The genus Gastrocentrum was included in the Philocalus genus group close to the genus Isocymatodera (Gerstmeier 2005; Gerstmeier and Weiss 2009). Both genera have the claw with one inner denticle, which is similar to and only very slightly smaller than the apical portion of the claw (Fig. 20F). The genus Gastrocentrum can be differentiated from Isocymatodera by antennae broadly expanded laterally from 7^th or 8^th antennomeres onwards, the connecting membrane of male aedeagus specialized in both dorsal and ventral surface, the female vagina devoid of sclerites. While in Isocymatodera, the antennae are expanded laterally from 3^rd or 4^th antennomeres onwards, the connecting membrane of male aedeagus is only specialized in dorsal surface, and the female vagina possesses sclerites.

General appearance: body length 9–29 mm; oblong, somewhat robust; all the species except G. laterimaculatum uniformly dark brown (Figs 1–9); vested with long, yellow setae all over the body. Head: hypognathous, moderately large, including eyes slightly broader than pronotum; eyes sizable, emarginate, coarsely faceted, ocular notch small, distance of eyes as long as or only slightly greater than transverse diameter of eyes; gula broad, gular sutures parallel or slightly converging in anterior; antenna comprised of eleven antennomeres, broadly expanded laterally from 7^th or 8^th–11^th, the expanded antennomeres triangular except the last one cultriform, all the expanded antennomeres clothed with fine and dense pubescence; labrum emarginate, mandibles stout with inner dens, terminal segment of maxillary palpi digitiform, that of labial palpi broadly securiform. Thorax: pronotum long campaniform, constricted posteriorly, anterior transverse depression feeble, surface punctate, faintly wrinkled, clothed with long, yellow hairs; pro-intercoxal process thin. Elytra: oblong, sides parallel, anterior ridge present from humerus to scutellum; inner surface with a wedge-shaped protuberance at lateral middle of each elytron (Fig. 20A, B), leaning to the lateral side of first ventrite of abdomen in resting position (except for two species: G. xiaodongi and G. zayuense), and with a microtrichia field on anterio-lateral area (Fig. 20A, mt; similar to the structure found in Tenebrionidae, Gorb, 2001: 125, fig. 8.1, EAL); elytra have two types of punctations: asetiferous and setiferous punctations, the former comprised of primary asetiferous punctation (PAP) and accessory asetiferous punctation (AAP); each elytron possesses ten rows of PAP in general, the fifth row situate just before the humerus (Fig. 10C, D), sometimes PAP vanish in lateral elytron (in G. zayuense and G. gaoligongense, Fig. 10E–H); AAP may present on the interspaces between 1^st–2^nd, 3^rd–4^th, and 5^th–6^th PAP rows and similar with PAP in size, making these two types of punctations more or less indistinguishable (Fig. 10A, B); setiferous punctations minute, bearing setae, densely dispersed over the whole elytral surface, not in rows. Legs: tibia without longitudinal ridge, tibial spur formula 1–2–2 (but in G. laterimaculatum 0–2–2), protibia without tooth at outer apex (except in G. unicolor and G. laterimaculatum where protibia possess a blunt tooth at outer apex); tarsi formula 5–5–5, first to fourth tarsomeres of all legs more or less bilobed and bearing evident pulvilli; claw with one inner denticle, which similar to and only very slightly smaller than apical portion of claw (Fig. 20F). Abdomen: abdomen longer than broad, parallel in front and tapering in rear; first to fifth abdominal ventrites each with a pair of short longitudinal ridges (Fig. 20D) and a pair of less pigmented circles (Fig. 20C) in lateral; sixth ventrite partly or totally slid under the fifth, so in parts of specimens only five ventrites visible; intercoxal process of the first ventrite keel-like, with or without longitudinal groove; first ventrite strongly ridged behind metacoxae. Male genitalia: pygidium subquadrate; sixth ventrite subtriangular to semicircle, posterior margin somewhat rounded, secondary sexual modifications slight (Figs 11F, G, 13G, 15H, 17G, 19G); central parts of sixth ventrite membranous, shape of membranous region different among species; spicular fork well developed, plates slender, apodemes not fused centrally, longitudinal intraspicular plate present (Figs 11D, 13E, 15F, 17E, 19E); tegmen tubiform, sclerotized from dorsal midline to lateral sides, barely sclerotized and unpigmented in ventral middle, tegmen lobed distally, parameres bent to ventral direction, tip simple or hooked, phallobasic apodeme present (Fig. 15B, C); phallus comprised of two thin phallic plates devoid of dentations, an interphallic plate present on the membrane between the two phallic plates (Fig. 11C, H, ipp), phallus apex simple, knot-like, phallic struts long and slender; connecting membrane between tegmen and phallus well sclerotized and thickened except the dorsal midline and ventral midline, forming a nearly whole sheath covering the phallus, which surface densely equipped with microhooks (Fig. 11A–C). Female reproductive organs: pygidium subquadrate; sixth ventrite sub-triangular, disc membranous (Figs 12H, 14B, 16C, E, 18C), spiculum ventrale present; ovipositor as long as abdomen, moderately sclerotized, light yellow, semi-transparent (Figs 12F, 14C, D, 16A, F, 18A, ovp), with proctigeral bacculi in dorsal surface (Fig. 16F, pgb) and ventral and oblique bacculi in ventral surface (Fig. 14C, vtb, olb); vagina and alimentary canal partially enclosed in ovipositor, unenclosed part of vagina as long as or slightly longer than ovipositor, tubular or saccular; bursa copulatrix clearly defined and positioned distally (Figs 12F, 16A, 18A, bc) with the exception of the species G. gaoligongense, where bursa copulatrix is a mere swollen continuation of the vagina (Fig. 22E); spermatheca attached to the base of bursa copulatrix, boundary between spermathecal duct and spermathecal capsule somewhat obscure (Figs 16G, 21), spermathecal duct slender (Fig. 16A) or sometimes inflated in distal and continuous with spermatheca (Figs 16G, 18A), spermathecal capsule moderately to minimally sclerotized, both spermathecal duct and spermathecal capsule with spiral micro-texture, distal part of spermathecal capsule strongly bent, angled no more than 90° (Fig. 16A, G), spermathecal gland duct inserted at the outer edge of the angle (Fig. 21, spgd); in ground-plan, spermathecal gland have three tail-like endings: one located distally, opposite to its opening to spermatheca (top tail, Figs 12E, 14C, spgtt), the other two situated laterally (lateral tail, Figs 12E, 14C, spglt), any of which may be missing in different species and sometimes can be extremely long (Fig. 14C, spglt).

