Stephostethus chinensis ( Reitter, 1877 )

Ho, Yu-Hsiang, Rücker, Wolfgang H. & Chan, Mei-Ling, 2021, On the genus Stephostethus LeConte, 1878 (Coleoptera: Latridiidae: Latridiinae) from Taiwan, with descriptions of two new species, European Journal of Taxonomy 735 (735), pp. 1-14 : 8-11

Stephostethus chinensis ( Reitter, 1877)

Figs 7–9 , 11–14

Lathridius chinensis Reitter, 1877: 113 .

Stephostethus chinensis – Rücker 2018: 172.

Diagnosis

Stephostethus chinensis ( Reitter 1877) is similar to S. carinatus Sen Gupta, 1976 from India. However, the former species can be distinguished from the latter by the structure of the genital segments of the

male, and the characters of the teeth on male tibiae, as S. carinatus has one tooth on the mid tibia, and S. chinensis has no teeth on the mid tibia.

Material examined

TAIWAN • 2 ♂♂; Nantou County, Ren’ai , Meifeng ; 24.0973° N, 121.1764° E; 2113 m a.s.l.; 30 Mar.–1 Apr. 2020; F.S. Hu and Y.J. Chen leg.; by flight interception trap; PCHO • 1 ♂; Nantou, Meifeng ; 3–15 Oct. 1990; C.K. Starr leg.; yellow pan trap; NMNS ENT 766-5 • 1 ♂; Nantou, Jenai, Meifeng ; 12 Nov.– 10 Dec. 2002; C.S. Lin and W.T. Yang leg.; Malaise trap; NMNS ENT 4913-1077 • 1 ♂; Kaoshiang [Kaohsiung, mistyped] (TM7), Tengchih ; 9–18 Feb. 2009; C.T. Yao leg.; TARI • 1 ♀; Kaoshiang [Kaohsiung, mistyped] (TM3), Tengchih ; 9–18 Feb. 2009; C.T. Yao leg.; TARI • 1 ♂; Kaohsiung City, Taoyuan, Shishan logging trail ; 8 Feb. 2020; C.T. Hsu leg.; beating; PCHO • 2 ♂♂; Taitung Hsien, Chihpen ; 17–18 Feb. 1982; L.Y. Chou and K.C. Chou leg.; TARI .

Description

LENGTH. 1.83-2.00 mm.

WIDTH. 0.86-0.97 mm.

COLOUR. General body colour brown to dark brown, with legs and antennae yellowish brown.

HEAD. Slightly longer than wide, width to length ratio 1.00: 1.20, surface strongly punctate, base of head depressed, clypeus narrower than head, covered with some short setae; temple narrower than eye, about half length of eye, with sharp hind angle. Antennae 11-segmented, second segment slightly shorter than third segment, apical three segments clubbed. Eyes strongly developed, with more than 20 facets. Sometimes covered with wax in ventral view.

PRONOTUM. Slightly wider than long, width to length ratio 1.00: 0.95; sides almost parallel, widest at anterior margin, narrowest at posterior one-third. Front angle slightly protruded and bluntly rounded, anterior third with a pair of triangular depressions. Surface irregularly and densely punctate, with a pair of carinae on disc. Prosternum short, procoxa separated. Sometimes covered with wax in ventral and lateral views.

ELYTRA. Broadly oval, width to length ratio 1.00: 1.40, broadest at middle, apex round. Posterior third depressed. With eight punctate striae, 1 st striae complete, 2 nd striae connected with 7 th striae at posterior end of elytra, 3 rd striae connected with 6 th striae, 4 th striae connected with 5 th striae, 8 th striae incomplete. 5 th interstriae weakly carinate, 7 th interstriae strongly protruding at front, and extended to middle, with short setae. Scutellum broadly pentagonal.

METASTERNUM. Strongly convex, with fovea situated under mid coxa on each side and surrounded by radial striae. Sometimes covered with wax on meso- and metasternum.

LEGS. Long and slender, covered with short setae on femora and tibiae. Tarsi 3-3-3, tarsomere 3 longer than 1 and 2 combined; arolium indistinct. Male protibia expanded and curved at apex, with one distinct tooth on anterior end; mid tibia straight, without any teeth; hind tibia straight, with three distinct teeth on anterior end. Female without any teeth on legs.

MALE GENITALIA. Aedeagus weakly chitinized. Long and slender, sides parallel, sharp at apex; bent at anterior two fifths, and weakly curved at anterior fifth. Genital segments broad and short, broadest at base, apical end deeply concave with two rounded lobes ( Fig. 8 ).

Distribution

This species is only known from Asia, including Eastern Siberia, China, Japan and Mongolia ( Johnson 2007; Rücker 2018, 2020), and is new to Taiwan ( Fig. 12 ). It is distributed in mid to southern Taiwan, and is widely recorded in various areas, ranging in altitude from 300 to 2300 m a.s.l.

Remarks

Stephostethus chinensis was recorded as a household pest in Japan ( Tanaka & Tahira 1995). However, we have never found this species in indoor environments in Taiwan. Some specimens of this species were collected by beating damp leaves in an artificial red oak forest (~ 1700 m a.s.l.), and some were collected with flight interception traps in the forest (2113 m a.s.l.) ( Fig. 11 ).

Figures

Figs 7–9. Stephostethus chinensis (Reitter, 1877) (TARI). 7. Habitus, dorsal view. 8. Male genital segments, dorsal view. 9. Male tibiae, A = protibia, B = midtibia, C = hindtibia. Scale bars: 7 = 0.5 mm; 8–9 = 0.1 mm.

Figs 10–12. Habitat and distribution map of Stephostethus LeConte, 1878 in Taiwan. 10. Habitat of S. yuanfengensis sp. nov. 11. Habitat of S. chinensis (Reitter, 1877) (photo courtesy of F.S. Hu). 12. Distribution map of species of Stephostethus in Taiwan: S. taiwanus sp. nov. (open circle), S. yuanfengensis sp. nov. (open square), S. chinensis (open star).

Figs 13–14. Structure of genital segments of Stephostethus chinensis (Reitter, 1877). 13. Dorsal view. 14. Ventral view. Abbreviations: TG = tergite; ST = sternite.