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Research Article
A new species of the genus Orthotemnus Wollaston, 1873 (Coleoptera, Curculionidae, Cossoninae) from China
expand article infoYoussef M. Omar, Runzhi Zhang§, Steve R. Davis|
‡ Chinese Academy of Sciences, Beijing and Assiut university, Assiut, Egypt
§ Chinese Academy of Sciences, Beijing and State Key Laboratory of IMPIR of China, Beijing, China
| University of Kansas, Lawrence, KS, United States of America
Open Access

Abstract

A new species, Orthotemnus longitarsus sp. n., is described from China, representing the first record of the genus Orthotemnus Wollaston, 1873 from China. Illustrations of diagnostic features of the new species and a key to all six species of the genus Orthotemnus (including O. reflexus Wollaston, O. disparilis Pascoe, O. filiformis Champion, O. expansus Hustache and O. ulmi Zherichin) are provided. All type specimens of the new species are deposited in the National Zoological Museum in the Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

Keywords

Weevil, Proecini , morphology, systematics, plectra, key, China, new record

Introduction

Based on the classification of Alonso-Zarazaga and Lyal (1999), Orthotemnus belongs to the tribe Proecini in the subfamily Cossoninae. The genus was erected by Wollaston (1873) for O. reflexus, described from specimens collected by Wallace in Dorey, New Guinea, as well as in Batchian, Makian and Ceram. Pascoe (1885) described a second species, O. disparilis, from Cape York, Northern Australia, and Champion (1914) a third, O. filiformis, from a single specimen (♀ ?) collected by Scott at Silhouette in the Seychelles. The fourth species, O. expansus, was described by Hustache (1955) based on one specimen collected from Watsa, Kibali-Ituri, D.R. Congo. Zherikhin (in Zherikhin and Egorov 1990) added the fifth species, O. ulmi, collected from rotten timbers of elm (Ulmus) at the Ussuriysk reserve in the Far East of the USSR. Morimoto (1973) and Zhang (1992) presented diagnostic features for the genus Orthotemnus in their respective keys to the Oriental and Chinese genera of Cossoninae (also see Folwaczny 1973).

The aim of this paper is to establish the first record of the genus Orthotemnus for China by describing a new species from Jiangsu province in eastern China and to provide a key to all the known species currently recognised in Orthotemnus.

Materials and methods

The type specimens of the new species are deposited at the Institute of Zoology (IOZ), Chinese Academy of Sciences (CAS), in Beijing, China. Morphological observations were made using a Zeiss Semi stereomicroscope Discovery V12, and photos were taken using a Micropublisher 5.0 RTV digital camera, model MP5.0-RTV-CLR-10A-color 10 BIT, attached to the same stereomicroscope. The recognition of the new species and the key to the species are based on comparison of the Chinese specimens with the original descriptions and illustrations of the previously described species.

All measurements were taken using an ocular micrometer. Abbreviations of characters given in the text are as follows: ACL – antennal club length; ACW – antennal club width; AFL – antennal funicle length; AL – antennal length; ASL – antennal scape length; BL – body length (excluding rostrum); EL – elytral length; EWB – elytral width at base; EWW – elytral width at widest part; PL – pronotal length; PW – pronotal width (widest part); RL – rostral length; RWA – rostral width at apex; RWB – rostral width at base.

Hind wing terminology follows Zherikhin and Gratshev (1995).

Taxonomic treatment

Orthotemnus Wollaston, 1873

Type species

Orthotemnus reflexus Wollaston, 1873: 489, by monotypy.

