Results

Taxonomic account

Tribe Ceruchini

Ceruchus

MacLeay, 1819

91B5AD32-B5B4-5A03-B419-43EEED2B3DDA

• CeruchusMacLeay, 1819: 115. Type species: Lucanus chrysomelinus Hochenwarth, 1785.
• PlatycerusLatreille, 1807: 133. Preoccupied name: Platycerus Geoffroy, 1762 in Lucanidae.
• TarandusMegerle: Dejean, 1837: 194. Nomen nudum in Dejean’s Catalogue des coléoptères de la collection de M. le comte Dejean.

Material examined.

Ceruchus sinensis Nagel, 1933: Holotype. China • 1 ♂; Yunnan Province, near Mt Frances Gardner, west of Mekong, elev. 2438 m, 9.VII.1922; Prof. J.W. Gregory leg.; MNHN. Non-type material. China • 1 ♂; Yunnan Province, Weixi County, Baijixun Township, 1.IV.2021; Zhiwen Yu leg.; AHU.

Ceruchus minor Tanikado & Okuda, 1994: Paratype. China • 1 ♀; Shaanxi Province, Qinling Mountains, Huxian, elev. 1400–1600 m, 33.9167°N, 108.5000°E, 27.VI.1993; Tabana leg.; MNHN. Non-type material. China • 1 ♂; Shaanxi Province, Qinling Mountains, Changan, elev. 1400–1600 m, 11–24.IV.1993; M. Tabana leg.; MNHN. China • 3 ♂ 2 ♀; Shaanxi Province, Mei County, Honghegu, elev. 1600 m, III.2025; Yanchen Liu leg.; AHU.

Ceruchus deuvei Boucher & Král, 1997: Paratype. China • 1 ♀; Sichuan Province, Mts. Siguniang, Huangqiao-gou Valley, southwest of Lixian, elev. c. 2500 m, deciduous forest; MNHN. Non-type material. China • 1 ♂; Sichuan Province, Niuzhihe Fl., Pusiun, elev. 2200 m, 16.VI.2000; Belousov leg.; MNHN.

Ceruchus niger Boucher & Král, 1997: Holotype. China • 1 ♂; Yunnan Province, Zhongdian, elev. 3300 m, Abies forest, VII; Th. Deuve leg.; MNHN. Non-type material. China • 4 ♂ 3 ♀; Yunnan Province, Weixi County, Zhonglu Township, III.2021; Yanchen Liu leg.; AHU. China • 2 ♂ 1 ♀; Yunnan, Shangri-La City, VI.2018; collector unknown; AHU. China • 2 ♂; Yunnan Province, Weixi County, Zhonglu Township, III.2026; Yujie Huang leg.; AHU.

Ceruchus yangi Huang, Imura & Chen, 2011: Holotype. China • 1 ♂; Guizhou Province, Jiangkou County, Mt Fanjingshan, elev. c. 2000 m, 25.X.2009; X.-D. Yang leg.; SHNU. Non-type material. China • 2 ♂; Chongqing, Nanchuan District, Mt Jinfoshan, elev. 1855 m, III.2025; collector unknown; AHU. China • 2 ♂ 1 ♀; Guizhou Province, Leishan County, Mt Leigongshan, elev. 2000 m, IV.2021; Yanchen Liu leg.; AHU.

Ceruchus yingqii Huang & Chen, 2013: Holotype. China • 1 ♂; Sichuan Province, Xiaojin County, Rilong Township, Changping-gou Valley, elev. 3600 m, 6.VIII.2011; H. Huang leg.; SHNU.

Ceruchus ganyanae Huang & Chen, 2017: Holotype. China • 1 ♂; Sichuan Province, Muli County, near Kangwu Pass, elev. c. 3200 m, VI.2011; Ganyan Yang leg.; SHNU.

Ceruchus motuoensis Huang, Chen, Tao & Xiao, 2020: Holotype. China • 1 ♂; Xizang, Motuo County, 62k, elev. 2754 m, 13.XI.2019; R.-C. Tao & C.-M. Xiao leg.; SHNU.

