Platydracus gracilis, Zhou & Zhao & Tang, 2024

Zhou, Cheng-Lin, Zhao, Qing-Hao & Tang, Liang, 2024, A taxonomic study of the Platydracus brachycerus group with descriptions of three new species from China (Coleoptera: Staphylinidae, Staphylininae), Zootaxa 5399 (5), pp. 505-516 : 509-514

Platydracus gracilis sp. n.

( Figs. 7, 8 , 19, 20 )

Type material. Holotype. China: Guangxi: ♁, glued on a card with labels as follows: “China: Guangxi Province, Huanjiang county, Jiuwan Mt, Yangmeiao , FIT, 25°12′N, 108°40′E, alt. 1250m, 25.IV.2021, Tang, Peng & Cai leg.” “Holotype / Platydracus gracilis / Zhou, Zhao & Tang” [red handwritten label] ( SHNU) . Paratypes. Guangxi: 1♀, Xing′an County, Maoershan , beech forest mixed leaf litter, humus sifted, 25°52′N, 110°24′E, alt. 1940m, 29.VI.2014, Peng, Song, Yu & Yan leg. ( SHNU) .

Description. Measurements of male: BL: 13.3 mm, FL: 6.4 mm. HL: 1.60 mm, HW: 1.94 mm, EYL: 0.51 mm, TL: 0.68 mm, PL: 2.14 mm, PW: 1.95 mm, EL: 2.60 mm, EW: 2.39 mm. HW/HL: 1.21, TL/EYL: 1.33, PL/PW: 1.10, EL/EW: 1.09.

Measurements of female: BL: 12.0 mm, FL: 5.6 mm. HL: 1.33 mm, HW: 1.67 mm, EYL: 0.50 mm, TL: 0.56 mm, PL: 1.89 mm, PW: 1.64 mm, EL: 2.34 mm, EW: 2.28 mm. HW/HL: 1.26, TL/EYL: 1.12, PL/PW: 1.15, EL/ EW: 1.03.

Body blackish, apical margin of abdominal segment VII and apical third of abdominal segment VIII reddish brown, maxillary palpi and labial palpi reddish brown with apical margin of each segment lighter.

Head 1.21–1.26 times as wide as long, rounded at posterior angles; eyes moderately large, moderately convex; surface with moderately dense and coarse punctation, intermixed with very fine punctures, anterior portion of frons impunctate, pubescence brownish; pubescence behind anterior margin and eyes slightly paler; antennae with basal 3 segments distinctly longer than wide, segments 4 to 10 distinctly transverse, gradually incrassate, segments 5 to 11 covered with dense pubescence; maxillary palpi stout, their last segment narrowly subtruncate apically; mandible robust, inner edge of left mandible with two teeth on upper plane and a midle tooth on lower plane, inner edge of right mandible with two teeth.

Pronotum 1.10–1.15 times as long as wide, lateral sides curved inward in apical half; disc without impunctate midline, punctation sparser and finer than that of head, intermixed with fine punctures, pubescence brownish; scutellum with dense rugulose punctation and brownish yellow pubescence.

Elytra 1.03–1.09 times as long as wide, punctation dense and fine, pubescence brownish except for that behind humeri, along suture and posterior elytral margin slightly paler.

Abdominal tergites III–VI with basal transverse depression, punctation similar in size, pubescence brownish to silver.

Male. Abdominal sternite VII with large median depression bearing long brownish setae; sternite VIII with posterior margin emargination in the middle; aedeagus ( Figs. 19, 20 ) symmetrical, median lobe elongate with lateral sides subparallel forming a broad round apex in ventral view; paramere subtriangular, slightly curved ventrad in lateral view, apex with a single seta.

Distribution. The species is known from two montane localities (1250 m and 1940 m) in Guangxi province, south-east China.

Diagnosis. The new species is similar to P. juang and P. brachycerus in appearance, but it can be distinguished from these species by the shorter head, antennomeres 5 to 11 covered with dense pubescence (4 to 11 covered with dense pubescence in P. juang and P. brachycerus ), pronotum with lateral sides curved inward in apical half, and apex of aedeagal paramere with a single seta.

Etymology. The specific epithet refers to the slender body shape of the new species.

Figures

FIGURES 7–12. Habitus. Habitus. 7, 8—Platydracus gracilis; 9, 10—P. paragracilis; 11, 12—P. donnyi. Scale bars: 2 mm.

FIGURES 19–24. Aedeagal characters. 19, 20—Platydracus gracilis; 21, 22—P. paragracilis; 23, 24—P. donnyi; 19, 21, 23— aedeagus in ventral view; 20, 22, 24—aedeagus in lateral view. Scale bars: 0.5 mm.