Diagnosis

Body (5.50–6.60 mm) not or slightly compressed longitudinally, elongate; derm glossy, glabrous, at most with sparse setae on elytra. Rostrum rather long and robust, much shorter than pronotum; longer than head; often wider before antennal insertion (equal width throughout: Wollaston (1873)). Antennae inserted above middle of rostrum in lateral view so that anterior part of scrobes visible from above; scapes reaching or passing hind margin of eyes, longer than funicles; funicles with seven segments. Head with forehead between eyes as broad as or broader than base of rostrum; postocular constriction not touching eyes. Eyes large, distance between eyes and postocular constriction shorter than diameter of eye. Pronotum not bisinuate at base (if weakly bisinuate, tarsal segment 5 broadest near base and tapering distally, or derm matt); triangular, truncate at base, as wide as elytral base. Elytra evenly parallel-sided, linearly truncated at base, not setose, recurved at their apex. Legs. with pro- and mesocoxae very widely and subequally separated, metacoxae less remote than pro- and mesocoxae; procoxae not very close to hind margin of prosternum; tibiae normal; tarsal groove of front tibiae not or bluntly pointed laterally; tarsi with segment 3 small, simple, entire or slightly notched, segment 5 normal, clavate, not compressed (Wollaston 1873, Hustache 1924, Morimoto 1973, Zhang 1992).

Orthotemnus longitarsus Omar & Zhang, sp. n.

Figs 1–4, 5–11, 12–18, 19–22, 23–31, 32–37, 38–40

Diagnosis

Rostrum widening after antennal insertion; scapes passing posterior margin of eye and reaching postocular constriction; temples swollen; forehead with short median furrow; sutural striae deep and depressed near scutellum; intervals smooth, equal, convex, with a single row of fine punctures, wider than striae; humeri truncate, quadrate; tarsi longer than tibiae.

Description

Measurements (male): BL: 3.29–3.40 mm; EL: 2.33–2.38 mm; EWB: 1.02–1.08 mm; EWW: 1.02–1.08 mm; PL: 0.96–1.02 mm; PW: 0.90–0.94 mm; RL: 0.52–0.55 mm; RWA: 0.31–0.34 mm; RWB: 0.25–0.30 mm; AL: 0.90–0.94 mm; ASL: 0.40–0.42 mm; AFL: 0.30–0.31 ACL: 0.20–0.22; ACW: 0.12–0.14 mm. Measurements (female): BL: 2.58–2.80 mm; EL: 1.70–1.90 mm; EWB: 0.84–0.96 mm; EWW: 0.84–0.96 mm; PL: 0.88–0.90 mm; PW: 0.77–0.78 mm; RL: 0.48–0.50 mm; RWA: 0.26–0.28 mm; RWB: 0.19–0.20 mm; AL: 0.70–0.90 mm; ASL: 0.32–0.40; AFL: 0.20–0.30; ACL: 0.13–0.20; ACW: 0.10–0.11 mm.

Body (Figs 15) oblong, curved, glossy.

Colour dark reddish-brown; rostrum, antennae and legs paler brown than body.

Figures 1–4. 

Orthotemnus longitarsus habitus. 1 ♂ dorsal aspect 2 ♂ lateral aspect 3 ♀ dorsal aspect 4 ♀ lateral aspect.

Figures 5–11. 

Orthotemnus longitarsus SEM photographs. 5 ♂ habitus, lateral aspect 6 enlargement of head and prothorax, lateral aspect 7 enlargement of lateral part of metathorax 8 enlargement of serrate dorsal margin of metaventrite 9 enlargement of left elytron 10 enlargement of apical half of rostrum, lateral aspect 11 enlargement of antennal club.

Rostrum (Figs 6, 10) long, more than 2 × longer than width at base, more or less 0.5 × as long as pronotum; narrow before antennal insertions (basal half), sides parallel, curved dorsally, widening after antennal insertion (in apical half), curved ventrally at antennal insertions; antennae inserted after middle of rostrum; with fine, subcircular, shallow punctures along dorsum, becoming oblong, denser towards apex; narrower at base than at apex; scrobes (Fig. 10). well-defined, deep, short, located in middle of rostrum, dorsal margin slightly lower than upper margin of eye, ventral margin black, visible in dorsal view.