Ceruchus tabanai Okuda, 2008: Non-type material. China • 1 ♂ 1 ♀; Sichuan Province, Puge County Mt Luojishan, III.2026; Yanchen Liu leg.; AHU.

Ceruchus reginae Boucher & Král, 1997: Non-type material. China • 1 ♂; Yunnan Province, Fugong County, Shiyueliang Township, elev. 2900 m, 15.III.2021; Yanchen Liu leg.; AHU.

Description.

Generic characters. Members of the genus Ceruchus are relatively small. Sexual dimorphism distinct. Body mostly reddish-brown or dark brown. Dorsum slightly convex, relatively smooth, and sparsely setose. Venter possesses more pronounced short setae. Compound eyes small and entire, lacking canthus. Antennae stout and not distinctly geniculate; scape relatively stout and curved, forming an angle greater than 90 degrees with pedicel. Pedicel longer than antennomeres 3–7; antennomeres 8–10 dilated, forming a 3–segmented club. Both maxillary and labial palps considerably long; maxillary palps almost equal in length to antennae.

Male. Body length 9.0–21.5 mm. Mandibles not longer than combined length of head and pronotum, slightly curved upwards, hollowed on inner-ventral side, and clothed with relatively long, dense setae; apex of mandibles acute; mandibles with a well-developed major tooth near middle or base, curved upward and directed subhorizontally or obliquely forward; one or two small, subquadrate, inwardly curved obtuse denticles present posterior to major tooth toward base; base of ventral mandibular margin usually with a triangular obtuse tooth directed almost vertically downward. Head relatively broad, with sparse large punctures; an oblique groove formed by a line of punctures present behind each eye; labrum small, usually triangular. Pronotum subrectangular, with distinct small punctures; anterior margin sinuate, posterior margin nearly straight, and lateral margins nearly parallel. Elytra with distinct longitudinal striae formed by punctures. Legs short; tibiae of all legs serrate and armed with sharp denticles; outer apical margin of protibia not bifurcate, bearing only a single acute tooth; inner apical margin with a well-developed spur curved downward; outer apical margins of mesotibia and metatibia without distinct bifurcation, inner apical margins with two asymmetrical outward-curving spurs.

Male genitalia. Internal sac not everted from middle to apex; instead, only a slender sac-like structure present within median lobe. Median lobe broad, forming a large plate with a rounded apex. Parameres plate-like and rounded. Basal piece stout, longer than parameres. Median struts variable in thickness and length.

Female. Body length 9.0–15.5 mm. Mandibles short and small; dorsal margin of mandibular base forming a slightly upward-curved arched plate, apex forming an acute triangular denticle, base obtuse and quadrate, and middle bearing one small denticle, giving arched plate a trifurcate appearance; base of ventral margin without a tooth. Anteromedian portion of vertex with a shallow depression. Pronotum subtrapezoida, distinctly convex and ridge-like, flanked by a small convexity on each side. Setae on inner margin of mandibles, mesofemora, and ventral apex of mesotibiae much less conspicuous and dense than in male. Punctures on head, pronotum, and elytra deeper and denser than in male. Other characters similar to those of male.

Female genitalia. Hemisternites subtrapezoidal and plate-like, bearing small styli at apex. Accessory duct long, broad, and apically spherical. Spermatheca often slightly sclerotized; spermathecal duct relatively thin and short, distinctly separated from and narrower than spermatheca; spermathecal gland slender.

Distribution.

Holarctic.

Ceruchus ahualuo

Huang, Liu & Wan sp. nov.

3EC5E69C-56D6-5658-9976-6C62F28AD62C

https://zoobank.org/AB1D44F9-EA15-4616-99A9-535FB9C8EBAB

Figs 1, 2, 3, 5, 6

Chinese common name.

阿花洛角锹甲.

Figure 1.: Habitus of C. ahualuo sp. nov. A, D. Major male (holotype); B, E. Minor male (paratype); C, F. Female (paratype), dorsal view; A–C. Dorsal view; D, E. Ventral view. Scale bars: 10 mm.