Figures 1–9. 

Habitus. 1 Gastrocentrum magnum sp. nov. Holotype 2 G. dux from Australia 3 G. unicolor (Lectotype of G. pauper) 4 G. regulare sp. nov. Holotype 5 G. xiaodongi sp. nov. Holotype 6 G. zayuense sp. nov. Holotype 7 G. gaoligongense sp. nov. Holotype 8 Tillus nitidus comb. nov. Holotype 9 Isocymatodera atricolor Syntype. Scale bars: 5mm (1, 2) 2mm (3–9).

Figure 10. 

Drawing of elytral asetiferous punctations. A Gastrocentrum magnum sp. nov. B G. dux C G. regulare sp. nov. D G. xiaodongi sp. nov. E G. gaoligongense sp. nov. F–H G. zayuense sp. nov. The numbers 1–10 annotate the serial rows of primary asetiferous punctuations (PAP). Abbreviations: a accessory asetiferous punctations.

Indian subcontinent to Indochinese Peninsula and south through Malay Archipelago to Australia, including the following countries: India, Sri Lanka, Philippines, China, Vietnam, Laos, Malaysia, Indonesia, Australia (Fig. 25).

Lectotype of G. pauper designated herein (Fig. 3): “Gorham Type / Phillipine Isles, Luzon, Semper / Gastrocentrum pauper Gorh. [hw. by Gorham] / Museum Paris, Coll. Gorham, 1914” (MNHN, male, dissected); Paralectotype of G. pauper: “Gorham Type / Camiguin de Luzon / Gastrocentrum genus novum, G. pauper Gorh. [hw. by Gorham] / Museum Paris, Coll. Gorham, 1914” (MNHN, 1 female, dissected).

China: Taiwan: 1994-VII-30, Taiwan, Taoyuan County, Fuxing Township, Shang Baling, 1200 m (CCCC, 1 male, dissected); 2005-IX-4, Taiwan, Taidung County, Beinan Township, Lijia Forest Trail, 1300 m, W-I. Chou leg. (CCCC, 1 male, dissected); 11-IX-1996, Taiwan, Pingtung County, Kenting National Park, W. I. Chou leg. (CCCC, 1 male, dissected); Taiwan, Formosa, IV, Gastrocentrum unicolor White (pauper Gorh.), Museum Paris Coll. M. Pic (MNHN, 1 female); Hainan: Hainan, Wuzhi Mountain, 2011.IX.20, BI Wenxuan (CBWX, 1 female, dissected); Hainan Prov., Baisha, Nankai Town, on vegetation or ground, 18.9741°N, 109.2956°E, 790 m, 2010.4.13 D, Lin Meiying coll. (IZAS, 1 female, dissected). Vietnam: “Museum Paris, Tonkin N., Env. d’Ha-giang, Lieut. Col. Bonifacy 1913” (MNNH, 1 female, dissected). Laos: “Laos-NE, Houa Phan prov., 20°13'09–19"N 103°59'54"-104°00'03"E, 1480–1550 m, PHOU PANE Mt., 1.-16.vi.2009, Zdeněk Kraus leg./NHMB Basel, NMPC Prague, Laos 2009 Expedition: M. Brancucci, M. Geiser, Z. Kraus, D. Hauck, V. Kuban” (NHMB, 1 female, dissected). Thailand: N. Thailand, Meo Village, near Chiang Mai, V.1998 (RGCM, 1 ex.); Thailand, Corat, 26.III.1988 (RGCM, 1 ex.); Thailand, Chiangmai, Doi Pui, 12.VI.1985 (RGCM, 1 ex.). Malaysia: Peninsular Malaysia: Bukit Kutu, Selangor, April 1915, 3457 / ex. Coll. Zoologisch Museum Amsterdam (MNHN, 1 male, dissected); Malaysia, Pahang, Cameron Highlands, Tanah Rata vill. env., Gunung Jasar [Mt]; 1470–1705m, 04°28.4–7'N, 101°21.6–22.1'E, Jiří Hájek leg., 18.iv–10.v.2009 (NMPC, 1 female, dissected); East Malaysia: Elopura, N.-E. Borneo, W. B. Pryer. / Museum Paris ex Coll. R. Oberthur (MNHN, 2 males 1 female, dissected); Borneo, Sabah, Keningau district, Jungle Girl Camp. 5.4430°N, 116.4512°E; 1182 m; Shi H. L. & Liu Y. lgt. light trap, night, 2016.IV.25 (2 ex.), 2016.IV.29 (3 ex.), 2016.IV.30 (1 ex.), 2016.V.1 (1 ex.), 2016.V.2 (3 ex.) (FBFU). Indonesia: W. Celebes, G. Rangkoenau, J. P. Ch. Kalis, 900 ‘. 1937 (MNHN, 5 males, 4 females in total, of which 3 males, 4 females dissected); W. Celebes, Loda, Paloe, J.P. Ch. Kalis, 4000 ‘. 1937 (MNHN, 1 male, dissected); W. Celebes, Sjdaonta Paloe, J. P. Ch. Kalis, 4500’. 1937 (MNHN, 1 male, dissected); Bonthain, Celebes 8. ‘38 (MNHN, 1 male, dissected).

