Two new species of the bamboo-feeding planthopper genus Neobelocera Ding & Yang, 1986 from China (Hemiptera, Fulgoroidea, Delphacidae)

Two new species of the bamboo-feeding genus Neobelocera Ding & Yang, 1986, N. biprocessa sp. nov. and N. russa sp. nov., are described and illustrated from southwest China (Hainan and Guizhou), giving the genus nine species in total. A key is provided to separate all species.


Introduction
The family Delphacidae Leach, 1815 is the most diverse and cosmopolitan group of the superfamily Fulgoroidea Kirkaldy, 1907, with approximately 2210 described species in 426 genera, of which the vast majority (80%) belongs to the most species-rich subfamily Delphacinae Muir, 1915(Urban et al. 2010Huang et al. 2017;Yu & Liang 2018;Bourgoin 2019). It is easy to distinguish from all other fulgoroids by the character of a movable spur at the end of the hind tibia ). Members of the group feed on the phloem tissues of host plants, and a variety of species are economically signifi cant pests of many important crops, such as rice, maize, wheat, barley, sugarcane and bamboo. Of these species, most incur direct damage to plants through feeding and oviposition (Wilson & O'Brien 1987;Wilson 2005;Urban et al. 2010). Within the subf amily Delphacinae, 55 species are recognized as economically signifi cant pests, incurring damage to approximately 25 plant crops (Wilson & O'Brien 1987;Huang et al. 2017). Moreover, approximately 30 delphacid species also serve as vectors of 28 plant pathogens (Wilson & O'Brien 1987;Wilson 2005;Hogenhout et al. 2008;Urban et al. 2010;Huang et al. 2017).

Material and methods
The morphological terminology follows Hou & Chen (2010). The standard terminology of venation follows Bourgoin et al. (2015). Dry male 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 KEYENCE VHX-1000 system. The genital segments of the examined specimens were macerated in 10% KOH and drawn from preparations in glycerin jelly using a Leica MZ 12.5 stereo microscope. Illustrations were scanned with a Canon CanoScan LiDE 200 and imported into Adobe Photoshop 6.0 for labeling and plate composition.
The type specimens of the new species are deposited in the Institute of Entomology, Guizhou University, Guiyang, China (GUGC).

Diagnosis
The genus Neobelocera is easily distinguished from other genera of Tropidocephalini by the following combination of characters: antennae with fi rst segment subsagittate, markedly fl attened, a longitudinal carina down middle, the ventral apical angle longer than dorsal apical angle (Figs 1E, 2B, 3E, 4B); when postclypeus viewed in profi le, apical part of median carina bent at rounded angle, not at right angle (Figs 1D, 3D) (Hou & Chen 2010;Hu & Ding 2014).

Host plant
Bamboo.

Host plant
Bamboo.

Remark
This species was described from Yunnan Province, China based on two male and one female specimens deposited in GUGC by X.S. Chen (2003). This species is here recorded from Guizhou Province, China for the fi rst time. of pygofer concave U-shape, without process (Fig. 2F); phallus with basal half broad, compressed, apical half slender, tubular, curved ventrally, acute at apex, with spinous process at basal ⅓ and node subapically (Fig. 2G); phallobase with long straight spinous process basally and three processes apically (Fig. 2G); genital styles in posterior view inner margin with two processes (Fig. 2H).

Etymology
The species epithet is derived from the Latin words 'bi-' and 'process', referring to the inner margin of genital styles with two processes.
COLORATION. General coloration yellowish white to brown (Fig. 1A-F). Vertex, pronotum, mesonotum yellowish white, pronotum and mesonotum with lateral areas brown, base of pronotum, middle areas of mesonotum somewhat light yellow (Figs 1C, 2A). Frons and genae yellowish brown, except broad transversal stripe below level of lower margin of eyes and narrow stripe of apex yellowish white, along near apex of median carina of frons and inner margin of lateral carinae of genae with several short transversal stripes, yellowish white. Clypeus with basal half yellowish white and apical half dark brown (Fig. 1E). Rostrum yellowish brown, except apex dark brown. Eyes yellowish brown. Ocelli reddish brown. Antennae brown, except lateral margins of fi rst segment yellowish white (Fig. 1E). Legs yellowish white to brown, with dark maculations. Forewing light yellowish white, almost hyaline, basal part near costal margin with big infuscate markings, and apical part from transverse veins to apex with dark brown markings, veins with white spots (Fig. 1F). Wings hyaline with veins dark brown.