Figure 2.: Lateral view of C. ahualuo sp. nov. A. Major male (holotype); B. Minor male (paratype). Scale bars: 10 mm.

Figure 3.: Genitalia of C. ahualuo sp. nov. A–E. Aedeagus: A. Dorsal view; B. Ventral view; C. Lateral view; D. Median lobe, ventral view; E. Median lobe, lateral view; F. Female genitalia. Abbreviations: ML = median lobe; PA = parameres; C = caudal margin of basal piece of aedeagus; BP = basal piece; ST = strut; SY = styli; HS = hemisternite; MO = median oviduct; BC = bursa copulatrix; SD = spermathecal duct; S = spermatheca; AG = accessory gland; SG = spermathecal gland. Scale bars: 1 mm.

Type material.

Holotype: China • ♂; Yunnan Province: Weixi County, Mts. near Ahualuo River, elev. 2600 m, in decayed logs, 2024-IV-2, Baijun Li leg., deposited in AHU. Paratypes: China • 4♂, 2♀ Yunnan Province: Weixi County, Zhonglu Township, elev. 2750 m; in decayed logs, 2021-III-5, Yanchen Liu leg., (AHU). China • 3♂ Yunnan Province: Weixi County, Mts. near Ahualuo River, elev. 2800–3000 m, in decayed logs, 2026-V, Yujie Huang leg., (AHU).

Description.

Male (Figs 1A, 1B, 1D, 1E, 2). Body length 13.5–17.0 mm. Body black, labial palps, maxillary palps and legs slightly paler. Pronotum wider than long, strongly convex, with relatively broad lateral margins. Elytra with 7 distinct longitudinal striae, humeral angles obtusely rounded. Scutellum semicircular. Legs slender; ventral surface of femora with sparse yellow setae; ventral apex of mesotibiae with a yellow setal brush.

Head with vertex bearing a distinct subconical depression anteromedially. Labrum triangular. Mandibles slender, longer than head, apex acute, inner margin clothed with yellow setae. Base of ventral margin with a triangular obtuse tooth directed vertically downward, smaller in minor individuals; a very small projection present at approximately apical two-thirds of mandibular length, more distinct in minor individuals. Dorsal margin near base with a large finger-like tooth (Fig. 2), curved upward and directed obliquely forward; one subquadrate obtuse denticle positioned immediately posterior to this large tooth toward base and directed horizontally.

Aedeagus. (Fig. 3A–E). Parameres broad and plate-like, with bluntly rounded apices, curved dorsally. Median lobe moderately sclerotized and equal in length to parameres, broadened medially and tapering toward both base and apex. Basal piece stout, longer than parameres. Struts approximately as long as median lobe. Caudal margin of the basal piece of the aedeagus with a shallow median emargination.

Female. (Fig. 1C, F). Body length 10.5–13.5 mm. Dark brown. Mandibles small, shorter than head. Dorsal margin of mandibular base forming a slightly upward-curved arched plate; apex forming an acute triangular denticle, base obtuse and quadrate, middle bearing a very indistinct small denticle, rendering arched plate shallowly trifurcate. Base of ventral margin without a tooth. Anteromedian portion of vertex with a very shallow depression. Pronotum subtrapezoidal, disc distinctly convex and ridge-like, flanked by a small convexity on each side of the elevation. Setae on inner margin of mandibles, mesofemora, and ventral apex of mesotibiae much less conspicuous and dense than in male. Other characters similar to those of male.

Female genitalia (Fig. 3F). Hemisternites subtrapezoidal and plate-like, bearing small styli at apex. Accessory duct long, broad, and apically spherical. Spermatheca slightly sclerotized; spermathecal duct relatively thin and short, distinctly separated from and narrower than spermatheca; spermathecal gland slender.

Diagnosis.