This species has the broadest distribution range in this genus. It is different from G. magnum sp. nov., G. dux sp. nov. and G. regulare sp. nov. in antennae broadly extended laterally from 8^th antennomere onwards (Fig. 11I); different from G. xiaodongi sp. nov., G. zayuense sp. nov., and G. gaoligongense sp. nov. in having AAP on interspaces between elytral 1^st–2^nd, 3^rd–4^th, and 5^th–6^th PAP rows.

Figure 11. 

Gastrocentrum unicolor. A–F Lectotype of G. pauper. A aedeagus in dorsal view B aedeagus in ventral view C aedeagus in lateral view D spicular fork E pygidium F sixth ventrite. G, H specimen from Sulawesi. G sixth ventrite H phallus enveloped by connecting membrane, ventral view h apex of tegmen, ventral view I antenna. Abbreviations: ipp interphallic plate. Scale bar: 1 mm.

(based on type specimens of G. pauper and other specimens from SE Asia only). General appearance: length 9–16 mm, oblong, robust, uniformly dark brown. Head: including eyes feebly broader than pronotum; eyes moderately large, distance between eyes faintly larger than the transverse diameter of eye; gular suture parallel; antennae expanded laterally from 8^th antennomere onwards (Fig. 11I); vertex and frons densely punctate, postgenae rugose. Pronotum: oblong, length/width ratio ca. 1.4, constricted posteriorly; surface densely punctate, faintly rugose, clothed with long, yellow hairs. Elytra: oblong, sides subparallel, length/width ratio ca. 2.3, vested with dense light yellow or off-white setae; wedge-shaped protuberance present on inner surface (Fig. 20A, B); asetiferous punctations arranged in more than ten rows, PAP in ten rows, AAP on interspaces between 1^st-2^nd, 3^rd-4^th, and 5^th-6^th PAP rows, AAP setting in two rows on each interspace; AAP almost same size as PAP; interspace between 2^nd-3^rd PAP rows much wider than punctation diameter; both PAP and AAP beginning to decrease in size postmedially to apical third, and completely vanished at apical fourth to fifth. Legs: outer apex of protibia extending outwards and forming a blunt tooth. Abdomen: intercoxal process of the first ventrite conspicuously grooved longitudinally. Male genitalia: pygidium subquadrate, posterior margin rounded (Fig. 11E); sixth ventrite sub-triangular, ca. 2 × as broad as long, posterior margin more or less angulate, central membranous region pentagonal or subquadrate, extending from anterior margin to posterior margin (Fig. 11F, G); tegmen with phallobasic apodeme 0.6 time as long as phallobase (Fig. 11A–C); paramere apices simple, petty, unhooked (Fig. 11A, h); interphallic plate slightly shorter than half length of phallus (Fig. 11C, H, ipp); phallus apex usually knot-like, 2~3 × as long as wide (Fig. 11H). Female reproductive organs: pygidium slightly broader than long, posterior margin rounded (Fig. 12G); sixth ventrite 2.7 × broader than long, central membranous region elliptical, apical accessory membranous region petty (Fig. 12H); vagina swollen in well-preserved specimens, bursa copulatrix clearly defined (Fig. 12F), spermathecal gland with a top tail of medium length and two lateral tails that almost reduced (Fig. 12A–E); spermatheca boot-shaped in general (Fig. 12A, C–E).

The tegmen apices of G. unicolor are simple, unhooked, unspecialized (Fig. 11A). However, specimens from Sulawesi with tegmen apices slightly more prominent than those from other regions. Phallus apex is normally knot-like with the two phallic plates convergent at a point before the tip (Fig. 11H), but in the holotype of G. pauper, edges of the two phallic plates are almost parallel to the tip (Fig. 11B). The apical tip of phallus is longer than broad, with length/width ratio varied in a range of 2.0~3.0; usually teardrop-shaped with length/width ratio 2.0~2.5, but oblong in specimens from Sulawesi with length/width ratio approximate to 3.0 (Fig. 11H).

Both of the two female specimens examined from Hainan has spermatheca tubiform (Fig. 12B), which is different from those from other localities with spermatheca inflated distally (Fig. 12A, C, D). However, given its same external structure and lacking male specimens, we consider the specimens from Hainan as the same species with G. unicolor.

Figure 12. 

Gastrocentrum unicolor female reproductive organs specimens from different localities. A from Laos B from Hainan C from Philippines, Lectotype of G. pauper D from Borneo E from Sulawesi F from Borneo G pygidium H sixth ventrite. Abbreviations: bc bursa copulatrix cov common oviduct i.e. median oviduct ovp ovipositor sp spermatheca spg spermathecal gland spgtt top tail of spermathecal gland spglt lateral tail of spermathecal gland va vagina.

This species is widespread, from Indian subcontinent to Indochinese Peninsula, south to Malay Archipelago, including the countries and regions: India, Sri Lanka, Philippines, China (Taiwan, Hainan), Vietnam, Laos, Thailand, Malaysia (Peninsular Malaysia, Sabah), Indonesia (Sulawesi).

Gahan (1910) proposed that G. pauper was a junior synonym of G. unicolor without explanation, which treatment was afterward followed by Schenkling (1912), Chapin (1924), Corporaal (1950), and temporarily by Mawdsley (1999) and the present paper. In our research, we have only examined specimens from SE Asia and determined they are identical with G. pauper. However, additional materials from India or Sri Lanka need to be compared with those from SE Asia thoroughly, which will lead to the confident assignment of the synonymy.

Malaysia: H. C. Siebers, M. O. Borneo Exp. Long Hoet, 3.VIII.1925 (ZMAN, 1 ex.); Borneo, Sabah, Keningau district, Jungle Girl Camp., 5.4430°N, 116.4512°E, 1182m, Shi H. L. & Liu Y. lgt. light trap, 2016. V. 1. N (FBFU, 1 male); Malaysia, N. Borneo, Sabah, Keningau distr., Trus Madi Mt., h = 1160 m, leg. J. Chew, 20.VI.2011 (RGCM, 1 ex.).

