A new bamboo-feeding planthopper genus Aodingus Chen & Li (

. A new planthopper genus, Aodingus Chen & Li gen. nov. and three new species ( A. hainanensis Chen & Li gen. et sp. nov., A. obscurus Chen & Li gen. et sp. nov. and A. cuongi Chen & Li gen. et sp. nov.) are described from China and Vietnam. The new genus is superficially similar to Procidelphax Bartlett, 2009 in general appearance in that the body is strongly dorsoventrally flattened. Distinctive features of the new taxon include broadly compressed body with vertex broad, apical margin broadly rounded, middle part concave, median and submedian carinae absent, frons broad and large, wider at base than at apex, forewing broad and long, aedeagus tubular, curved ventrally. A diagnosis for all species, illustrations and an identification key of new genus are provided. A key to the Chinese genera of Tropidocephalini is also provided.


Introduction
The planthopper tribe Tropidocephalini Muir, 1915 is the second largest clade of Delphacidae Leach, 1815 containing 37 genera and 198 species, distributed in the Oriental, Palaearctic, Afrotropical, Australian and Pacific Regions of the world, but most species, feeding on bamboos, are recorded from the Oriental Region (Chen & Tsai 2009;Bourgoin 2022).In China, Tropidocephalini currently comprises 113 species in 23 genera, representing the richest species diversity of this tribe worldwide (Chen 2003;Ding 2006;Chen & Tsai 2009;Qin & Zhang 2010;Hu & Ding 2013;Ren et al. 2014).Tribal characters are a thickened calcar which is concave on the inner surface and the trailing margin lacking the teeth.The central sperm conducting tube of the membranous aedeagus is within a sclerotized theca.The phallotheca and anal segment are in close functional contact, with the base of the phallotheca mostly integrated into the ventral side of the anal segment.The base of the phallotheca is usually asymmetrically twisted, bearing at least one slender process arising from the base (Asche 1990;Bartlett 2009).
A new genus and three new species are described and illustrated herein.In the new genus, the posttibial spur is large and thick, concave on inner surface and without teeth along the hind margin; the aedeagus and anal segment are in close functional contact, with the base of the aedeagus integrated into the ventral side of the anal segment; the base of the aedeagus is asymmetrical, bearing a slender process arising from the base.The features of the post-tibial spur and of the male genitalia place this genus in the Tropidocephalini.The main diagnostic features are described and illustrated, and further information on host plants and geographical distribution of the three new species are included.

Material and methods
The morphological terminology follows Yang & Yang (1986).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-6000 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 ver.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).

Etymology
The name is derived from the transliteration of the Chinese 'aoding', meaning the middle part of vertex is concave.It is masculine in gender.

Diagnosis
The salient features of the new species include the following: forewings (Fig. 1A) uniformly yellowish brown; lateral margins of basal part of frons (Figs 1E, 2B) with short yellowish white transverse markings; ventral margin of aedeagus (Fig. 2F) with a small process medially.

Etymology
This new species is named after the type locality, Hainan Province, China.
Coloration.General color yellowish brown with dark brown markings (Fig. 1A-F).Vertex yellowish brown, carinae brown (Fig. 1C).Frons dark brown except apical part yellowish white, lateral margins of basal part with short yellowish white transverse markings.Clypeus yellowish brown, lateral carinae brown.Genae pale yellowish white except areas below level of lower margin of eyes dark brown, lateral carinae brown.Eyes reddish brown.Antennae with first segment brown dorsally and yellowish brown to pale brown ventrally, second segment pale brown, middle part dark brown (Figs 1D-E, 2B).Pronotum and mesonotum yellowish brown (Fig. 1C).Forewing yellowish brown, veins brown (Figs 1A, 2C).Wings pale brown, veins brown.Legs pale yellowish brown to brown (Fig. 1F).Thorax with ventral part pale yellowish brown, lateral areas with dark brown markings.Abdomen brown to dark brown.Male pygofer and anal segment dark brown.

