A new species of the genus Orthotemnus Wollaston, 1873 (Coleoptera, Curculionidae, Cossoninae) from China

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 Orthotemnus reflexus Wollaston, Orthotemnus disparilis Pascoe, Orthotemnus filiformis Champion, Orthotemnus expansus Hustache and Orthotemnus 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.


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.

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 parallelsided, 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 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 ( Body (Figs 1-5) oblong, curved, glossy.
Colour dark reddish-brown; rostrum, antennae and legs paler brown than body. 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.
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.
Female terminalia and genitalia (Figs 38-40). 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.
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 3-4) is smaller than the male (Figs 1-2), 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.