This species is the only one in this genus that has elytral pattern and can be separated from other species without difficulty. Its elytra is yellow-brown, with a pair of large semicircular dark spots in lateral sides which is extended to the lower sides of humeri; elytral asetiferous punctations larger than other species, with punctation diameter greater than interspace between 2^nd-3^rd PAP rows; antennae broadly extended laterally from 8^th antennomere onwards.

Elytral wedge-shaped protuberance present on inner surface; elytral asetiferous punctations somewhat irregular, arranged in more than ten rows, PAP in ten rows, AAP on interspaces between 1^st–2^nd, 3^rd–4^th, and 5^th–6^th PAP rows, AAP setting in two rows on each interspace; AAP almost same size as PAP, which is more sizable than punctations in other species, with punctation diameter greater than interspace between 2^nd–3^rd PAP rows; both PAP and AAP beginning to decrease in size postmedially to apical third, and completely vanished at apical fifth; elytral inner surface with a wedge-shaped protuberance at lateral middle; tibiae spur formula 0–2–2 (other species in this genus 1–2–2); protibia with a blunt tooth at outer apex; 1^st–2^nd abdominal ventrites dark brown, 3^rd–5^th yellow, 6^th light yellow to transparent; first abdominal ventrite strongly ridged behind coxae, intercoxal process raised, triangular, slightly longer than broad, grooved longitudinally.

Malaysia (Peninsular Malaysia, Sabah).

India: “Inde Anglaise, Pedong, Région de Darjeeling. Chasseures indigènes, 1933 /Museum Paris, 1952, Coll. R. Oberthür / Gastrocentrum magnum sp. nov. males, Det. Yang G. Y. 2019 / Holotype: Gastrocentrum magnum sp. nov. Yang & Yang, 2020” (MNHN, male) (Fig. 1). Paratypes. India: “Assam / Museum Paris ex Coll. R. Oberthur” (MNHN, 1 male); “Assam, […] / Gastrocentrum dux Westw. / Museum Paris ex Coll. R. Oberthur / Ex-Musaeo H. W. Bates, 1892 / Museum Paris / females” (MNHN, 1 female); “Sikkim, Guntok, Eté 1894, Chasseurs Bretandeau / Gastrocentrum dux Westw. c.f. Gahan / Museum Paris ex Coll. R. Oberthur” (MNHN, 1 female). China: China, Xizang, Mêdog, Nyingchi, Baibung, 876 m, 2016.VIII.09, light trap, LU Yanquan leg. (CCCC, 1 female); Yunnan, Longchuan, 1770 m, 2016.VI.3, light trap, YANG Xiaodong leg. 16Y (CCCC, 1 female); “Hainan, Jianfengling, Tianchi, 2010.IV.15-20/Wenxin Lin, 950 m, Collection of CHEN Changchin” (CCCC, 1 female); China, Yunnan, Honghe, Lvshuihe, 640 m, 23°1'41"N, 103°24'19"E, 07.V.2019, leg. L.Z. Meng (NKME, 3 ex., RGCM,1 ex.); China, Yunnan, Honghe, Gulinqin, 585 m, 22°43'51"N, 103°59'35"E, 07.V.2019, leg. L.Z. Meng (RGCM, 2 ex.); China, S-Yunnan, Xishuangbanna, 20 km NW Jinghong, Man Dian NNNR-office, 22°07.80N, 100°40.05E, 740 m, LFF, 24.V.2008, leg. A. Weigel (RGCM, 1 ex.). Vietnam: C-Vietnam, ThuaThien – Hue Pr., Phu Loc, Bach Ma NP, Top area, 1250–1400 m, 16°11'39"N, 107°51'12"E, 5–9.V.2019, leg. A. Weigel LFF (RGCM, 1 ex.). Thailand: 18.–23.4.1991, Dol Suthep Pui, 1300–1500 m, leg. P. Pacholatko (RGCM, 1 male).

Earlier researchers identified one of the paratypes of this new species as G. dux. The new species can be separated from G. dux by: asetiferous punctations on elytra continuing to the tip (Fig. 10A); intercoxal process of first abdominal ventrite grooved longitudinally (Fig. 20F); female pygidium with anterior margin notched in a shallow triangular shape (Fig. 14A), and lateral tails of spermathecal gland extremely long, ca. 2 × the length of ovipositor (Fig. 14C, spglt). Gastrocentrum unicolor is sympatric with the new species in India, but G. magnum can be separated from it by much larger body size and five expanded terminal antennomeres (Fig. 13H).

Figure 13. 

Gastrocentrum magnum sp. nov. Holotype. A tegmen in lateral view a apex of tegmen in lateral view B tegmen in ventral view C phallus in lateral view D phallus in ventral view E spicular fork F pygidium G sixth ventrite H right antenna lacking last three segments. Scale bar: 1 mm.

General appearance: length 22–25 mm, robust, dark brown. Head: including eyes feebly broader than pronotum; eyes moderately large, distance between eyes slightly greater than the transverse diameter of eye; gular suture convergent in anterior; antennae expanded laterally from 7^th antennomere onwards (Fig. 13H); vertex and frons with dense punctations, with a very faint ridge along the midline, postgenae rugose. Pronotum: oblong, length/width ratio ca. 1.5, constricted posteriorly; surface finely and densely punctate, faintly rugose, clothed with long, yellow hairs. Elytra: oblong, sides subparallel, length/width ratio ca. 2.4, vested with dense golden setae; wedge-shaped protuberance present on inner surface; asetiferous punctations rows somewhat irregular, PAP in ten rows, AAP on interspaces between 1^st–2^nd, 3^rd–4^th, and 5^th–6^th PAP rows; AAP present in two incomplete rows, with longitudinal spacing between neighboring punctations uneven; AAP faintly smaller than or as big as PAP, interspace between 2^nd–3^rd PAP rows larger than punctation diameter (Fig. 10A); both PAP and AAP beginning to decrease in size postmedially and continuing to the tip, which are quite irregular near apical 1/5 of elytra (Fig. 10A). Legs: outer apex of protibia not extending outwards. Abdomen: intercoxal process of the first ventrite grooved longitudinally. Male genitalia: pygidium subquadrate, posterior margin rounded (Fig. 13F); sixth ventrite arciform, 3 × wider than length, posterior margin well rounded, central membranous region inverted trapezoidal, extending from anterior margin to posterior margin (Fig. 13G); tegmen tubiform, length ratio of phallobasic apodeme to phallobase ca. 1: 3.7 (Fig. 13A, B); parameres hooked (Fig. 13A, a); interphallic plate shorter than half length of phallus (Fig. 13D); phallus apex knot-like, faintly longer than broad (Fig. 13C, D). Female reproductive organs: pygidium slightly wider than length, posterior margin rounded (Fig. 14A); sixth ventrite trapezoidal, 3 × wider than long, posterior margin truncated, central membranous region broad, apical accessory membranous region petty (Fig. 14B); bursa copulatrix clearly defined; spermathecal gland with a short top tail (Fig. 14C, spgtt) and an extremely long lateral tail, which longer than twice length of ovipositor (Fig. 14C, spglt); spermatheca curved tubiform (Fig. 14C, sp).