Host plant
Bamboo.

Remarks
This new species is assigned to the genus Neobelocera because the antennal segment I is subsagittate, markedly fl attened, with a median longitudinal carina, the ventral apical angle longer than the dorsal apical angle (Fig. 2B). This species is similar to N. asymmetrica Ding & Yang, 1986 in having the vertex short relatively ( Fig. 2A), forewing broad and about 2.7 times as broad as median length, apical margin acutely rounded, with blackish brown markings, and veins with white spots or white short stripes at intervals (Fig. 1F), frons with broad transversal stripe below level of lower margin of eyes yellowish white, along near apex of median carina with several short transversal stripes, yellowish white (Fig. 1E), genae with 2-3 light brown spots (Fig. 1E), male pygofer with ventral margin concave U-shape, without process (Fig. 2F). However, it can be distinguished from the latter by the following features: (1) phallus ( Fig. 2G) with basal half broad, compressed, apical half slender, tubular, curved ventrally, acute at apex, with process at basal ⅓ and node subapically (in N. asymmetrica, phallus tubular, rounded at apex, without process and node); (2) phallobase (Fig. 2G) curved at basal ⅓, 7-shaped, with long straight spinous process basally and three processes apically ( in N. asymmetrica, phallobase slender, long and curly, spine-like); (3) genital styles (Fig. 2H) in posterior view inner margin with small processes medially and at basal ⅓ (in N. asymmetrica, genital styles in posterior view inner margin without process medially, with a nipple-like process at subapical ⅓).

Diagnosis
The salient features of the new species include the following: frons brown, except broad transversal stripe between ocelli and narrow stripe at apex yellowish white, along near apex of median carina with several short transversal stripes, yellowish white (Fig. 3E); genae with 2-3 light brown spots (Fig. 3E); antennal segment I subsagittate, markedly fl attened, with median longitudinal carina, the ventral apical angle longer than dorsal apical angle (Fig. 4B); ventral margin of pygofer with 3 medioventral processes short, median one slightly longer than lateral ones (Fig. 4D); genital styles swollen subapically (Fig. 4H).

Etymology
The species epithet is derived from the Latin word 'russa', referring to the body with rust color. COLORATION. General coloration dark yellowish brown (Fig. 3A-F). Vertex, pronotum, mesonotum dirty yellowish brown, except Y-shaped carina of vertex, all carinae of pronotum and mesonotum yellowish white (Fig. 3C). Frons and genae brown, except broad transversal stripe below level of lower margin of eyes and narrow stripe of apex yellowish white, along near apex of median carina of frons and inner margin of lateral carinae of genae with several short transversal stripes, yellowish white. Clypeus yellowish brown to brown (Fig. 3E). Eyes dirty yellowish brown. Ocelli reddish brown. Antennae brown, except lateral margins of fi rst segment yellowish white (Fig. 3E). Legs yellowish white, with dark brown maculations. Forewing light yellowish white, almost hyaline, basal part near costal margin with big infuscate markings, and apical part from transverse veins to apex with dark brown markings, veins with white spots (Fig. 3F). Wings hyaline with veins dark brown. HEAD AND THORAX. Head including eyes almost as wide as pronotum (Fig. 4A). Vertex wider at base than long medially about 2.57: 1 (Fig. 4A). Frons in middle line longer than wide at widest part about 1.74: 1, widest above level of lower margin of eyes. Postclypeus at base almost as wide as frons at apex (Fig. 4B). Antennae with fi rst segment shorter than second segment about 0.65: 1, second segment cylindrical, longer than wide about 2.80: 1 (Fig. 4B). Pronotum subequal to vertex medially. Mesonotum longer than vertex and pronotum combined about 2.25: 1 (Fig. 4A). Forewing longer in middle line than wide at widest part about 3.25: 1 (Fig. 4C). MALE GENITALIA. Anal segment small, ring-like (Fig. 4D). Pygofer in profi le much longer ventrally than dorsally (Fig. 4E), in posterior view with opening longer than wide, ventral margin with three medioventral processes, median one longer than lateral ones, truncate apically, lateral ones stout, tapering (Fig. 4D). Aedeagus (Fig. 4F-G) with phallobase, phallus tubular, bent ventrad medially, with node at apex, middle dorsal with a spinous process, directed dorsad, apex with 2 long spinous processes. In addition, 2 processes at subapical part of phallus, right one strongly curved. Phallobase slender, tubular, arising from base of aedeagus, running dorsad, then curving caudad, after median part, turned left then ventrad, tapering apically. Genital styles simple, long, reaching to ventral margin of anal segment, swollen subapically (Fig. 4H).

