Homalota nanjingensis Cao, Ji & Liu, 2018

Cao, Dandan, Wei, Jianrong, Liu, Shuwen, Zhao, Zhengping, Wang, Liping & Ji, Baozhong, 2018, A new species of Homalota Mannerheim, 1830 (Coleoptera: Staphylinidae: Aleocharinae) from Nanjing, China, Zootaxa 4444 (3), pp. 327-332 : 328-330

Homalota nanjingensis Cao, Ji & Liu , sp. nov.

Type locality: China, Jangsu rpovince, Nanjing Zijin Mountain.

Type materials: HOLOTYPE ♂: China, Jiangsu province, Nanjing Zijin Mountain National Forest Park, 15 August 2013, coll. S. W. Liu & D . D. Cao. PARATYPES: 3♀, China, Jiangsu province, Nanjing , 8 July 2013, coll. Z. P. Zhao & D . D. Cao. 4♂, China, Jiangsu province, Nanjing , 12 September 2013, coll. L. P. Wang & D. D. Cao . All type specimens are deposited in the Insect Museum of Hebei University , Baoding, China .

Description: Body length about 1.5–2.0 mm. Body strongly flattened dorsoventrally, parallel-sided; slightly pubescent; yellowish brown, head, elytra, and abdominal tergite VI dark brown ( Fig. 1 ).

Head: Subquadrate (HL = 0.29± 0.02 mm; HW = 0.27± 0.01 mm; HW/HL = 1.11); eyes moderate in siZe, and slightly protruding outwards ( Fig. 2 ), between ommatidia with sparse setae; antenna with 11 segments, 1–3 elongate, 4–10 transverse, moniliform ( Fig. 3 ).

Mouthparts: Labrum transverse, with 8 pairs of macrosetae symmetrically arranged on the two sides of longitudinal midline.α-sensillum with a setose process, c- and γ-minute and conical, ε with a short setose process, distinctly shorter than α ( Fig. 4 ); the molar region of the mandibles dorsal surface with small denticles, right mandible with small median tooth, prostheca well developed ( Fig.5 ); labial palpi with sparse setae, labium with ligula moderate in length and bifid at half, a little shorter than labial palpomere 1, labial palpomere 1 longer than 2, two medial setae present on prementum, contiguous, side by side, median field of prementum narrow and with pseudopores, mentum slightly marginated in anterior margin ( Fig. 6 ); maXillary palpomere 2 and 3 dilated distally, 4 without small spines at apeX ( Fig. 7-8 ).

Thorax: Pronotum transverse, about 1.29 times wider than long (PW = 0.35± 0.01 mm; PL = 0.27± 0.01 mm; PW/PL = 1.29), posterior margin straight. Elytra slightly wider than pronotum, postero-laterally slightly sinuate. Elytra ( Fig. 10 ) longer than wide (EL = 0.34± 0.02 mm; EW = 0.18± 0.03 mm; EL/EW = 1.91), slightly longer than pronotum (EL/PL = 1.35), hind wings developed, 1-1.5 times than body length. Scutellum postero-medially round. MesocoXae narrowly separated ( Fig. 9 ). Tarsomere 1 as long as 2 in front and middle leg, but longer than 2 in hind legs. Empodial setae present.

Abdomen: Tergites III-?transversely impressed, with clear basal transverse lines; behind them uniformly covered with dense setae.

Female: Posterior margin of female tergite VIII slightly sunk in middle part ( Fig. 11 ); sternite? ( Fig. 12 ) broadly rounded apically. Spermatheca simple and elongate, spermathecal tube slightly curved ( Fig. 13 ).

Male: Posterior margin of male tergite VIII with twao long and acute lateral processes, median area with 4 short and broad processes ( Fig. 14 ); sternite VIII narrowly protruding medially ( Fig. 15 ); aedeagus ( Fig. 16 ) median lobe elongate, bulbous at base, apical process slightly longer than basal bulb ( Fig. 17 ), flagellum well sclerotiZed and short ( Fig. 19 ); the apical lobe of parameres long and nearly fusiform, the middle part dilated ( Fig. 18 ), with two setae per paramere ( Fig. 20 ), and approXimately equal in length.

Habitat and distribution: The specimens were collected in Nanjing Zijin Mountain National Forest Park (Nanjing, China). We found this new species under bark of dead pine trees ( P. massoniana ) that had been killed by nematode B. xylophilus , but we did not find this new species beneath the bark of completely rotten timber. Larvae of H. nanjingensis usually occurred between May and August. In contrast, based on three years of the investigation (2011-2013), adults were found throughout the year, indicating that H. nanjingensis may overwinter as adults.

With the secondary invasion of other insects (e.g. Scolytidae and Cerambycidae ) and microorganisms, the number of staphylinid species increased correspondingly. There was a spatial-temporal niche overlap between Staphylinidae ( H. nanjingensis was the dominant species) and wood borer pests ( Cao et al. 2013b), but whether H. nanjingensis interacts with these wood borers remains unknown. In addition, feeding habits of Aleocharinae beetles are compleXed ( Cao et al. 2013a), research on biology and behavior of H. nanjingensis will be continued.

Etymology: In our study, all samples of this species were collected from the Zijin Mountain National Forest Park, in the east of Nanjing City. The specific name is derived from the name of the type locality, Nanjing.

Comparative remarks: Kim and Ahn (2014) revised the Korean species of Homalota , and provided detailed descriptions of five species and a key. Homalota nanjingensis can be distinguished from all species known in China by the following combination of characters: body strongly flattened dorsoventrally, parallel-sided, slightly pubescent; head slightly narrower than pronotum, posterior margin of pronotum relatively straight; male tergite? with two elongate lateral teeth, and with two setae per paramere. The key of species recorded in China was enclosed (AppendiX 1).

Figures

FIGURES 1–3. Homalota nanjingensis Cao, Ji, Liu, sp. nov.: 1 adult in dorsal view (scale bar = 0.5 mm); 2 head and pronotum, in dorsal view (scale bar = 0.1 mm); 3 antenna (scale bar = 0.1 mm).

FIGURES 4–9. Homalota nanjingensis Cao, Ji, Liu, sp. nov. 4 labrum, ventral aspect (scale bar = 0.02 mm); 5 right mandibles, ventral view (scale bar = 0.03 mm); 6 labium, ventral aspect (scale bar = 0.02 mm); 7 maxilla, ventral aspect (scale bar = 0.05 mm); 8 maxilla and labium (scale bar = 0.05 mm); 9 mesoventrite, ventral aspect (scale bar = 0.1 mm).

FIGURES 10–18. Homalota nanjingensis Cao, Ji & Liu, sp. nov. 10 elytrum in dorsal view (scale bar = 0.1 mm); 11 female tergite VIII (scale bar=0.1 mm); 12 female sternite VIII (scale bar=0.1 mm); 13 spermatheca (scale bar = 0.1 mm); 14 male tergite VIII (scale bar=0.1 mm); 15 male sternite VIII (scale bar=0.1 mm); 16 aedeagus, dorsal view (scale bar = 0.1 mm); 17 median lobe, lateral aspect (scale bar = 0.1 mm); 18 paramere, lateral aspect (scale bar = 0.1 mm).

FIGURES 19–20. Homalota nanjingensis Cao, Ji, Liu, sp. nov. 19 median lobe, ventral view (scale bar = 0.08 mm); 20 paramere, lateral aspect (scale bar = 0.08 mm).