Figure 14. 

A–C Gastrocentrum magnum sp. nov. female, paratype from Assam A pygidium B sixth ventrite C female reproductive organ D Gastrocentrum dux from Australia, female reproductive organ. Abbreviations: ali alimentary canal bc bursa copulatrix cov common oviduct olb oblique bacculi ovp ovipositor sp spermatheca spg spermathecal gland spgtt top tail of spermathecal gland spglt lateral tail of spermathecal gland va vagina vtb ventral bacculi. Scale bar: 1 mm.

The female paratype collected from Hainan has the spermatheca faintly bifurcated distally. This individual variation was also observed in specimens of G. zayuense collected from the same locality (Fig. 18D–J).

India (Assam, Sikkim), China (Xizang, Yunnan, Hainan), Vietnam, Thailand.

This new species, together with G. dux, have the largest body size in this genus. The specific epithet comes from the Latin adjective magnus (=large).

Australia: “Tillus dux / australie / Museum Paris, Coll. A. Sicard 1930 / Gastrocentrum dux (Westwood, 1852), Det. Yang G. Y. 2013” (MNHN, 1 female, dissected; Fig. 2).

The specimen examined can be separated with G. magnum by elytral asetiferous punctations stop by apical fifth, not continuing to the tip (Fig. 10B), intercoxal process of first abdominal ventrite not grooved, female pygidium with a semi-circle membranous region proximally, reaching half length of pygidium, lateral tail of spermathecal gland much shorter, only slightly longer than spermatheca (Fig. 14D, spglt).

General appearance: length 23–29 mm, robust, dark brown. Head: including eyes feebly broader than pronotum; eyes moderately large, distance between eyes nearly as long as the transverse diameter of eye; gular suture slightly convergent in anterior; antennae expanded laterally from 7^th antennomere onwards; vertex and frons densely punctate, with a very faint ridge along midline, postgenae rugose. Pronotum: oblong, length/width ratio ca. 1.4, constricted posteriorly; surface finely and densely punctate, clothed with light yellow hairs. Elytra: oblong, sides subparallel, length/width ratio ca. 2.31, vested with light yellow setae; wedge-shaped protuberance present on inner surface; PAP in ten rows, AAP on interspaces between 1^st–2^nd, 3^rd–4^th, and 5^th–6^th PAP rows; AAP present in two very incomplete rows, number of AAP less than that in G. magnum; AAP faintly smaller than PAP; interspace between 2^nd–3^rd PAP rows greater than punctation diameter; elytral punctations decreasing in size postmedially, and completely vanished at apical fifth (Fig. 10B). Legs: outer apex of protibia very faintly extending outwards, not forming a distinct tooth. Abdomen: intercoxal process of the first ventrite flat, not grooved. Male genitalia: not studied. Female reproductive organs: pygidium slightly wider than long, posterior margin rounded, a semi-circle membranous region present proximally, reaching to half length of the pygidium; sixth ventrite trapezoidal, wider than long; bursa copulatrix clearly defined; spermathecal gland only with one lateral tail, which slightly longer than spermatheca in fully stretched condition (Fig. 14D, spglt); spermatheca boot-shaped (Fig. 14D, sp).

Mawdsley (1999) claimed that the type specimen of G. dux was deposited in the Hope Department of Entomology, University Museum, Oxford, United Kingdom, but it was not located during a visit to that museum in 2011 by the first author. Westwood (1852) indicated that the type specimen was from “Mus. Melly”, but efforts to locate it in Melly’s collection in the Natural History Museum, Geneva, yielded no results either. The whereabouts of the type specimen remains unknown.

The Australian type locality of this species is doubted by the Australian entomologist and clerid worker Justin Bartlett who, after viewing the Cleridae holdings of all major museum, and several agricultural and private collections from all Australian states, is yet to find a single Gastrocentrum specimen, and therefore does not believe G. dux to be an Australian species. He also doubts that the locality label of the specimen examined in this manuscript represents an actual collecting event, but rather was labelled after it was identified as G. dux, with the associated type locality of ‘Australie’ (pers. comm. J Bartlett). He also pointed out that another apparently Australian specimen from Melly’s collection, a longicorn Hephaestion acraetus Newman, is in fact a Chilean species (see Saunders 1850), providing a precedent for erroneously labelled specimens from Melly’s collection. Despite this, no more practical specimen-based evidence for or against this argument has been found. Hence, we can only describe this species based on the specimen mentioned above at the moment, as we can only take the label at face value and assume it to represent an actual collecting label.

We found a Tenebrionidae beetle with the same Swan River type locality also originating from Melly’s collection and described by Westwood: Prophanes aculeatus Westwood, 1849. It is presently treated as a valid species, with an eastern, not western, Australian distribution (Westwood 1849; Carter 1913; Matthews 1992). Gastrocentrum dux may have a similar historical story and its correct occurrence could be in other areas of Australia or in other regions of the world, but this hypothesis needs to be proved by further specimens.

