Triomicrus aculeus 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 : 511-512

Triomicrus aculeus Shen and Yin , new species

( Fig. 2 )

Type material (11 ♂♂, 6 ♀♀). Holotype: China: ♂, labeled ‘ China: S. Zhejiang, Lishui City, Longquan (龙泉市), Fengyang Shan N. R. (凤阳山), forest nr. Xiabian Vill. (下边村), 27°55’58’’N, 119°10’57’’E, mixed litter, sifted, alt. 690–780 m, Z. Peng, Y.-M. Yu, Z.-W. Yin leg.’ ( SNUC). Paratypes: China: 4 ♂♂, 1 ♀♀, labeled ‘ China: S. Zhejiang, Lishui City, Fengyang Shan N. R. (凤阳 山), forest nr. Datianping (大田 坪), 27°54’33’’-55’18’’N, 119°10’20’’-17’’E, mixed litter, moss, sifted, 1170–1300 m, 06.x.2013, Feng, Peng, Yu, Yin leg.’ ( SNUC); 4 ♂♂, labeled ‘ China: S. Zhejiang, Lishui City, Longquan (龙泉 市), Fengyang Shan, Datianping, 27°54’36’’N, 119°10’20’’E, bush leaf, moss, ferns, sifted & beating, 1320 m, 27.iv.2014, Peng, Song, Yan, Yin & Yu leg.’ ( SNUC); 2 ♂♂, labeled ‘ China: S. Zhejiang, Qingyuan (庆元县), Mt nr. Liyang Village (栗洋村), 27°49’38’’N, 119°11’22’’E, leaf litter, sifted, 29.iv.2014, 990– 1160 m, Peng, Song, Yan, Yin & Yu leg.’ ( SNUC).

Diagnosis. Antennomere XI with impression surrounding moderately prominent disc-like protuberance near base. Head lacking median vertexal carina. Pronotum relatively smooth. Elytral subhumeral sulci absent. Profemora simple, protrochanters and protibiae lacking spur or spine, mesotibiae lacking denticle. Apical lamina of abdominal sternite VII slender and elongate, apex slightly curved laterally. Aedeagus with right paramere curved mesally, internal sac bearing several sclerotized spines, lacking hairy sclerite.

Description. Male ( Fig. 2 A). Length 2.03–2.11 mm. Head longer than wide, HL 0.45–0.48 mm, HW 0.40– 0.43 mm, lacking median vertexal carina; lateral portions of frons sparsely punctate; each eye composed of about 35 facets. Antennomere XI ( Fig. 2 B–C) with impression surrounding moderately prominent disc-like protuberance near base, diameter of impression slightly less than half of segmental length. Pronotum wider than long, PL 0.40– 0.43 mm, PW 0.48–0.50 mm, relatively smooth. Profemora simple, protrochanters and protibiae lacking spur or spine, mesotibiae lacking denticle. Elytra wider than long, EL 0.73–0.75 mm, EW 0.80–0.84 mm, smooth; subhumeral sulci absent. Abdomen wider than long, AL 0.45–0.46 mm, AW 0.74–0.78 mm; abdominal tergite IV (first visible tergite) with discal carinae extending to three-fifths of tergal length; abdominal sternite VII modified ( Fig. 2 D), with apical lamina slender and elongate, apex slightly curved laterally. Length of aedeagus ( Fig. 2 F) including parameres 0.40 mm, with right paramere curved mesally, internal sac bearing several sclerotized spines, lacking hairy sclerite.

Female. Similar to male; antennomere XI unmodified. Each eye composed of about 20 facets. Measurements: BL 1.90–2.01 mm, HL 0.43–0.45 mm, HW 0.40–0.41 mm, PL 0.39–0.41 mm, PW 0.46–0.49 mm, EL 0.68–0.73 mm, EW 0.79–0.81 mm, AL 0.41–0.43 mm, AW 0.73–0.75 mm.

Distribution. Eastern China: Zhejiang.

Etymology. The specific epithet ‘ aculeus ’ means ‘a sting, spine’, referring to the shape of the apical lamina of sternite VII.

Remarks. Populations from Fengyang Mountain and Liyang Village exhibit only slight geographic variation. Apical lamina of abdominal sternite VII of the population from Fengyang Mountain ( Fig. 2 D) is slightly more slender than in the population from Liyang Village ( Fig. 2 E). Sclerotized spines of the aedeagus of the population from Liyang Village ( Fig. 2 F) are slightly longer than the population from Liyang Village ( Fig. 2 G).

Figures

FIGURE 2. Diagnostic characters of Triomicrus aculeus, male. A. Habitus. B. Antennal club, in dorsal view. C. Same, in lateral view. D. Abdominal sternites VII – VIII (population from Fengyang Shan). E. Same (population from mountain near Liyang Village). F. Aedeagus, in dorsal view (population from Fengyang Shan). G. Same (population from mountain near Liyang Village). Scale bars: A = 0.5 mm; B, C = 0.2 mm; D – G = 0.1 mm.