Shilinotrechus intricatus Huang and Tian

Huang, Sunbin & Tian, Mingyi, 2015, New Species and New Record of Subterranean Trechine Beetles (Coleoptera: Carabidae: Trechinae) from Southwestern China, The Coleopterists Bulletin 69 (4), pp. 727-733 : 727-730

Shilinotrechus intricatus Huang and Tian , new species

( Figs. 1–3 , 6)

Holotype. Male. CHINA: Da Dong cave, Jiuxiang, Yiliang , Kunming , Yunnan Province, 25°5′47.12″ N, 103°23′18.7″ E, 1727 m, 7-VII-2013, Mingyi Tian, Wei Lin, Weixin Liu, Haomin Yin and Sunbin Huang leg., deposited in South China Agricultural University , Guangzhou ( SCAU) ; Paratypes: three males and three females, with same data as holotype .

Description. Length 4.52–5.86 mm (mean 5.12 mm) including mandibles, 4.20–5.40 mm (mean 4.76 mm) excluding mandibles; width 1.70–2.05 mm (mean 1.85 mm). Habitus: Very similar to S. fusiformis . Body fusiform ( Fig. 1 ), coloration variable across individuals, ranging from light reddish brown to darker reddish brown. Head: Large, subquadrate, slightly wider than long, HL/HW = 0.81–0.97 (mean 0.89), widest approximately at the level of the anterior supraorbital pores; labrum transverse, emarginate, with 6 setae at apical margin; eyeless; clypeus subtrapezoidal, with 4 setae at apical margin; mandibles falcate, acute, right mandible tridentate, left mandible with 1 serratation

2) Lateral view; 3) Dorsal view.

or none; mentum and submentum fused; submentum covered with transverse row of 10 setae; frons convex, frontal furrows arcuate from base of clypeus to posterior supraorbital pores; genae slightly convex, with several short hairs; supraorbital areas convex, with 2 pairs of supraorbital pores; neck wide, with distinct, shallow anterior constriction; antenna slender, filiform, length reaching to 3/5 of elytra, scape as long as pedicel, antennomere 5 longest, antennomeres 6–10 gradually decreasing in length towards terminal antennomere, which is as long as antennomere 8. Pronotum: Subtrapezoidal, widest at base (in most specimens, but widest at 1/4 to 1/3 from apex in some individuals), pronotum clearly wider than head, PW/HW = 1.19–1.29 (mean 1.22), PW/PL = 1.25–1.36 (mean 1.32), base much wider than front, PbW/PfW = 1.20–1.29 (mean 1.27); apex feebly curved, front angle small and protruding; basal margin almost straight, hind angle blunt and distinctly reflexed upward; dorsum slightly convex, median line distinctly impressed except in apical and basal part; apical transverse impression faint and uneven; basal area flat and wide at middle, gradually narrowing towards hind angles, basal transverse impression deeply impressed and subangulate at middle. Scutellum indistinct. Elytra: Obovate, widest at about the level of 1/3 from base, then gradually narrowed towards apices; much wider and longer than pronotum, EW/PW = 1.64–1.73 (mean 1.69), EL/PL = 3.21–3.71 (mean 3.47), longer than wide, EL/EW = 1.50–1.59 (mean 1.54); basal parts feebly uneven, with pair of basal setiferous pores; shoulders evanescent; sides moderately bordered until 1/2 from base, then gradually narrowed posteriorly and indistinct at the level of preapical dorsal pore, marginal serration feebly clear until 1/2 from base; dorsum gently convex in middle and gradually more steeper towards sides; surface sparsely covered with minute hairs; striae punctate, superficial and evanescent, stria 8 completely absent, intervals flat, interval 3 widest; apical carina sharp, with an apical curved ridge from the site of stria 5 to near suture; chaetatoxal pattern of dorsal pores and marginal umbilicate pores as in S. fusiformis . Ventral surface and legs: Anal ventrite with pair of marginal setae in male but 2 pairs in female, protarsomere 1 in male slightly broader than in female. Male genitalia: Median lobe markedly different from S. fusiformis , shorter and stouter, about 2/9 as long as elytra, falcate and abruptly curved at about 3/7 of length of median lobe, moderately sclerotized ( Figs. 2–3 ); basal orifice large; sagittal aileron small, irregular, and heavily sclerotized; inner sac armed with intricate, sclerotized copulatory piece, which is exceptionally enlarged, twisted, and interlaced with itself; in dorsal view, apical orifice large and twisted, with tip of copulatory piece porrect, apical

F i g. 6. Adult Shilinotrechus intricatus in

Da Dong cave.

lobe absent; parameres thin and elongate, each bearing 6 apical setae.

Remarks. Shilinotrechus intricatus is very similar to S. fusiformis , but is distinguished from the latter by the arcuate frontal furrows of the head (straight in S. fusiformis ); inner sac of aedeagus armed with an intricate copulatory piece, which is exceptionally enlarged, twisted, and interlaced (simple in S. fusiformis ); apical orifice larger and twisted in dorsal view (smaller and less twisted in S. fusiformis ); each paramere bearing six apical setae (only four in S. fusiformis ).

Etymology. The species epithet “ intricatus ” refers to the complicated structure of the copulatory piece in the male genitalia.

Distribution. Known only from the type locality, Da Dong cave in Jiuxiang, Yiliang, Kunming, Yunnan Province, China ( Fig. 4 ). Da Dong is located at the base of a limestone mountain, with a large entrance ( Fig. 5 ) and a main passage. It is moist and decorated by beautiful columns, helictites, and cave flowers. The trechine beetles were collected on substrate or cave walls. The cave holds a rich fauna. Apart from S. intricatus (Fig. 6), there are other cave animals living in the cave, such as millipedes, crickets, harvestmen, snails, moths, centipedes, leeches, and spiders.

Description. Length: 5.42–5.92 mm (mean 5.72 mm) including mandibles, 5.06–5.53 mm (mean 5.34 mm) excluding mandibles; width: 1.80–1.95 mm (mean 1.86 mm). Habitus: Body stout; dark reddish brown ( Fig. 7 ). Head: Fairly large, slightly longer than wide, HL/HW = 1.04–1.08 (mean 1.07), widest between levels of supraorbital pores, little more nearer to posterior supraorbital pore in distance than in S. albidraconis ; labrum transverse, slightly emarginate at apex, with 6 setae; clypeus transverse, with 4 setae at about 3/7 from

Figures

Fig. 1. Shilinotrechus intricatus, habitus.

Figs. 2–3. Shilinotrechus intricatus, male genitalia.

Fig. 4. Distribution map of Shilinotrechus species. a = Dagan Dong; b = Da Dong. ♦ = S. fusiformis; · = S. intricatus.

Fig. 5. Entrance to Da Dong cave, Yunnan Province, China.

Fig. 7. Sichuanotrechus dakangensis, habitus.