Host plant
Bamboo.

Remarks
This new species is assigned to the genus Neobelocera because the antennal segment I is subsagittate, markedly fl attened, with a median longitudinal carina, the ventral apical angle longer than dorsal apical angle (Fig. 4B). This species is similar to N. lanpingensis Chen, 2003 in having the body elongate ( Fig. 3A-B), forewings long and narrow, apex oblique and tapering, with blackish brown markings, and with white spots or white short stripes at intervals (Fig. 3F), frons with pale transverse band below level of lower margin of eyes (Fig. 3E), male pygofer with medioventral processes (Fig. 4D), phallus with four spinous processes at apex and near apex, phallobase slender and long (Fig. 4F-G). However, it can be distinguished from the latter by the following features: (1) frons (Fig. 3E) along near apex of median carina with several short transversal stripes, yellowish white (in N. lanpingensis, frons without yellowish white transverse stripes subapically); (2) genae ( Fig. 3E) with 2-3 light brown spots (in N. lanpingensis, genae without light brown spot); (3) medioventral processes of pygofer ( Fig. 4D) with median one longer than lateral ones, truncate apically, lateral ones stout, tapering ( in N. lanpingensis, medioventral processes with median one short, tapering, lateral ones very slender, long, sinuate); (4) genital styles (Fig. 4H) swollen subapically (in N. lanpingensis, genital styles tapering apically).

Discussion
Our species-level review of Neobelocera based on morphology increased the species-richness of the genus by two species named and described above. Despite the fact that species of Neobelocera are quite similar in appearance, the structure of male genitalia is varied. For example, N. biprocessa sp. nov. and N. russa sp. nov. are easily distinguished from the other species in the genus based on the shape of the aedeagus and the genital styles, but the male genitalia of these two species and the rest of the species in the genus are homogenous.
Of the genera of the tribe Tropidocephalini, only three, Bambucibatus Muir, 1915, Belocera Muir, 1913 and Neobelocera, have the antennae fl attened, sagittate or subsagittate. However, these three genera are substantially different and the differences were discussed by Hou & Chen (2010).
The phylogenetic work of Huang et al. (2017), obtained from a maximum likelihood analysis of four genes (cox1, cytb, 16S rDNA and 28S rDNA), places Neobelocera (using Neobelocera sp.) as sister to a clade of Arcofaciella Fennah, 1956, Tropidocephala Stål, 1853, Carinofrons Chen & Li, 2000, and Epeurysa Matsumura, 1900. The monophyly of Neobelocera was supported. Nevertheless, the lack of DNA sequence data for the rest of the species in the genus Neobelocera hinders further investigation of their taxonomic status as well as their relationships to determine pairs of sister taxa. Additional work remains to be done on the genus, such as a molecular phylogenetic analysis.
Although the host plant of two species, Neobelocera hanyinensis and N. medogensis, are still unknown, most of species in the genus Neobelocera were found to feed exclusively on bamboo (Poaceae, Bambusoideae) (Ding et al. 1986;Zhu 1988;Ding & Hu 1991;Chen 2003;Chen & Liang 2005;Hou & Chen 2010). China is one of the world's bamboo center production areas, with more than 500 species of bamboo plants in total. Up to now, nine species of Neobelocera have been reported from China. However, some species remain unknown and await descriptions.