Mouthparts. Maxillae (Fig. 25) with palpiger with large, slender seta near basolateral margin; galeo-lacinial complex with several large, tooth-like setae along margin, a few smaller, slender setae near base. Labium (Fig. 26) with prementum elongate, lacking setae; 1st segment of palpus with 2 setae, 2nd segment with 1 seta, 3rd (apical) segment lacking setae. Right mandible (Fig. 24) with 3 teeth and a small molar region, primary tooth largest, second and third teeth smaller; left mandible (Fig. 23) mainly with large primary tooth and molar region, other teeth reduced to small ridges.

Antennae (Figs 1012) pale, long, glossy brown, clubs pilose; scapes slightly bent at middle, thick and widening in distal third, widened part with sparse, shallow, oblong punctures with fine suberect setae, smooth, passing posterior margin of eye, approaching postocular constriction, approximately as long as or slightly shorter than funicle; clubs compact; funicles with all segments with few fine, erect setae, loose, segment 1 stout, longer than wide, segments 2–5 subequal, 6 and 7 wider than long, 7 wider than 6; clubs (Fig. 11). longer than wide, oval, slightly laterally flattened, 3-segmented, setigerous, setae suberect towards apex, acuminate.

Figures 12–18. 

Orthotemnus longitarsus SEM photographs. 12 antenna 13 ♂ abdominal tergites 14 enlargement of portions of tergites 5 and 6 showing spiculate patches 15 enlargement of tergite 7 showing rows of plectra 16 enlargement of plectra on tergite 7 17 ♂ abdominal venter 18 enlargement of apical portion of ventrite 5.

Head oval, laterally constricted behind eyes, constriction weak dorsally, temples swollen, with subcircular punctures, fine sparse punctures behind postocular constriction, wrinkled, glossy; forehead slightly convex, broader than rostral base, with clear circular punctures, interspaces 2–3 × puncture diameter, with short median longitudinal furrow; vertex bulbous, convex, wrinkled. Eyes oval, widely separated, convex, with coarse, convex facets.

Pronotum conical, anteriorly constricted, deep laterally but weak dorsally, forming collar with large, circular punctures throughout, punctures separated by approximately 1–2 × their diameter, with abbreviated smooth median line not reaching anterior and posterior margins, dorsally and laterally convex, truncate along posterior margin.

Mesonotum (Fig. 29) typical of Cossoninae; axillary cord enlarged, lateral margins rounded.

Scutellum visible, transverse-oblong, smooth, dull.

Metanotum (Fig. 30) with metascutum reaching posterior margin of notum; scutellar groove nearly reaching posterior margin of notum; allocrista angular at anteromesal angle.

Metendosternite (Fig. 28) stalk slightly taller than wide; longitudinal flange short; furcal arm slender, bifid at apex; hemiductus slender.

Proventriculus as in Fig. 27.

Elytra (Figs 5, 9) glossy, long, disk convex, lateral margins parallel until declivity, base truncate, slightly broader than pronotal base; striae with large, deep circular punctures, punctures separated by approximately 1–1.5 × puncture diameter, first stria (sutural stria) deeper and depressed near scutellum; intervals smooth, equal, convex, with a single row of fine punctures, wider than striae; sutural interval deeper and depressed near scutellum, dilated at declivity to apex, interval 3 elevated caudally of declivity, with more than one row of fine punctures; intervals 4, 5 and 6 connected slightly caudally of declivity but not reaching apex; interval 9 forming oblique, ridged elevation caudally of declivity and connected to interval 3, not reaching apex; humeri truncate, quadrate.

Hindwings (Fig. 31) slender, lacking jugal area (anal lobe); Rr slender, abbreviated, not reaching rcm; rc absent; 1rs triangular and larger than 2rs; R3 absent; Cu1 not reaching posterior margin; r-m absent; A simple, other anal veins absent.