Malaysia: “Malaysia, Pahang, Cameron Highlands, Tanah Rata vill. env., Gunung Jasar [Mt.]; 1470-1705m, 04°28.4–7'N, 101°21.6–22.1'E, Jiří Hájek leg. 18.iv–10.v.2009 / Holotype: Gastrocentrum regulare sp. nov. Yang & Yang, 2020” (NMPC, male, Fig. 4); Paratype. Same data as holotype (NMPC, 1 female).

This species is distinct in the genus in having ten regular rows of asetiferous punctations exceeding half of elytra, without AAP between the PAP rows. It can be differentiated from G. xiaodongi by: antennae expanded laterally from 7^th antennomere onwards (Fig. 15I); elytra punctations rows stop by apical third (Fig. 10C); inner surface of elytron with a wedge-shaped protuberance; intercoxal process of first abdominal ventrite grooved longitudinally; spermathecal capsule slenderer, tapering to the tip (Fig. 16A, sp).

General appearance: length 12–14 mm, robust, dark brown. Head: including eyes feebly broader than pronotum; eyes moderately large, distance between eyes almost as long as the transverse diameter of eye; gular suture almost straight-up; antennae expanded laterally from 7^th antennomere onwards (Fig. 15I); vertex and frons roughly punctate, postgenae rugose. Pronotum: oblong, length-width ratio ca. 1.5, constricted posteriorly; surface finely and densely punctate, clothed with long, yellow hairs. Elytra: oblong, sides subparallel, length/width ratio ca. 2.6, vested with grayish white setae; wedge-shaped protuberance present on inner surface; PAP arranged in ten rows, AAP absent; interspace between 2^nd–3^rd PAP rows ca. 2 × as wide as the punctation diameter; asetiferous punctations decreasing in size postmedially, and completely vanished at apical third (Fig. 10C). Legs: outer apex of protibial apex slightly extending obliquely, not forming a distinct tooth. Abdomen: intercoxal process of the first ventrite grooved longitudinally; metacoxal abdominal depressions weekly ridged in anterior margin, perpendicular carinae absent. Male genitalia: pygidium subquadrate, posterior margin rounded (Fig. 15G); sixth ventrite arciform, 3 × wider than length, posterior margin rounded, central membranous region oval, extending from anterior margin to posterior margin (Fig. 15H); tegmen tubiform, length ratio of phallobasic apodeme to phallobase ca. 1: 2.1 (Fig. 15A–C); parameres expanded, unhooked (Fig. 15B, b); interphallic plate shorter than half length of phallus (Fig. 15E); phallus apex knot-like, rounded (Fig. 15D, E). Female reproductive organs: pygidium slightly wider than long, posterior margin rounded (Fig. 16B); sixth ventrite trapezoidal, 3 × wider than long, central membranous region broad, apical accessory membranous region absent (Fig. 16C); bursa copulatrix clearly defined; spermathecal gland with a top tail of medium length (Fig. 16A, spg); spermathecal duct slender; spermathecal capsule slender, tapering to the tip, length/width ratio = 3.6 (Fig. 16A, sp).

Figure 15. 

Gastrocentrum regulare sp. nov. male Holotype. A aedeagus in ventral view B tegmen in lateral view b apex of tegmen in lateral view C tegmen in ventral view D phallus with connecting membrane inverted, lateral view E phallus with connecting membrane inverted, ventral view F spicular fork G pygidium H sixth ventrite I antenna. Scale bar: 1 mm.

Malaysia (Peninsular Malaysia).

Refer to the highly regular elytral asetiferous punctations of this species.

Figure 16. 

A–C Gastrocentrum regulare sp. nov. female paratype A female reproductive organ B pygidium C sixth ventrite D–H Gastrocentrum xiaodongi sp. nov. female holotype D pygidium E sixth ventrite F, G female reproductive organ H antenna. Abbreviations: bc bursa copulatrix cov common oviduct ovp ovipositor pgb proctigeral bacculi sp spermatheca spg spermathecal gland spgtt top tail of spermathecal gland va vagina v6 sixth ventrite. Scale bars: 0.5mm (A–F, H).

China: “Xizang (Tibet), Jilongxian [Gyirong county], 1785m, Xinjiangcun, 2019.VI.28, leg. X-D. YANG / Holotype: Gastrocentrum xiaodongi sp. nov. Yang & Yang, 2020” (CCCC, female, Fig. 5). Paratypes. Nepal: Manaslu Mts., E slope of Ngadi Khola valley, 2000–2300 m, 14–16.V.2005, leg. J. Schmidt, 28°22'N, 84°29'E (RGCM, 1 male); W-Nepal, Modi Khola, Bhakta B.; Banthanti – 2500 – Landrung – 1600 m, 2.VI.1984 (NHMB, 1 female).

This new species is different from G. regulare sp. nov. by: antennae expanded laterally from 8^th antennomere onwards; elytral asetiferous punctations stop by middle (Fig. 10D); elytral inner surface without wedge-shaped protuberance; intercoxal process of first abdominal ventrite not grooved (Fig. 20C, ip); spermathecal capsule thicker, rounded distally (Fig. 16F, sp). The new species also looks similar to G. zayuense sp. nov. and G. gaoligongense sp. nov. at first glance, but it differs from the latter two species by: elytral asetiferous punctations somewhat larger and reaching lateral margins (Fig. 10D), female antennae expanded laterally from 8^th antennomere onwards (Fig. 16H). It also differs from G. gaoligongense sp. nov. by elytral inner surface without a wedge-shaped protuberance.

