comparative notes. The presence of a mediobasal cavity on male tergite IV places B. xijiaogongyuan near B. chinensis Yin & Li (in Yin et al. 2011: 42) and B. pulcher Yin & Li (in Yin et al. 2011: 45) of the B. auritus group, both known from Zhejiang, eastern China. Also, the aedeagi of these three species are more or less similar in form (Fig. 3 F, Yin et al. 2011: figs 23, 27). However, the new species has the male abdominal tergite V with a tuft of thick setae on the posteromedian margin, a character unknown in any other member of the B. auritus group and thus can be used to readily separate B. xijiaogongyuan from both B. chinensis and B. pulcher. The unique combination of the diagnostic features (see Diagnosis above) of the new species also leads to a ready separation from all other known congeners.

Habitat. The single male was collected from sifted samples in an artificial mixed forest at Shanghai Zoo (Fig. 4 A–B).

Distribution. Eastern China: Shanghai.

Etymology. ‘Xijiaogongyuan’ is the standard Pīnyīn of ‘ OiḚẌDz ’ (English: Xijiao Park), which was an old name of the Shanghai Zoo that was used for many years.