First record of the leafhopper genus Sweta Viraktamath & Dietrich (Hemiptera, Cicadellidae,Typhlocybinae) from China, with description of one new species feeding on bamboo

Abstract Sweta bambusana sp. n. (Hemiptera: Cicadellidae: Typhlocybinae: Dikraneurini), a new bamboo-feeding species, is described and illustrated from Guizhou and Guangdong of China. This represents the first record of the genus Sweta Viraktamath& Dietrich from China and the second known species of the genus. The new taxon extends the range of the genus Sweta, previously known only from northeast India and Thailand, considerably eastwards. A key for separation of the species of Sweta is given.


introduction
The leafhopper genus Sweta was established by Viraktamath and Dietrich (2011) based on the type species Sweta hallucinata Viraktamath & Dietrich, 2011, from northeast India and Thailand. This dikraneurine genus is remarkable because it shares features with another leafhopper subfamily, Signoretiinae, restricted to the Old World tropics (Viraktamath and Dietrich 2011).
During the course of studying species biodiversity of the bamboo-feeding leafhoppers in China (see Discussion), several specimens belonging to an undescribed species of the genus Sweta were found. The new species represents the first record of Sweta in China, and its discovery has broadened our knowledge of host plant and biogeography of the genus.

Materials and methods
Terminology used in this work follows Dietrich (2005). Dry specimens were used for the description and illustration. External morphology was observed under a stereoscopic microscope and characters were measured with an ocular micrometer. Measurements are given in millimeters; body length is measured from the apex of the head to the apex of the forewing in repose. The genital segments of the examined specimens were macerated in 10% KOH, washed in water and transferred to glycerine. Illustrations of the specimens were made with a Leica MZ 12.5 stereomicroscope. Photographs of the types were taken with a Leica D-lux 3 digital camera. The digital images were then imported into Adobe Photoshop 8.0 for labeling and plate composition. Nomenclature of leg setae follows Li et al. (2011). The type specimens are deposited in the Institute of Entomology, Guizhou University, Guiyang, China (IEGU), and the Natural History Museum, London (BMNH). Distribution. Oriental region (Fig. 19).

Sweta
Remarks. This dikraneurine genus is remarkable because it has a feature unknown in other typhlocybinae but present in another leafhopper subfamily (Signoretiinae), i.e. the elongate pronotum. A full description of the genus was given by Viraktamath and Dietrich (2011).
Male genitalia. Aedeagus with both pair of preapical processes curved laterally, lower pair slightly shorter than more dorsal pair (Figs 9, 10, 11); shaft apex blunt and rounded. Other features as in generic diagnosis.
Remarks. This new species is very closely related to S. hallucinata Viraktamath & Dietrich, 2011 from Thailand and India, but can be distinguished by the aedeagus with apex blunt and rounded (tapering in hallucinata); the lower pair of subapical processes slightly shorter than more dorsal pair (in hallucinata, the lower pair are distinctly longer than the more upper pair); male abdomen with the 3S apodemes extended to midlength of the segment V (extended to midlength of the segment IV in hallucinata); the female abdominal sternite VII more or less triangular (relatively rounded in hallucinata).

Discussion
Diversity of bamboo-feeding leafhoppers. The present authors have paid particular attention to the species of bamboo-feeding leafhoppers in their field research and collected large numbers of specimens in the past 15 years from China including a number of new taxa and new records (Chen and Li 1997;Li and Chen 1999;Chen et al. 2007Chen et al. , 2008Chen et al. , 2009Yang et al. 2007;Li et al. 2007Li et al. , 2011. Yang et al. (1999) recorded 13 species within 9 genera from China and  increased the number to 33 genera and 55 species (in 9 subfamilies), of which, 4 species belonged to Typhlocybinae. Clearly, throughout China, the species diversity of bamboo-feeding leafhoppers is very great with more than 87 species feeding exclusively on Bambusoideae (Chen et al. in press).
Host plant of new species. S. bambusana was found feeding exclusively on one species of native bamboo, Dendrocalamus affinis (Rendle) McClure (Figs 17, 18). No other information on biology of Sweta species, nor host plant damage caused, is available.
Distribution of Sweta species. Although both species of Sweta appear to be widespread in Southeast Asia (Fig. 19) they are very rare. The new species extends the range of the genus eastwards from northeast India and Thailand to China.