Triomicrus contus Shen and Yin

Shen, Jia-Wei, Yin, Zi-Wei & Li, Li-Zhen, 2015, Triomicrus Sharp of Eastern China (Coleoptera: Staphylinidae: Pselaphinae), Zootaxa 4007 (4), pp. 509-528 : 515-516

Triomicrus contus Shen and Yin , new species

( Fig. 5 )

Type material (5 ♂♂, 9 ♀♀). Holotype: China: ♂, labeled ‘ China: C. Zhejiang, Zhuji, Mt. W. Majian Town (马 剑镇), 29°43’23’’N, 119°59’08’’E, leaf litter, sifted, 200 m, 15.vi.2012, T.-X. Zhao leg.’ ( SNUC). Paratypes: China: 1 ♀, same data as holotype ( SNUC); 1 ♀, labeled ‘ China: C. Zhejiang, Zhuji, Mt. W. Majian Town, 29°43’16’’N, 119°58’51’’E, leaf litter, sifted, 300 m, 30.vi.2012, T.-X. Zhao leg.’ ( SNUC); 1 ♂, labeled ‘ China: W. Jiangxi Province, Yichun City, Mingyue Shan (明月山), 27°35’13’’N, 114°16’53’’E, mixed forest, leaf litter, wood, sifted & beating, ca. 1600 m, 22.x.2013, Peng, Shen & Yan leg.’ ( SNUC); 3 ♂♂, 7 ♀♀, also from Mingyue Shan, ‘ 27°35’44’’N, 114°16’26’’E, mixed forest, leaf litter, wood, sifted & beating, ca. 1140 m, 23.x.2013, Peng, Shen & Yan leg.’ ( SNUC).

Diagnosis. Antennomere XI with relatively deep impression surrounding slightly prominent, disc-like protuberance near base. Head lacking median vertexal carina. Pronotum finely punctate. Elytral subhumeral sulci absent. Profemora simple, protrochanters and protibiae lacking spur or spine, mesotibiae lacking denticle. Apical lamina of abdominal sternite VII broadest near the middle and arcuate toward apex. Aedeagus with right paramere strongly curved mesally, internal sac bearing several sclerotized spines and several densely hairy sclerites.

Description. Male ( Fig. 5 A). Length 2.13–2.20 mm. Head longer than wide, HL 0.42–0.46 mm, HW 0.41– 0.43 mm, lacking median vertexal carina; lateral portions of frons finely punctate; each eye composed of about 35 facets. Antennomere XI ( Fig. 5 B–C) with relatively deep impression surrounding slightly prominent disc-like protuberance near base, diameter of impression about half of segmental length. Pronotum wider than long, PL 0.40–0.44 mm, PW 0.49–0.52 mm, with fine punctation. Profemora simple, protrochanters and protibiae lacking spur or spine, mesotibiae lacking denticle. Elytra wider than long, EL 0.75–0.80 mm, EW 0.83–0.85 mm, smooth; subhumeral sulci absent. Abdomen wider than long, AL 0.48–0.52 mm, AW 0.78–0.82 mm; abdominal tergite IV (first visible tergite) with discal carinae extending to two-thirds of tergal length; abdominal sternite VII modified ( Fig. 5 D), with apical lamina broadest near middle and obliquely arcuate toward apex. Length of aedeagus ( Fig. 5 F) including parameres 0.42 mm, with right paramere strongly curved mesally, internal sac bearing several sclerotized spines and densely hairy sclerite.

Female. Similar to male; antennomere XI unmodified. Each eye composed of about 24 facets. Measurements: BL 1.95–2.10 mm, HL 0.40–0.45 mm, HW 0.40–0.41 mm, PL 0.38–0.42 mm, PW 0.48–0.51 mm, EL 0.68–0.73 mm, EW 0.78–0.80 mm, AL 0.46–0.50 mm, AW 0.78–0.80 mm.

Distribution. Eastern China: Zhejiang and Jiangxi.

Etymology. The specific epithet ‘ contus ’ means ‘a pike, lance’, referring to the shape of the apical lamina of sternite VII.

Remarks. Populations from the Majian Town and Mingyue Mountain exhibit only slight geographic variation. Apical lamina of abdominal sternite VII of the population from Majian Town ( Fig. 5 D) is slightly more slender than in the population from Mingyue Mountain ( Fig. 5 E). Illustrations of the aedeagus ( Fig. 5 F–G) found in each population are provided here.

Figures

FIGURE 5. Diagnostic characters of Triomicrus contus, male. A. Habitus. B. Antennal club, in dorsal view. C. Same, in lateral view. D. Abdominal sternites VII – VIII (population from Majian Town). E. Same (population from Mingyue Shan). F. Aedeagus, in dorsal view (population from Majian Town). G. Same (population from Mingyue Shan). Scale bars: A = 0.5 mm; B, C = 0.2 mm; D – G = 0.1 mm.