Review of the genus Vekunta Distant from China, with descriptions of two new species (Hemiptera, Fulgoromorpha, Derbidae)

Abstract The derbid genus Vekunta Distant, 1906 is reviewed. Two new species, V.bambusanasp. n. and V.pentaprocessusasp. n., are described and illustrated from the southwest of China to give the genus twenty-nine species in China. A checklist and a key to species of the genus from China are also provided.


Introduction
The planthopper family Derbidae (Hemiptera, Fulgoromorpha) was established by Spinola in 1839, containing three subfamilies in twenty tribes (Bourgoin 2018). Approximately eight tribes, 38 genera, and 154 species of Derbidae are known in China.
Almost all members of the family in China are distributed in the Oriental region, especially in southern China.
Herein, two new species, Vekunta bambusana sp. n. and V. pentaprocessusa sp. n., are described and illustrated from Guizhou and Yunnan provinces, China. A checklist and a key to species of the genus from China are also provided.

Materials and methods
The morphological terminology follows Bourgoin (1987) and Yang and Wu (1993). The morphological terminology of female genitalia follows Bourgoin (1993). Body length was measured from apex of vertex to tip of forewing. The standard terminology of venation follows Bourgoin et al. (2015). The term "anal style" used here follows Rahman et al. (2012). Dried specimens were used for the description and illustration. External morphology was observed under a stereoscopic microscope and characters were measured with an ocular micrometer. Color pictures for adult habitus were obtained by the Nikon SMZ25 system. The genital segments of the examined specimens were macerated in 10% NaOH and drawn from preparations in glycerin jelly using a Leica MZ 12.5 stereomicroscope. Illustrations were scanned with a Canon CanoScan LiDE 220 and imported into Adobe Photoshop CS5 for labeling and plate composition. The dissected genitalia were preserved in glycerin in small plastic tubes pinned together with the specimens.
The type specimens are deposited in the Institute of Entomology, Guizhou University, Guiyang, Guizhou Province, China (GUGC).
Male genitalia. Anal tube (Fig. 10) in profile broad at basal half, abruptly narrowed medially, apex evenly turned downward, directed ventrally, anal style sets at basal twofifths; in dorsal view (Fig. 11), length in middle line approximately three times as long as wide at middle, symmetrical, apical margin evenly incised medially. Pygofer (Fig. 10) in lateral view narrowed, dorsocaudal processes (Fig. 12) of pygofer asymmetrical, right dorsocaudal process distinctly longer than left one. Gonostyli (Fig. 10) bilaterally symmetrical, large, elongate and slightly reaching over apex of anal tube in lateral view, dorsal margin serrate at apex, curved dorsally, inner side of laterodorsal margin with a bifurcate process at base and a finger-shaped process medially. Phallus (Figs 13, 14) asymmetrical, periandrium curved, with a hooked process near middle ventrally directed caudally, apex with two spinous processes, below them with two sheet processes, all visible in both left and right lateral view. Aedeagus at base with a process curved dorsally, pointed ventrally, left side of aedeagus with a laminal process near middle, apex of aedeagus valviform, reaching to middle of periandrium. Female genitalia. Anal tube (Figs 15, 16) symmetrical and ring-shaped in dorsal view; apex of anal tube slightly exceeding apex of anal style. Abdominal sternite VII (Fig. 17) in ventral view symmetrical, posterior margin protruded medially, with protrusion length shorter than width at base, lateral margin widened toward the middle and then narrowed gradually toward apex, apical margin rounded. Gonapophysis VIII (Figs 17, 18) with nine teeth at ventral margin. Gonapophysis IX (Fig. 19) with two lobes incompletely symmetrical, lateral margin with dense setae, each lobe with a membrane sheet dorsally, blunt apically. Gonoplac (Figs 15, 17) in lateral view nearly rectangular, with a small angulate process at apex dorsally, lateral margin with spiniform setae.
Remarks. This species is similar to V. pentaprocessusa sp. n., but distinguished from the latter by: gonostyli (Fig. 10) symmetrical (gonostyli asymmetrical, with right gonostylus distinctly larger than left one in V. pentaprocessusa sp. n.); anal tube ( Fig. 11) of male symmetrical in dorsal view (asymmetrical in dorsal view in V. pentaprocessusa sp. n.); right dorsocaudal process (Fig. 12) of pygofer in dorsal view distinctly longer than left one in male (left dorsocaudal process in dorsal view slightly longer than right one in V. pentaprocessusa sp. n.); periandrium (Figs 13,14) with a hooked process near middle ventrally (periandrium with a hooked process near base ventrally in V. pentaprocessusa sp. n.); aedeagus (Figs 13,14) valviform at apex, reaching to middle of periandrium (aedeagus with five spinous processes at apex, the largest process reaching to base of periandrium in V. pentaprocessusa sp. n.).