Thoracic sterna flat; prosternum wrinkled, with deep circular punctures; procoxae separated by 0.5 × diameter of coxa; mesoventrite flush with prosterum, base bisinuate, mesocoxae separated by approximately coxal diameter; metaventrite transverse, longitudinal sulcus from base to beyond middle, with circular punctures spaced by 2–3 × diameter of puncture, meta coxae separated by slightly less than 2 × diameter of coxa; dorsal margins of metaventrite serrate (sclerolepidial setae absent, though setal sockets present; Figs 78).

Legs (Figs 1922). Femora glossy, robust along distal two-thirds, with small, circular, sparse punctures, separated by approximately 2–4 × puncture diameter, slightly less than 2 × length of tibia; tibiae with smaller, similarly spaced punctures, straight, nearly uniform in width; uncus small, at outer apical margin, approximately 0.5 × as long as tarsomere 5, praemucro at inner apical margin covered by a small tuft of setae; tarsi longer than tibiae, 5-segmented; segments 1–3 with long, pale yellowish setae, 1 2 × longer than wide; 2 subequal in length and width; 3 wider than long, notched; 4 small, 5 longer than others combined, curved, dorsally convex, glossy, with appressed pale yellowish setae; claws simple, free.

Figures 19–22. 

Orthotemnus longitarsus SEM photographs of legs. 19 foreleg 20 middle leg 21 hindleg 22 enlargement of hind tarsus.

Figures 23–31. 

Orthotemnus longitarsus mouthparts, internal structures and hindwing. 23 left mandible 24 right mandible 25 maxilla 26 labium 27 proventriculus 28 metendosternite 29 mesonotum 30 metanotum 31 hindwing: C = Costa Sc = Subcosta Rr = radial recurrent vein R = Radius rcm = margin of radial cell 2rs, 1rs = radial sclerites pst = postradial stripe mst = medial stripe Cu = Cubital A = Anal.

Abdomen.Tergites (Figs 1316) with microtrichial wing-locking patches restricted to posterior half of tergites 2–5 and present on most of tergite 6; two linear rows of plectra present on tergite 7 (Lyal and King 1996). Ventrites (Fig. 17, 18). glossy, 1 and 2 with large, circular punctures, punctures separated by 2–3 × their diameter; 1 broader than 2, projecting between metacoxae, 1 and 2 clearly separated; 3 and 4 narrow, equal, each with two rows of punctures, basal row with large, deep, oblong punctures, apical row with fine small punctures, with fine suberect setae apically; 5 transverse, posterior margin rounded, with large, oblong, deep punctures at base, punctures becoming sparse and subcircular apically with some appressed setae.

Male terminalia and genitalia (Figs 3237). Spiculum gastrale of sternite IX with flattened, expanded apex; apex approaching size of sternite at base. Sternite VIII divided, with 2 setae on each hemisternite. Tegmen complete; manubrium nearly 0.5 × length of tegmen. Penis with temones ca. 4.5 × body of penis; apical margin setose; endophallus (internal sac) extensive, greater than 0.5 × length of temones, bearing several internal sclerites from approximate middle of endophallus to its apex.

Figures 32–37. 

Orthotemnus longitarsus ♂ terminalia. 32–33 Penis, lateral aspect 34–35 aedeagus, dorsal aspect 36 sternites VIII and IX 37 tegmen.

Female terminalia and genitalia (Figs 3840). Gonocoxites of typical form; oblong; styli elongate, narrow. Spermatheca approximately crescent-shaped. Sternite VIII with spiculum ventrale gradually narrowing towards apex; base with many setae, setae mostly bifid at middle of base and mostly simple laterally; many microtrichia along basal region of sternite anteriorly of setae.

Figures 38–40. 

Orthotemnus longitarsus ♀ terminalia. 38 ovipositor (coxites and styli) 39 spermatheca 40 sternite VIII.

