Gastrocentrum unicolor (White, 1849)

Yang, Ganyan, Yang, Xingke & Shi, Hongliang, 2020, Taxonomy and phylogeny of the genus Gastrocentrum Gorham (Coleoptera, Cleridae, Tillinae), with the description of five new species, ZooKeys 979, pp. 99-132 : 99

Gastrocentrum unicolor (White, 1849) Figures 3 , 11 , 12 , 25

Notoxus unicolor White, 1849: 56 (type locality: “India”); Gahan, 1910: 61 ( Gastrocentrum ); Schenkling, 1912: 323 (Taiwan); Chapin, 1924: 179, pl. 1, f. 4 (Philippines); Corporaal, 1950: 55 (catalogue); Mawdsley, 1999: 270 (Sri Lanka).

Gastrocentrum pauper Gorham, 1876: 63 (type locality: "Luzon, Philippines"); Schenkling, 1903 (Dindigul, S. India); Gahan, 1910: 61 (synonymized with G. unicolor White).

Type specimens examined.

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).

Other specimens examined.

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).

Diagnosis.

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 8th 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 1st-2nd, 3rd-4th, and 5th-6thPAP rows.

Redescription

(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 8th 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 1st-2nd, 3rd-4th, and 5th-6thPAP rows, AAP setting in two rows on each interspace; AAP almost same size as PAP; interspace between 2nd-3rdPAP 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 ).

Variation.

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 .

Distribution.

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).

Discussion.

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.

Figures

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.

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.

Figure 25. Geographical distribution map of the genus Gastrocentrum.

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: 5 mm (1, 2) 2 mm (3 - 9).

Figures 20 - 21. 20 A, 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 (20 A-D) 1 mm (21).