Etymology. The species name is derived from the host plant scientific name, Bambusoideae.
Male genitalia. Anal tube (Fig. 25) in lateral view, obliquely, slender at basal half, apical margin rounded, anal styles sets at basal one-fifth; in dorsal view (Fig. 26),  length in middle line approximately three times as long as wide at middle, asymmetrical, apex rounded. Pygofer (Fig. 25) in lateral view distinctly narrowed medially, processes ( Fig. 27) of pygofer asymmetrical, left dorsocaudal process slightly longer than right one. Gonostyli (Fig. 25) bilaterally asymmetrical, right gonostylus larger than left one, large, elongate and slightly reaching less than apex of anal tube in lateral view, inner side with saccate process at basal two-thirds near ventral margin, left gonostylus with a small process rising from apical one-fifth of dorsal margin. Phallus asymmetrical, periandrium curved, with a hooked process near base ventrally directed caudally, in left lateral view (Fig. 28), with a slender process near middle, directed dorsocaudally, and two stout processes at apex, in right lateral view (Fig. 29), with a plate near apex, and a long process at apical two-thirds, slightly curved, directed dorsally, apical margin serrate. Aedeagus with five spinous processes at apex, the largest process produced reaching to base of periandrium, acute at apex.
Female genitalia. Anal tube (Figs 30, 31) symmetrical and ring-shaped in dorsal view; apex of anal tube slightly exceeding apex of anal style. Abdominal sternite VII (Fig. 32) in ventral view symmetrical, posterior margin protruded medially, with protrusion length shorter than width at base, apical margin rounded. Gonapophysis VIII (Figs 32,33) with eight teeth at ventral margin. Gonapophysis IX (Fig. 34) with two lobes incompletely symmetrical, lateral margin with dense setae, each lobe with a membrane sheet dorsally, blunt apically. Gonoplac (Figs 30,32) in lateral view nearly rectangular, with a small angulate process at apex dorsally, lateral margin with spiniform setae.
Remarks. This species is similar to V. fuscolineata Rahman et al., 2012, but distinguished from the latter by the slightly dark yellow mesonotum (Fig. 20) (mesonotum distinctly dark brown on each side, golden yellow in middle in V. fuscolineata); periandrium (Figs 28, 29) with a hooked process near base ventrally, directed caudally (periandrium without process ventrobasally in V. fuscolineata); anal tube of male (Fig. 26) asymmetrical in dorsal view (symmetrical in dorsal view in V. fuscolineata); gonostyli ( Fig. 25) asymmetrical, with right gonostylus distinctly larger than left one in lateral view (symmetrical in lateral view in V. fuscolineata).
Etymology. The new species name is derived from the Latin words penta-(five) and processus (process), referring to the apex of aedeagus with five processes in male.

Discussion
The genus Vekunta is a diverse genus in the subtropical and tropical regions of Australasian, Oriental, and Palaearctic regions (Löcker et al. 2009, Rahman et al. 2012).
To date, there are 43 species recorded in the world (Bourgoin 2018). Approximately 27 species of genus Vekunta are known in China, distributed in Zhejiang (one species), Yunnan (one species), Tibet (one species), and Taiwan (twenty-four species). Almost all members of the genus in China are distributed in the Oriental region, hence especially in southern China. Due to the original literature not recording host plants of this genus, many host plants are unknown. In our study, we find that V. bambusana sp. n. lives on bamboo in Guizhou, and some species of Vekunta we collected on weeds in some humid environments, for example, V. triprotrusa Wu & Liang, 2001. The new species V. pentaprocessusa sp. n. was collected by light trap. Thus, we speculate that this group prefers warm and moist environments and some species of the genus Vekunta have phototaxis. The natural environment of China is diverse, such as Yunnan Province (southern China), one of China's richest regions in terms of biodiversity; however, only one species of genus Vekunta has been recorded in this region, so we believe there should be more species of this genus waiting to be discovered in this region and other parts of China.