Ceruchus ahualuo sp. nov. is similar to C. niger (Fig. 4A, D), C. sinensis (Fig. 4B, E), and C. yangi (Fig. 4C, F) in body size and the density of setae on the mesofemora, but can be distinguished from them by the large finger-like tooth on the dorsal surface near the base of each mandible. This discrete mandibular character was not observed in other examined species of Ceruchus. In the male genitalia, the new species differs from C. yangi and C. niger by the caudal margin of the basal piece of the aedeagus with a shallow median emargination in ventral view (vs. caudal margin of the basal piece forming an M-shaped margin in ventral view; cf. Fig. 3A and Huang et al. 2011: figs 134–139, 164–169). It also differs from C. sinensis by the median lobe swollen medially in lateral view (vs. median lobe not swollen medially in lateral view; cf. Fig. 3E and Huang et al. 2011: figs 196–201).

Figure 4.: Closely related species in dorsal and lateral views. A, D. C. niger; B, E. C. sinensis; C, F. C. yangi; A–C. Dorsal views; D–F. Lateral views. Scale bars: 10 mm.

Given the sympatric occurrence of C. ahualuo sp. nov. and C. niger, the COI data were used to further assess their separation. In the maximum-likelihood tree based on mitochondrial COI sequences, the new species was recovered as a distinct lineage and was clearly separated from C. niger (Fig. 5). The pairwise K2P distance between the two species was 0.1359, falling within the range of interspecific distances observed among the sampled Ceruchus species and much higher than the distance between the two C. minor sequences (0.0077; Table 2). These molecular results are consistent with the morphological differences described above and provide additional support for separating the new species from the sympatric C. niger.

Figure 5.: Maximum-likelihood tree based on mitochondrial COI sequences of selected Ceruchus species, with Sinodendron yunnanense used as the outgroup. Numbers at nodes indicate branch support values. The new species is highlighted in bold.

 | Taxon | 1 | 2 | 3 | 4 | 5
1 | Ceruchus ahualuo PZ603445.1 |  |  |  |  | 
2 | Ceruchus niger PZ603446.1 | 0.1359 |  |  |  | 
3 | Ceruchus lignarius AB427048.1 | 0.1823 | 0.1741 |  |  | 
4 | Ceruchus minor LC511010.1 | 0.1395 | 0.1272 | 0.1823 |  | 
5 | Ceruchus minor LC511011.1 | 0.1395 | 0.1256 | 0.1733 | 0.0077 | 

Etymology.

The specific epithet ahualuo is a noun in apposition, derived from the name of the type locality of this species.

Distribution.

China: Yunnan.

Key to species of Ceruchus MacLeay from China

1 | Lateral margins of pronotum strongly arcuate | C. luojishanensis
– | Lateral margins of pronotum subparallel | 2
2 | Mesofemora with dense yellow setae, forming a brush | 3
– | Mesofemora with sparse yellow setae, not forming a brush | 6
3 | Base of dorsal margin of mandibles with one incurved obtuse tooth | C. reginae
– | Base of dorsal margin of mandibles with two incurved obtuse teeth | 4
4 | Mandibles curved | C. deuvei
– | Mandibles relatively straight | 5
5 | Obtuse tooth at base of ventral mandibular margin reduced | C. ganyanae
– | Obtuse tooth at base of ventral mandibular margin distinct | C. katerinae
6 | Mandibles robust | 7
– | Mandibles slender | 8
7 | Anterior margin of mentum straight, not protruding medially | C. minor
– | Anterior margin of mentum distinctly protruding medially | C. niger
8 | Obtuse tooth at base of ventral margin of mandibles reduced | C. yangi
– | Obtuse tooth at base of ventral margin of mandibles distinct | 9
9 | Groove formed by punctate line on postocular lateral margin deep, lateral margin of head distinctly undulate | C. motuoensis
– | Groove formed by punctate line on postocular lateral margin shallow, lateral margin of head not distinctly undulate | 10
10 | Large tooth on dorsal mandibular margin finger-like, distinctly extending obliquely forward | C. ahualuo sp. nov.
– | Large tooth on dorsal mandibular margin triangular, directed subhorizontally or only slightly obliquely forward | 11
11 | Elytral longitudinal striae indistinct | C. yingqii
– | Elytral longitudinal striae distinct | 12
12 | Apices of parameres truncate in lateral view | C. tabanai
– | Apices of parameres semicircular in lateral view | C. sinensis