Review of the species of Leptomias Faust from Sichuan, China (Coleoptera, Curculionidae, Entiminae)

Abstract An account is given of the twelve species of Leptomias Faust, 1886 occurring in the Sichuan Province of China, including the description of a new species, Leptomias verticalis Ren, Zhang & Song, sp. n. from Jiulong County, Southwest Sichuan. New locality data and remarks for the other eleven species, a key to and distribution map of all twelve Sichuan species are provided. Leptomias chenae Alonso-Zarazaga & Ren is transferred to Geotragus Schoenherr, 1845, where its valid name is G. granulatus (Chao, 1980), comb. n. in application of Art. 59.4. Structural details of Leptomias verticalis and Geotragus granulatus are illustrated.


Introduction
Leptomias Faust, 1886 is a diverse genus of flightless weevils (Coleoptera, Curculionidae) in the subfamily Entiminae, with a centre of distribution in China, India, Nepal, Afghanistan and Myanmar. It differs from related genera by having (i) the metanepisternum completely separated from the metaventrite and (ii) the upper edge of the scrobes directed towards the lower margin of the eye (Chao 1980). Ninety per cent of the Leptomias species known from China occur in Xizang, Yunnan, Sichuan and Qinghai. During identification of specimens collected in Sichuan province, one new and one misplaced species were found. Leptomias chenae  (renamed because of secondary homonymy of its original name, Leptomias granulatus Chao, 1980) does not belong in Leptomias but instead to the genus Geotragus Schoenherr, 1845. With the transfer of this species out of Leptomias effected and the new species described in this paper, the number of current species of Leptomias remains at 159 and that of species recorded from China at 89. The new species and the new combination are here documented and illustrated, along with a key to the species present in Sichuan. Moreover, species documented in Sichuan are usually described in Chinese and it might be difficult for most people to obtain information of their distribution.

Material and methods
All specimens, including types, examined for this study are located in the following collections: Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZCAS); Forschungsmuseum Alexander Koenig, Bonn, Germany; Natural History Museum, London, UK; Naturkundemuseum, Berlin, Germany; Senckenberg Naturforschendes Museum, Frankfurt am Main, Germany; Senckenberg Naturhistorische Sammlungen, Dresden, Germany. The types of the new species are deposited in IZCAS.
Specimens were dissected after soaking them in soapy water overnight, for cleaning and softening, and the dissected parts were placed in a cold 10 % NaOH solution for 20 hours to macerate the soft tissues. After dissection, all parts were photographed and stored in glycerine in microvials pinned beneath the specimen from which they were dissected.
The morphological terminology used in this study mainly follows . Measurements were made using an ocular micrometre as follows: standard length -in dorsal view from anterior margin of thorax to apex of elytra along midline; pronotal length -in dorsal view from anterior margin to base along midline; pronotal widthin dorsal view across widest part; elytral length -in dorsal view along suture of elytra from base to apex; elytral width -in dorsal view across widest part; rostral length -in lateral view in a straight line from apex to anterior margin of eye; rostral width -in dorsal view across base of rostrum. Measurements are made in millimetres.
All observations and dissections were performed using a Nikon SMZ1500 stereo microscope. The habitus photographs were taken with a MP-E 65 macro lens mounted on a CANON EOS700D digital camera. Other photographs were taken with a CCD Qimagine MicroPublisher 5.0 RTV camera mounted on a Zeiss SteREO Discovery V.12 microscope. Extended-focus images were generated with Auto-Montage Pro 5.03.0061 and edited with Adobe Photoshop CS 14.0 if required.
Label data are given verbatim, with pinyin romanisation and comments in square brackets if labels are in Chinese; labels are separated by semicolons and lines by slashes. with the shortest desmomere 5), 3 and 4 equal in length, shortly clavate, 0.63× as long as 2, 5 elongate moniliform, 0.72× as long as 4, 6 1.17× longer than 5, shortly clavate, 7 as long as 3, shortly clavate; clubs with similar pubescence throughout, elongate-oval, 0.33× as long as desmomeres, 3-segmented, basal segment 1.33× longer than segment 2, this 0.89× as long as 3, 3 with a marked annulus at midpoint.
Pronotum: subquadratic in dorsal outline, strongly convex; anterior margin truncate, posterior margin medially slightly produced caudad; sides strongly rounded, greatest width at midpoint, gradually narrowing towards both ends, anterior margin slightly shorter than posterior one; disc smooth, median sulcus absent; posterior margin narrowly and slightly carinate; dorsal surface with dense, small and round tubercles, each tubercle with 1 scale on top; postocular lobes absent, vibrissae blond, moderately long.
Proventriculus (Fig. 17): Well developed, with eight sclerotized basal plates, each plate bearing two longitudinal rows of projecting setae, brush-like, apically ending with a trapezoidal zone covered with pointed inward denticles.
Elytra : In dorsal view elongate-ovate, anterior margin medially slightly produced and elevated as prominent flange, without humeral callus; lateral margins slightly diverging from base to basal 1/5, there widest apart, then evenly converging towards narrowly rounded apex; in lateral view with posterior declivity straight and not overhanging elytral apex; with ten complete, distinct, narrow, moderately deep, punctate striae; punctures minute, moderately dense, intervals between punctures narrow; interstriae wide, slightly eminent.
Abdomen (Fig. 10): Ventrite 1 depressed in middle, slightly convex at sides, in middle longer than 2, suture between 1 and 2 slightly curved forward in middle,; ventrite 2 moderately convex, as long as 3 and 4 combined; ventrite 5 as long as 1 in middle, moderately convex, broadly rounded at apex. Metendosternite ( Fig. 11): Stalk 0.39× as long as furcal arms, trapezoidal and transverse, anterior part of longitudinal flange slightly shorter than posterior part; hemiductus inconspicuous; anterior tendons positioned almost at apical 1/3 of furcal arms; furcal arms robust, apically not bifurcate, diverging at nearly 60°in relation to longitudinal flange.
Material examined. Remarks. The specific epithet refers to the straight declivity of the elytra in lateral view.

