Gastrocentrum Gorham, 1876

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

publication ID	https://dx.doi.org/10.3897/zookeys.979.53765
publication LSID	lsid:zoobank.org:pub:BC56F2AE-D8F9-411E-9C92-81945738E264
persistent identifier	https://treatment.plazi.org/id/451565E1-1D67-5B60-ABF4-55DB333AD2AB
treatment provided by	ZooKeys by Pensoft
scientific name	Gastrocentrum Gorham, 1876
status

Treatment

Genus Gastrocentrum Gorham, 1876

Gastrocentrum Gorham, 1876: 63 (Type species: Gastrocentrum pauper Gorham, 1876; by original designation); Chapin, 1924: 166, 179 (redescription).

Exocentrum Pic, 1940: 3 (printer error).

Diagnosis.

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 View Figures 20–21 ). The genus Gastrocentrum can be differentiated from Isocymatodera by antennae broadly expanded laterally from 7th or 8th 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 3rd or 4th antennomeres onwards, the connecting membrane of male aedeagus is only specialized in dorsal surface, and the female vagina possesses sclerites.

Redescription.

General appearance: body length 9-29 mm; oblong, somewhat robust; all the species except G. laterimaculatum uniformly dark brown (Figs 1-9 View Figures 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 7th or 8th-11th, 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 View Figures 20–21 ), 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 View Figures 20–21 , 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 View Figure 10 ), sometimes PAP vanish in lateral elytron (in G. zayuense and G. gaoligongense , Fig. 10E-H View Figure 10 ); AAP may present on the interspaces between 1st-2nd, 3rd-4th, and 5th-6thPAP rows and similar with PAP in size, making these two types of punctations more or less indistinguishable (Fig. 10A, B View Figure 10 ); 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 View Figures 20–21 ). 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 View Figures 20–21 ) and a pair of less pigmented circles (Fig. 20C View Figures 20–21 ) 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 View Figure 11 , 13G View Figure 13 , 15H View Figure 15 , 17G View Figure 17 , 19G View Figure 19 ); 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 View Figure 11 , 13E View Figure 13 , 15F View Figure 15 , 17E View Figure 17 , 19E View Figure 19 ); 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 View Figure 15 ); 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 View Figure 11 , 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 View Figure 11 ). Female reproductive organs: pygidium subquadrate; sixth ventrite sub-triangular, disc membranous (Figs 12H View Figure 12 , 14B View Figure 14 , 16C, E View Figure 16 , 18C View Figure 18 ), spiculum ventrale present; ovipositor as long as abdomen, moderately sclerotized, light yellow, semi-transparent (Figs 12F View Figure 12 , 14C, D View Figure 14 , 16A, F View Figure 16 , 18A View Figure 18 , ovp), with proctigeral bacculi in dorsal surface (Fig. 16F View Figure 16 , pgb) and ventral and oblique bacculi in ventral surface (Fig. 14C View Figure 14 , 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 View Figure 12 , 16A View Figure 16 , 18A View Figure 18 , bc) with the exception of the species G. gaoligongense , where bursa copulatrix is a mere swollen continuation of the vagina (Fig. 22E View Figure 22 ); spermatheca attached to the base of bursa copulatrix, boundary between spermathecal duct and spermathecal capsule somewhat obscure (Figs 16G View Figure 16 , 21 View Figures 20–21 ), spermathecal duct slender (Fig. 16A View Figure 16 ) or sometimes inflated in distal and continuous with spermatheca (Figs 16G View Figure 16 , 18A View Figure 18 ), 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 View Figure 16 ), spermathecal gland duct inserted at the outer edge of the angle (Fig. 21 View Figures 20–21 , spgd); in ground-plan, spermathecal gland have three tail-like endings: one located distally, opposite to its opening to spermatheca (top tail, Figs 12E View Figure 12 , 14C View Figure 14 , spgtt), the other two situated laterally (lateral tail, Figs 12E View Figure 12 , 14C View Figure 14 , spglt), any of which may be missing in different species and sometimes can be extremely long (Fig. 14C View Figure 14 , spglt).

Distribution.

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 View Figure 25 ).