General appearance: length 14 mm, brown, a little slenderer than previous species. Head: including eyes slightly broader than pronotum; eyes moderately large, distance between eyes slightly greater than the transverse diameter of eye; female antennae expanded laterally from 8^th antennomere onwards (Fig. 16H); vertex and frons rugose, densely punctate, postgenae rugose. Pronotum: oblong, length/width ratio ca. 1.6, constricted posteriorly; surface finely and densely punctate, clothed with long, yellow hairs. Elytra: oblong, sides subparallel in basal half and weekly widened in apical half, length/width ratio ca. 2.4, vested with yellow setae; wedge-shaped protuberance absent on inner surface; PAP only present on basal half in ten rows, AAP absent, PAP a little larger than those in G. regulare, G. zayuense, and G. gaoligongense; interspace between 2^nd-3^rd PAP rows greater than punctation diameter (Fig. 10D). Legs: outer apex of protibia not extending outwards. Abdomen: intercoxal process of the first ventrite not grooved longitudinally; metacoxal abdominal depressions weekly ridged in anterior margin, perpendicular carinae absent. Male genitalia: not studied. Female reproductive organs: pygidium slightly broader than long, posterior margin rounded (Fig. 16D); sixth ventrite semi-circle, central membranous region broad, apical accessory membranous region absent (Fig. 16E); both dorsal and ventral lamina have three incisions; bursa copulatrix clearly defined; spermathecal gland with a short top tail; spermathecal duct slightly inflated distally; spermathecal capsule rounded in apex, length/width ratio = 2.0. (Fig. 16F, G).

China (Xizang, Gyirong), Nepal.

We are pleased to dedicate this species to its collector and our friend, Mr Yang Xiaodong.

China: Xizang Autonomous Region, Nyingchi prefecture, Zayü County, Zhowagoin, 2011.VII.1, BI Wenxuan leg, 2500 m / Holotype: Gastrocentrum zayuense sp. nov. Yang & Yang, 2020 (CBWX, male, Fig. 6); Paratypes. same as holotype (CBWX, 15 ex.); same as holotype but collected by LIU Ye on 2011.VII.3 (IZAS, 9 ex.); same but collected by Yang Xiaodong on 2011.VII.3 (CCCC, 1 ex.).

This species differs from G. gaoligongense sp. nov. by elytral inner surface without wedge-shaped protuberance; tegmen apices with ventral surface streamlined in lateral view (Fig. 17a), female bursa copulatrix clearly defined, much narrower than vagina, distal part of spermathecal capsule short, length/width ratio < 2.5 (Fig. 18A).

Figure 17. 

Gastrocentrum zayuense sp. nov. Holotype male. A tegmen in lateral view a apex of tegmen in lateral view B tegmen in ventral view C phallus in lateral view D phallus in ventral view E spicular fork F pygidium G sixth ventrite H antenna. Scale bar: 1mm.

General appearance: length 13–18 mm, somewhat slenderer than G. regulare, light brown. Head: including eyes feebly broader than pronotum; eyes moderately large, distance between eyes slightly greater than the transverse diameter of eye; gular suture slightly convergent in anterior; female antennae broadly expanded laterally from 7^th antennomere onwards, while male 7^th antennomere less expanded (Fig. 17H); vertex and frons finely punctate, postgenae rugose. Pronotum: oblong, length/width ratio ca. 1.5, constricted posteriorly; surface finely and densely punctate, clothed with long, yellow hairs. Elytra: oblong, sides subparallel in basal half and a little widened in apical half, length/width ratio ca. 2.5, vested with light yellow setae; wedge-shaped protuberance absent on inner surface; elytron smooth without asetiferous punctations or with very few asetiferous punctations, number of PAP ranged from 0~27 (n = 26), present on elytral basal disc in six rows in maximum, AAP absent (Fig. 10F–H). Legs: outer apex of protibia not extending outwards. Abdomen: intercoxal process of the first ventrite not grooved longitudinally (Fig. 20C); metacoxal abdominal depressions weekly ridged in anterior margin, perpendicular carinae absent. Male genitalia: pygidium with posterior margin rounded (Fig. 17F); sixth ventrite arciform, width twice length, posterior margin rounded, central membranous region small, rhombic, extending from anterior margin to half-length of the ventrite (Fig. 17G); tegmen tubiform, length ratio of phallobasic apodeme to phallobase ca. 1: 3.2 (Fig. 17A, B); parameres hooked, ventral surface of the hook streamlined in lateral view (Fig. 17a); interphallic plate shorter than half length of phallus (Fig. 17D); phallus apex knot-like, approximately as long as wide (Fig. 17C, D). Female reproductive organs: pygidium subquadrate, posterior margin rounded (Fig. 18B); sixth ventrite trapezoidal, twice as broad as long, rounded posteriorly, central membranous region broad and extending posteriorly at sides, apical accessory membranous region absent (Fig. 18C); bursa copulatrix clearly defined; spermathecal gland with a top tail of medium length; spermathecal duct inflated distally where continuous with spermathecal capsule; spermathecal capsule simple or feebly bifurcate (Fig. 18D–J), distal part of spermathecal capsule short, length/width ratio < 2.5 (Fig. 18A, E–J).

Figure 18. 

Gastrocentrum zayuense sp. nov. paratypes, female reproductive organs of different specimens showing morphological variations. A female reproductive organ B pygidium C sixth ventrite D spermatheca E–J drawings of bursa copulatrix, spermatheca and spermathecal gland of six females. Abbreviations: bc bursa copulatrix cov common oviduct d distal part of spermathecal capsule ovp ovipositor sp spermatheca spg spermathecal gland spgtt top tail of spermathecal gland spglt lateral tail of spermathecal gland va vagina.

All examined specimens are from exactly same locality, they vary individually in the number of punctations on one elytron from zero to 27, and spermatheca apex being simple or feebly bifurcate distally.

China (Xizang, Zayü).

Habitat is shown in Fig. 24. The specimens were collected on the tree trunk at night.

The new species is named after its type locality.