Remarks.
Leptomias elongitus is known from the province of Sichuan (Derong) and Xizang (Mangkang). It is narrowly distributed in the southwest of Sichuan (Fig. 24). Leptomias elongitus resembles L. nubilus but differs by the following characters: antennae with scape extending beyond anterior margin of eye but not reaching middle when at rest; postocular lobes developed; prothorax broadest behind middle.

Leptomias foveicollis Voss, 1935
Leptomias foveicollis Voss, 1935. Entomologisches Nachrichtenblatt 9(2): 58. Remarks. Leptomias foveicollis is widely distributed in Sichuan (Baoxing, Kangding, Ganzi, Lixian), Liaoning (Changtu) and Heilongjiang (Haerbing). From southwest to northeast of China, this species has a wide distribution range. Leptomias foveicollis is widely distributed in the central-western region of Sichuan (Fig. 24). This species is similar to L. moxiensis but can be differed from the following characters: prothorax strongly convex, broadest behind middle, with fovea on either side of median longitudinal groove; elytra every interstriae with 1-2 column setae; procoxae contiguous, inner sides flat; penis long and robust, apex elongate and obliquely truncate. We could not locate type materials, all above are based on identified specimens.

Remarks.
Leptomias moxiensis is also an endemic species of China. It is recorded only from Luding, the central region of Sichuan (Fig. 24). Leptomias moxiensis can be identified by the following characters: prothorax broadest in middle, pronotum corrugated, with very fine, deep median longitudinal groove; antennae with scape reaching posterior margin of eye when at rest; elytra every interstriae with one column setae; prementum with two setae; procoxae separated from each other, inner sides flat; metatibiae with mucro.

Leptomias nubilus Chen, 1983
Leptomias nubilus Chen, 1983. Acta Zootaxonomica Sinica 8(4): 397-398, fig. 2 Remarks. Leptomias nubilus is recorded from Sichuan (Xiangcheng) and Xizang (Mangkang). Xiangcheng is located in the southwest region of Sichuan (Fig. 24). Leptomias nubilus can be distinguished from L. elongitus by antennae with scape reaching middle of eye when at rest; eyes large and slightly flat; postocular lobes not developed; with a depression positioned laterally between the upper margin of antennal scrobe and the front of eyes; prothorax rather smooth, without median longitudinal, broadest before middle.

Leptomias ochrolineatus Chen, 1987
Leptomias ochrolineatus Chen, 1987. Acta Zootaxonomica Sinica 12(4): 406-407, fig. 4 Remarks. Leptomias ochrolineatus is endemic to China and collected only from Sichuan (Dege). It is narrowly distributed in the northwest region of Sichuan (Fig. 24). Leptomias sublongicollis and L. varians are also recorded from the same locality, Dege; however, L. ochrolineatus is very different from L. varians: elytra in lateral view moderately flat, intervals convex, with odd intervals more raised than even ones; prothorax broadest in middle; pronotum without median longitudinal groove; penis bent downwards at apex. L. ochrolineatus is similar to L. verticalis except the following characters: prementum with two setae; antennae with scape extending beyond middle of eye when at rest; elytra in lateral view with posterior declivity not straight; scutellum large, ligulate.

Leptomias varians Chen, 1987
Leptomias varians Chen, 1987. Acta Zootaxonomica Sinica, 12(4): 405, fig. 2 Remarks. Leptomias varians is an endemic species of China, collecting from Sichuan (Dege) (Fig. 24). L. varians, L. ochrolineatus and L. sublongicollis are all recorded from the same county. It is close to but can be differed from L. ochrolineatus by these characters: elytra in dorsal view broadly ovate; prothorax broadest behind middle, with very fine and shallow median longitudinal groove; elytral intervals flat; the metatibial apex with mucro; penis bent upwards at apex. Leptomias varians resembles L. sublongicollis, but can be identified by the following characters: elytra every interstriae with 1-2 column setae; scrobes with dorsal margin not carinate; postocular lobes developed; eyes large and slightly flat; penis not bent at apex.