Material examined

Holotype: male: China: Jiangsu: Jiangsu Province, Nanjing, Zijingshan, 32.30°N, 118.49°E, 05 III 2008, collected by Liang Ding (IOZ). Paratypes: 4 ♀ and 4 ♂: same data as holotype; found under trees in park.

Etymology

The specific epithet is a combination of the Latin word longus and the Latinized Greek word tarsus, referring to the longer tarsus in relation to the tibia; it is a noun in apposition.

Distribution

China: Jiangsu Province: Nanjing, Zijingshan.

Sexual dimorphism

The female (Figs 34) is smaller than the male (Figs 12), and its rostrum is slightly shorter and slenderer than that of the male. Males also have concave first and second ventrites, the first slightly more projected between the metacoxae than in the female.

Discussion

The new species here differs from other species of the genus as detailed in the key below as well as in the following features: its large size; the rostrum narrow and strongly convex, narrow basally after the antennal insertions but widening distally; the forehead with a short, median longitudinal furrow starting in the basal half and extending posteriad; the long scapes reaching the postocular constriction; the swollen temples; the transverse-oblong scutellum; the quadrate humeri; the parallel-sided tibiae; the tarsi being longer than the tibiae. This species marks the first record of the genus for China.

The genus is currently known to comprise six species, including the one newly described here, distributed as follows: O. reflexus and O. disparilis in the Australian, O. filiformis and O. expansus in the Afrotropical and O. ulmi and the new species in the Palaearctic region (Csiki 1936, Alonso-Zarazaga and Lyal 1999, Setliff 2007). The genus has seemingly not been recorded from the Nearctic, Neotropical, nor Oriental regions. This distribution suggests that the genus may occur more widely in the Old World including the Oriental region.

Key to the species of Orthotemnus

1 Apical margin of elytra reflexed or recurved 2
Apical margin of elytra normal, subacute 4
2 Elytral intervals flat, obsoletely punctate; prothorax conical, strongly constricted before apex; closely, rather coarsely punctate, except along abbreviated narrow median space; interspaces finely alutaceous O. filiformis
Elytral intervals depressed or weakly convex, finely shagreened or sparsely and finely punctate; prothorax slightly constricted or with flat constriction not reaching disc at apex 3
3 Rostrum longer than pronotum, equal breadth throughout, with fine, dense, shallow punctures; prothorax elongate, triangular, with evenly sparse, moderately deep punctures; base truncate and as broad as elytra, weakly constricted at apex O. reflexus
Rostrum shorter than pronotum (4:5), conical, gradually narrowing from base to apex, with fine sparse punctures; short elongate fovea between antennal insertions; prothorax less elongate than in O. reflexus; punctures round, shallow, rather dense, unevenly distributed; base weakly bisinuate, slightly narrower than elytra O. ulmi
4 Antennae inserted before middle of rostrum; rostrum strongly curved at middle or at point of antennal insertions 5
Antennae inserted behind middle of rostrum; rostrum slightly curved O. expansus
5 Prothorax small, oblong, with large coarse punctures; elytra short, gradually narrowing to apex; striae with large, dense, quadrate punctures O. disparilis
Prothorax conical, constricted anteriorly; constriction deep laterally and weak dorsally, with large, circular punctures throughout; elytra long, parallel-sided until declivity; striae with large, deep, circular punctures O. longitarsus sp. n.

Acknowledgments

Sincere thanks are due to Dr. Boris Alexandrovich Korotyaev (Laboratory of Insect Systematics, Zoological Institute, Russian Academy of Sciences, Russia) and Dr. Aly M. Ragh (Université d’Angers, France) for their kind help. This work was supported by a CAS-TWAS Post-Doctoral Fellowship Program as well as the NNFC programs (31210103909/31172130/J1210002). Partial funding also was provided by the University of Kansas Entomology Endowment and the US National Science Foundation grant DEB1110590 (to M.S. Engel, P. Cartwright, and S.R. Davis).

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