Stenoscelis brevithoracicus Inoue, 2025

Stenoscelis brevithoracicus Inoue sp. nov.

[New Japanese common name: Miyama-kuchibuto-kikui-zômushi]

urn:lsid:zoobank.org:act:26A1038D-1CD8-4FEB-A6BA-891A7A60C2B8

( Figs 5–6 View FIGURES 1–6 , 12–16 View FIGURES 12–16 , 69 View FIGURE 68–73 & 79 View FIGURE 78–83 )

Diagnosis. Stenoscelis brevithoracicus can be distinguished from the other Japanese congeners by the combination of the following character states: upper margin of scrobe directed to middle of eye ( Fig. 6 View FIGURES 1–6 ); setae on intervals of elytra arranged irregularly, as long as or shorter than granules on declivity ( Fig. 79 View FIGURE 78–83 ).

Description. Body length 3.1–3.8 mm; black, rather shiny; mouth parts, antennae, tarsi, and apical part of tibiae reddish brown; setae yellowish brown.

Rostrum 0.6–0.7 times as long as wide; dorsum rather flat; dorsal surface reticulate, rugosely punctate; punctures small, separated by interspace approximately 1–2 times as long as diameter; upper margin of scrobe directed to middle of eye; epistome with six long setae basally, with anterior margin obtusely projected at right side. Head with dorsal surface reticulate, smoothly punctate; punctures small, separated by interspace approximately 2–4 times as long as diameter; interocular area with a shallow fovea; eye round, hardly convex.

Antennae with club subcircular, slightly wider than long; funicle 7-segmented, slightly longer than club.

Prothorax 0.8 times as long as wide, widest before base, gradually narrowed anteriorly, weakly sinuate laterally; anterior margin weakly sinuate in middle or not; subapical constriction distinct on lateral side, obsolete on dorsal side; disc reticulate, rugosely punctate; punctures medium, separated by interspace almost as long as or narrower than diameter.

Elytra 1.8–1.9 times as long as wide, 1.1 times as wide as and 2.4–2.6 times as long as prothorax, subparallel, conjointly rounded at apex; apex obtusely angulated in lateral view; striae rather deep, with medium punctures separated by interspace approximately 1–2 times as long as diameter; apical part of striae moderated, not dilated or reticulate; second stria distinctly separated from base; intervals somewhat convex, with an irregular row of small puncture; base of second to third or fourth interval rugosely punctate-granulate; apical half of ninth interval and tenth interval carinate; granules of intervals arranged in a single row, indistinct basally, distinct and conical on declivity; setae on declivity arranged irregularly in two or three rows, as long as or shorter than granules.

Aedeagal body ( Figs 12, 13 View FIGURES 12–16 ) 2.0 times as long as wide, 1.5 times as long as apodeme, subparallel, rapidly narrowed and weakly prolonged apically; apodeme attached laterally; endophallus with a pair of spinulate sclerite on subapical part and a U-shaped sclerite on basal part; tegmen ( Fig. 14 View FIGURES 12–16 ) without dorsal part and paramere, with distinct manubrium; spiculum gastrale ( Fig. 15 View FIGURES 12–16 ) gradually curved to right side apically, not expanded apically; sternite VIII divided, with several long setae apically; without spinulate apical membranous area.

Spiculum ventral not bifurcate at base; spermatheca ( Fig. 16 View FIGURES 12–16 ) with cornu falciform; collum rather developed; ramus not developed.

Distribution. Japan: Honshu, Shikoku, and Kyushu.

Biological note. The adults were collected from tunnels bored in the fallen branch of a broad-leaved tree ( Fig. 85 View FIGURE 84–89 ) at Mt. Hikosan, Fukuoka Prefecture (Naomichi Tsuji pers. comm.).

Etymology. The new species is named after its relatively shorter prothorax.

Type material. Holotype: male ( KUM), “ ạ̎āƂmōīƂḃšŝ山 / 33.481°N, 130.928°E / Mt. Hikosan, Soeda-machi , / Tagawa-gun, Fukuoka Pref., / Kyushu, Japan, 2 V 2016, / Yu HISASUE leg.” (white card); “HOLOTYPE / Stenoscelis / brevithoracicus / des. S. Inoue, 2024” (red card) GoogleMaps . Paratypes: Honshu: [Aomori Pref.]: 1 unsexed, Mt. Yasuteyama, Hiraka-machi , 22.V.1999, T. Ozaki leg. ( KUM); [Miyagi Pref.]: 1 unsexed, Hatasaka, Taiwa-chô , 18.V.2013, T. Ozaki leg. ( KUM); [Fukushima Pref.]: 1 unsexed, Shinden-bara, Tateiwa-mura , 24.VI.1990, K. Yoshihara leg. ( KUM) ; [Tochigi Pref.]: 1 unsexed, Yumoto, Nasu T ., 12.V.2000, T. Nakamura leg. ( KUM) ; [Fukui Pref.]: 1 unsexed, Ikegahara, Ohno , 4.VI.1989, Y. Takai leg. ( KUM) ; [Kyoto Pref.]: 1 unsexed, Kyoto University Research Forest, Miyama , 31.V.2010, J. Aoki leg. ( KUM) ; Shikoku: [Ehime Pref.]: 4 unsexed, Komenono , 5.V.1976, Y. Notsu leg. ( EUM) ; 1 unsexed, ditto, 22.V.1976, Y. Notsu leg. ( EUM) ; Kyushu: [Fukuoka Pref.]: 1 female, Mt. Hiko-san, Soeda-machi , 2.V.2016, Y. Hisasue leg. ( KUM) ; 2 male, 4 female, Mt. Hiko-san (alt. 650 m), Soeda-machi , 16.XI.2020, N. Tsuji leg. ( KUM) ; 1 unsexed, Hikosan, Soeda-machi , 3.IV.2021, T. Nozaki leg. ( KUM) ; 1 unsexed, Mt. Ishiwari-dake , Hoshino-mura, Yame-gun, 7.V.2000, K. Kido leg. ( KUM) ; [Ôita Pref.]: 1 male, 1 female, 1 unsexed, Tsukahara, Yufuin-chô , 15–16.IV.2016, R. Ito leg. ( KUM) .

Remarks. This species is rather unremarkable, and difficult to distinguish from the species that have the upper margin of the scrobe directed to middle of eye. Comparing the descriptions in the literature, I concluded it is a new species based on the following differences: among the species from China and the Himalayan region, S. chinensis Voss, 1955 may be distinguished from S. brevithoracicus by the apex of elytra being slightly protruding, S. himalayensis and S. recavus Zhang, 1995 by having the distinct transverse depression between head and rostrum, and S. yuxianensis Zhang, 1995 by the rostrum being twice as wide as long ( Stebbing, 1914; Voss, 1955; Zhang, 1995); among European species, S. submuricatus (Schoenherr, 1832) may be distinguished by the pronotum being as long as wide and the elytral apex being separately rounded, and S. subasperatus (Reitter, 1898) by the pronotum being as wide as elytra and the midline of pronotum being without punctation (Reitter, 1898; Voss, 1955; Folwaczny, 1973).