Leptomias wenchuanensis Chen, 1992
Leptomias wenchuanensis . In Chen S (Ed) Insects of the Hengduan Mountains Region 2: 843, fig. 11. Remarks. Leptomias zheduoshanensis is another endemic species of China which recorded from Sichuan (Kangding). It is narrowly distributed in the central region of Sichuan (Fig. 24). Leptomias zheduoshanensis, L. foveicollis and L. thibetanus are all distributed in Kangding County. Leptomias zheduoshanensis differs from L. thibetanus by the following characters: prothorax broadest in middle; striae with small punctures; rostrum dorsal surface with a narrow and deep median sulcus, not reach the vertex; elytra every interstriae with one column setae; penis bent upwards at apex. A species-group name rejected after 1960 on grounds of secondary homonymy is to be reinstated as valid by an author who considers that the two speciesgroup taxa in question are not congeneric, unless it is invalid for some other reason." Redescription. Body medium-sized, black to reddish brown. Eyes lateral, oval, convex, with deep and fine circumferential stria. Rostrum 1.14× longer than wide, base narrower than frons, with slightly broad, deep median sulcus, reaching vertex. Scapes short and stout, exceeding anterior margin of eyes but not surpassing middle of eyes. Funicles with desmomere 1 elongate clavate, apical stout, 1.70× longer than desmomere 2, distinctly wider than 2. Prementum with four setae. Prothorax transverse, sides evenly rounded, broadest behind middle, pronotum with extremely shallow, fine, incomplete, median longitudinal groove. Elytral interstriae slightly elevated, unequal in width, without tubercles. Proventriculus (Fig. 30): well developed, with sclerotized basal plates, each plate brush-like, apically ending with a trapezoidal zone covered with pointed inward denticles. Metendosternite (Figs 36, 39): stalk 0.23× as long as furcal arms, anterior tendons positioned almost at apical 1/2 of furcal arms; furcal arms robust, apically not bifurcate, diverging at nearly 60°in relation to longitudinal flange. Male genitalia and terminalia: sternite VIII (Fig. 31) divided into two transversely orientated, crescent-shaped hemisternites; spiculum gastrale 0.26× as long as aedeagus, almost straight, strongly sclerotized; penis (Figs 32, 33) in dorsal view 3.36 mm long and 0.36 mm wide, aedeagal apodemes 0.69 mm long, lateral margins subparallel in middle; tegmen (Fig. 34) 0.31× as long as penis, ring narrow; endophallus ( Fig. 35) strongly ossification at end. Pygidium (Figs 37,42) in dorsal view male apex broadly rounded and female apex acuminate. Hindwing (Fig. 38): generally do not possess complete venation; oblong-ovate; gradually narrowing towards end and strongly narrowing towards base; radial field, apical, medial and anal field not apparent; at the middle part of anterior margin strongly ossified; with a setae at the end. Female sternite VIII and genitalia (Fig. 40) in lateral view coxites and styli 0.55× as long as sternum VIII. Spermatheca (Fig. 41) with corpus short, trapezoidal; cornu elongate, strongly curved into a narrow U-shape, apically gradually narrowed; nodulus and ramus not developed; spermathecal duct strongly sclerotized and curved.

Key to species of Leptomias occurring in Sichuan
Remarks. Its metanepisterna are posteriorly fused with the metaventrite and its scrobes are narrow, well defined and with the upper edge directed towards the lower end of eye, features well agreeing with the key characters of Geotragus. Chao (1980) described this species from a single male specimen. We later found additional specimens during several field trips, which allowed us to dissect 10 males and 10 females and illustrate the reduced hind wings and other important structures of the species . This species resembles Geotragus declivis Ren, Alonso-Zarazaga & Zhang, 2013 but differs by the following characters: prementum with 4 setae; elytral interstriae slightly elevated, unequal in width, without tubercles. It is similar to Geotragus shanensis Kumar, Mahendiran, Ayri & Ramamurthy, 2016, from which it can be distinguished by the following characters: pronotum with fine, incomplete, median longitudinal groove; protibiae only slightly bent inward at apical 1/4; bursal sclerite situated near junction of spermathecal duct and oviduct, ventral side of bursa copulatrix tile-like, in lateral view triangular, with several sharp tubercles ventrally, strongly sclerotized in middle.  (Chao, 1980): 25 male, dorsal view 26 male, lateral view 27 male, head and rostrum, anterior view 28 male, antenna, anterior view 29 male, left protibia, anterior view. Scale bars 1 mm. (Chao, 1980)