Gastrocentrum magnum sp. nov.

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 magnum sp. nov. Figures 1 , 10A , 13 , 14 , 25

Holotype.

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).

Diagnosis.

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 ).

Description.

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 7th 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 1st-2nd, 3rd-4th, and 5th-6thPAP 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 2nd-3rdPAP 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).

Variation.

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 ).

Distribution.

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

Etymology.

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).

Figures

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.

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.

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.

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.

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).