China: “CHINA, Yunnan Province, Fugong Co., Lishadi town, Shibali village, roadside, 27.16520°N, 98.77980°E / 2530 m, 2004.5.5, night, Liang H-B, Li X-Y, coll., California Academy &IOZ., Chinese Acad Sci / IOZ(E) 1890507 / Holotype / Gastrocentrum gaoligongense sp. nov. Det. Yang G.Y. 2020” (IZAS, male) (Fig. 7). Paratypes. CHINA: Yunnan, Gongshan, Menggaguo, 2800 m, Light, 2016.VII.8, Yu-Tang Wang leg. (CCCC, 1 male, 1 female); same but 2016.VI.30 (CCCC, 1 male); same but 2016.VI.24 (CCCC, 1 female).

The new species differs from G. zayuense sp. nov. by: elytra with a pair of wedge-shaped protuberance on inner surface; tegmen apices bulged on ventral surface (Fig. 19b); female bursa copulatrix not differentiated, merely a swollen continuation of the vagina, distal part of spermathecal capsule, long and slender, length/width ratio > 5 (Fig. 22E).

Figure 19. 

Gastrocentrum gaoligongense sp. nov. Holotype male. A aedeagus in ventral view B. tegmen in lateral view b apex of tegmen in lateral view C tegmen in ventral view D phallus in ventral view d apex of phallus E spicular fork F pygidium G sixth ventrite H antenna. Scale bars: 1mm.

General appearance: length 13–19 mm, slenderer than all the other species, dark brown. Head: including eyes slightly broader than pronotum; eyes moderately large, distance between eyes slightly longer than the transverse diameter of eye; gular suture slightly convergent in anterior; female antennae broadly expanded laterally from 7^th antennomere onwards, while male 7^th antennomere less expanded (Fig. 19H); vertex and frons with dense and somewhat coarse punctations, postgenae rugose. Pronotum: oblong, length/width ratio ca. 1.6, constricted posteriorly, faintly constricted anteriorly; surface finely and densely punctate, clothed with long, yellow hairs. Elytra: oblong, sides subparallel in basal half and weekly widened in apical half, length/width ratio ca. 2.6, vested with light yellow setae; wedge-shaped protuberance present on inner surface; elytra with very few asetiferous punctations, number of PAP on each elytron ranged from 2~39 (n = 5), present on elytral basal disc in five rows in maximum, AAP absent (Fig. 10E). Legs: outer apex of protibia not extending outwards. Abdomen: intercoxal process of the first ventrite not grooved longitudinally; metacoxal abdominal depressions weekly ridged in anterior margin. Male genitalia: pygidium with posterior margin rounded (Fig. 19F); sixth ventrite arciform, width twice length, posterior margin rounded, central membranous region small, extending from the anterior margin, not reaching half-length of ventrite (Fig. 19G); tegmen tubiform, length ratio of phallobasic apodeme to phallobase ca. 1: 3.2 (Fig. 19A–C); parameres hooked, ventral surface of the hook bulged in lateral view (Fig. 19b); interphallic plate shorter than half length of phallus (Fig. 19D); phallus apex knot-like, slightly longer than wide (Fig. 19D, d). Female reproductive organs: pygidium slightly broader than long, posterior margin rounded; sixth ventrite widely trapezoidal, 2.5 × broader than long, rounded posteriorly, central membranous region broad, apical accessory membranous region absent; bursa copulatrix unclearly defined, merely swollen continuation of vagina; spermathecal gland with a top tail of medium length; spermathecal duct long and slender; spermathecal capsule feebly bifurcate in sub-apex; distal part of spermathecal capsule long and slender, length/width ratio > 5 (Fig. 22E).

Figures 20–21. 

20A, B wedge-shaped protuberance on inner surface of elytron with G. unicolor as an example C, D abdomen of G. zayuense in ventral and lateral view showing 1^st–5^th ventrites with short lateral ridges on each segments E intercoxal process of first ventrite of G. unicolor showing the longitudinal groove F claws of Isocymatodera atricolor. 21 Female reproductive organs of G. zayuense sp. nov. not stained and with the dark background, revealing the internal tissues. Abbreviations: bc bursa copulatrix ip intercoxal process mt microtrichia field pig less pigmented circles on abdominal segments ridge short ridges on abdominal segments spc spermathecal capsule spd spermathecal duct spg spermathecal gland spgd spermathecal gland duct va vagina. Scale bars: 0.5 mm (20A–D) 1 mm (21).

China (Yunnan).

The holotype and paratypes of this new species were collected from two sites of the Gaoligong Mountains in Yunnan Province, China. The specific name is an adjective that refers to this mountain.

This species was not studied because specimens were unavailable. Gerstmeier (2005) stated that the position of this species in the genus Gastrocentrum is doubtful because its pronotum was not elongated, but rather spherical.

“Banshoryo Distr. Sokutsu (Formosa), H. Sauter VII. 1912 / Holotypus / Schenkling det. / Gastrocentrum nitidum Schklg. Typus!” (SDEI, female; Fig. 8).

This species is transferred to the genus Tillus for its claw with two inner denticles (basal denticle trigonal). This type of claw was imaged in Burke (2017: 179, fig. B) of the species Cymatodera balteata.

“[...] / voi Tillus / Type [printed] Strotocera atricolor nouv. [hw. by Pic] / ?abyssinie / voi Strotocera / type [hw. by Pic] / Paris” (MNHN, 1 female; Fig. 9); “Baria / Baria (Cochinchina) / acq. 1930 coll. Ch. Madon (Le Moult) / Cotype: Strotocera atricolor Pic, 1934 / Strotocera atricolor Pic, 1935, ZMAN type 1939.1” (ZMAN, 1 female).

China. Hainan, Changjiang County, Bawangling Forest Nature Reserve (IZAS, 6 ex.); Ledong County, Jianfengling Tropical Rainforest National Park (IZAS, 4 ex.); Baisha County (IZAS, 1 ex.). Vietnam. “Baria [...]/Baria (Cochinchina) / acq. 1930 coll. Ch. Madon (Le Moult) / Homotype: (Corporaal comp.): Strotocera atricolor Pic” (ZMAN, 1 ex.).

This species is recorded from China for the first time, and hence we provide a short note here.