Stephostethus taiwanus, Rücker & Chan, 2021

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 : 3-5

Stephostethus taiwanus sp. nov.

urn:lsid:zoobank.org:act:35987EB7-6F55-4EB3-B5C0-4DAC0F3D049C

Figs 1–3 , 12

Diagnosis

This species is closely related to Stephostethus chinensis ( Reitter, 1877) , but can be distinguished by the 7 th interstriae, which are less protruding at the front, the structure of the genital segments of the male, and the characters of the teeth on the male tibiae. Stephostethus taiwanus sp. nov. has four indistinct teeth on the hind tibia, whereas S. chinensis has three distinct teeth on the hind tibia.

Etymology

The specific epithet, taiwanus , is named after its country of discovery, Taiwan.

Material examined

Holotype

TAIWAN • ♂; Nantou, Yuanfeng ; 8 Dec. 2005 – 3 Jan. 2006; C.S. Lin and W.T. Yang leg.; Malaise trap; NMNS ENT 7408-4 .

Paratypes

TAIWAN • 1 ♂; Taipei, Wulai, Happen ; 9 Dec. 1985; C.C. Chiang leg.; sweeping net; NMNS ENT 2493-33 • 1 ♂; Miaoli, Taian ; 19 Dec.1989; K.W. Huang leg.; sweeping; NMNS ENT 1113-219 • 1 ♂; Taichung City, Shei-Pa National Park ; 24.38329° N, 121.28631° E; 2 Apr. 2010; W.B. Yeh leg.; sweeping shrub; WRCN • 1 ♂; Taichung City, Shei-Pa National Park ; 24.38985° N, 121.27618° E; 9 Feb. 2011; W.B. Yeh leg.; sweeping shrub; WRCN • 1 ♂; Nantou, Yuanfeng ; 7 Mar.–13 Apr. 2006; C.S. Lin and W.T. Yang leg.; Malaise trap; NMNS ENT 7421-68 • 1 ♂; same collection data as for preceding; 9 May–6 Jun. 2006; NMNS ENT 7421-1099 • 1 ♂; same collection data as for preceding; 3 May–7 Jun. 2005; NMNS ENT 7388-390 • 1 ♂; same collection data as for preceding; 8 Nov.–8 Dec. 2005; NMNS ENT 7393-1096 • 1 ♂; Nantou Hsien, Tsuifeng ; 2300 m a.s.l.; 8 Nov. 1981; S.C. Lin and W.S. Tang leg.; TARI • 1 ♂; Nantou County, Xinyi, Tatajia ; 27 Mar. 2018; H.T. Yeh leg.; in Picea forest; PCHO • 1 ♂; Chiayi Hsien, Alishan ; 2400 m a.s.l.; 17–20 Aug. 1982; K.C. Chou and C.C. Pan leg.; TARI • 1 ♂; Tainan City, Sinhua Forest Area , 15 Feb. 2020; Y.H. Ho leg.; beating dead dry branches; PCHO • 1 ♂; Taitung, Peinan, Panchiu Station , 16 Dec. 2004 – 17 Feb. 2005; C.S. Lin and W.T. Yang leg.; Malaise trap; NMNS ENT 5871-99 .

Description

LENGTH. 1.82–2.05 mm.

WIDTH. 0.87–0.95 mm.

COLOUR. General body yellowish brown to dark brown, with tibiae, tarsi and antennae light brown.

HEAD. Slightly longer than wide, width to length ratio 1.00: 1.11; strongly punctate, clypeus narrower than head, with short setae. Eyes well developed, with more than 20 facets; temple narrower than eye, about half length of eye, hind angle of temple with or without a sharp tooth. Antennae with 11 segments, 3 rd segment slightly shorter than 4 th segment, 4 th to 8 th segment same in length; apical three segments clubbed.

PRONOTUM. Almost as long as wide, width to length ratio 1.00: 0.94; sides almost parallel, widest at anterior margin, narrowest at posterior one-third. Front angle barely protruding and bluntly rounded, posterior one-third with a pair of depressions. Surface irregularly and densely punctate, with a pair of carinae on disc. Sometimes covered with wax on lateral and ventral sides.

ELYTRA. Broadly oval, width to length ratio 1.00: 1.41, broadest at middle, apex round. Depression on posterior one third indistinct. With eight punctate striae, 1 st striae complete, 2 nd striae connected with 7 th striae at posterior end, 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 weakly protruding at front, extending to middle. Sides weakly carinate. Scutellum broadly pentagonal, much wider than long.

METASTERNUM. Strongly convex, each side with fovea situated under mid coxa, 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. Male with one distinct tooth on anterior end of protibia and four indistinct teeth on anterior end of hind tibia, sometimes barely visible, mid tibia without any teeth; anterior end of protibia straight, apex expanded, mid and hind tibia straight.

MALE GENITALIA. Aedeagus weakly chitinized, long and slender, sides parallel, with apex sharp, curve at middle in lateral view. Genital segments weakly chitinized, with apical end truncate, broadest at base ( Fig. 2 ).

Distribution

Taiwan ( Fig. 12 ). Widely found in various altitude levels ranging from 100 to 2300 m a.s.l.

Remarks

This species is widely distributed in Taiwan, and partly overlaps with the range of S. yuanfengensis sp. nov. in central and southern Taiwan. So far, of the three species of Stephostethus LeConte in Taiwan, only S. taiwanus sp. nov. is found in northern Taiwan. Some of the specimens were collected by beating the dead dry branches in a broadleaf forest (~ 100 m a.s.l.).

Figures

Figs 1–3. Stephostethus taiwanus sp. nov. paratype (TARI). 1. Habitus, dorsal view. 2. Male genital segments, dorsal view. 3. Male tibiae, A = protibia, B = midtibia, C = hindtibia. Scale bars: 1 = 0.5 mm; 2–3 = 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).