Diagnosis
The salient features of the new species include the following: forewings (Fig. 3A) uniformly yellowish brown; lateral margins of basal part of frons (Figs 3E, 4B) without short yellowish white transverse markings; ventral margin of aedeagus (Fig. 4F) without small process medially.

Etymology
The specific epithet is derived from the Latin word 'obscuru', referring to the dark brown body.
Coloration.General color yellowish brown to dark brown (Fig. 3A-F).Frons dark brown except apical part yellowish white, carinae brown.Clypeus dark brown.Genae pale yellowish white except areas below level of lower margin of eyes dark brown.Eyes reddish brown.Antennae yellowish brown (Figs 3D-E, 4B).Vertex, pronotum and mesonotum yellowish brown to dark brown (Fig. 3C).Forewing yellowish brown, veins brown (Figs 3A, 4C).Legs yellowish brown (Fig. 3F).Thorax with ventral part pale yellowish brown, lateral areas with dark brown markings.Abdomen brown to dark brown.Male pygofer and anal segment dark brown.

Diagnosis
The salient features of the new species include the following: forewings brown (Fig. 6C) to dark brown, basal ⅓ with wide transparent transverse band, anterior margin with 2 transparent spots in distal ⅓.

Etymology
This species is named in honour of the collector of the specimens, Dr Ha-Viet Cuong.Coloration.General color yellowish brown to brown with dark brown markings (Fig. 5A-F).Frons black except apical part yellowish white, lateral margins of basal part with short yellowish white transverse markings, median line yellow.Clypeus yellowish brown, lateral carinae dark brown.Genae yellowish brown except areas below level of lower margin of eyes dark brown.Eyes reddish brown.Antennae with first segment with median and apical parts dark brown, second segment with median and apical dorsal parts brown to dark brown (Fig. 5D-E).Vertex, pronotum and mesonotum yellowish brown to dark brown (Fig. 5C).Forewings brown to dark brown, basal ⅓ with wide transparent transverse band, anterior margin with 2 transparent spots in distal ⅓, veins dark brown (Fig. 6C).Wings smoke brown, veins dark brown.Legs pale yellowish brown to brown (Fig. 5F).Thorax with ventral part brown, lateral areas with dark brown markings.Abdomen brown to dark brown.Male pygofer and anal segment dark brown.

Discussion
The biological knowledge of the species in this genus is currently limited.According to a field investigation of bamboo diseases led by Prof. Ha-Viet Cuong (Hanoi University, Vietnam), it was found that adults and nymphs of A. cuongi gen.et sp.nov.mainly harm a bamboo called Dendrocalamus membranaceus Munro, 1868, which is widely distributed in Vietnam.This species is mainly concentrated on bamboo shoots, as shown in Figures 7-8, which causes serious harm to the local bamboo in Vietnam.This pest is likely to be a vector insect for transmitting bamboo phytoplasma diseases, which caused greater damage than direct feeding.Species of Aodingus Chen & Li gen.nov.from China are collected from the leaves of bamboo and are currently less harmful due to smaller occurrence.However, A. cuongi gen.et sp.nov. is of economic significance due to large populations feeding on the bamboo in Vietnam, which may be related to the local climate.Species of Aodingus Chen & Li gen.nov.feed exclusively on bamboo.So far, this genus is only known to be distributed in southern China (Hainan and Yunnan) and northern Vietnam (Thanh Hoa).Huang et al. (2020) provides a two-clade system in Tropidocephalini, including Bambusiphagina and Tropidocephalina.Members of the Tropidocephalina are more robust (slightly to distinctly), head width varied and in some forms anteriorly produced, frons relatively broad, lateral margins often arched, some with clypeus at an angle to the frons (in lateral view), antennae often short, wings varied, outline parallel sided to modified (Huang et al. 2020).In the new genus, body is robust, vertex broad, apical margin rounded, frons broad, lateral margins convex outward distinctly, forewings opaque, outline parallel sided.Based on superficial features, we anticipate that the new genus belongs in the Tropidocephalina.