﻿Four new species of the genus Andixius Emeljanov & Hayashi (Hemiptera, Fulgoromorpha, Cixiidae) from China

﻿Abstract Four new species of the genus Andixius Emeljanov & Hayashi, 2007 are described and illustrated from China. These are A.flagellihamus Wang & Chen, sp. nov., A.gracilispinus Wang & Chen, sp. nov., A.productus Wang & Chen, sp. nov. and A.truncatus Wang & Chen, sp. nov. Photographs of the new species and an identification key to all Andixius species are provided.


described two new species:
A. cultratus and A. lingulatus.
Recent study of some Chinese specimens has found four new species, A. flagellihamus Wang & Chen, sp. nov., A. gracilispinus Wang & Chen, sp. nov., A. productus Wang & Chen, sp. nov. and A. truncatus Wang & Chen, sp. nov., which are described here. Hence, the number of Andixius species is now 10, with nine species occurring in China.

Materials and methods
The morphological terminology follows Bourgoin (1987) and Bourgoin et al. (2015). The morphological terminology of female genitalia follows Bourgoin (1993). Dry specimens were used for the descriptions and illustrations. Body length was measured from the apex of the vertex to the tip of the forewing; vertex length was measured at the median length of the vertex (from the apical transverse carina to the tip of the basal emargination). Observations and drawings of external morphology were made with the aid of a Leica MZ 12.5 stereomicroscope. Photographs of the types were taken with the Keyence VHX-1000 system. Illustrations were scanned with a CanoScan LiDE 200 scanner and imported into Adobe Photoshop CS7 for labelling and plate composition. The dissected male genitalia are preserved in glycerine 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 (IEGU).
Distribution. China (Xizang) (Fig. 12). Etymology. The specific name is derived from the Latin adjective flagellihamus, referring to the 1-hooked spinose process arising from the apex of the endosoma. Remarks. This species can be distinguished from the other species of the genus by the following characters: basal right side of periandrium with a U-shaped spinose process; basal ventral margin of periandrium with a long spinose process, apex curved upwards, forming a hooked process; apex of endosoma with a hooked spinose process.   Coloration. General color yellowish brown (Figs 1C, D, 4A, B). Eyes black-brown, ocelli faint light yellowish brown, semitranslucent. Lateral margin of frons yellowish brown, behind eyes with an off-white spot. Antenna and vertex yellowish brown. Face and rostrum dark fawn. Pronotum and mesonotum black. Forewing semitranslucent, with veins, stigma, and tubercles black-brown; basal and middle part of forewings with an inner oblique stripe; base and lateral margin black-brown; in front of fork CuA 1 +CuA 2 with a pale spot; costal vein with three small, spaced, dark brown spots; behind stigma and near claval fork with an irregular puce spot; apical half of wing with brown patches. Hind tibiae light brown. Ventral abdomen brown. Head and thorax. Vertex (Figs 1C, 4A) 1.37 times longer than wide; anterior margin slightly curved, recessed; posterior margin V-shaped, recessed; lateral carinae developed; median carina absent. Frons (Fig. 4 B) claviform, 2.85 times as long as wide. Pronotum (Figs 1C, 4A) slightly shorter than vertex. Mesonotum 1.34 times longer than pronotum and vertex combined, lateral carinae curved outwards. Forewing (Figs 1D, 4C) 2.57 times longer than wide, with 11 apical cells and six subapical cells; RP 3 branches, MP with five terminals: MP 11 , MP 12 , MP 2 , MP 3 , and MP 4 , fork MP 1 +MP 2 basad of fork MP 3 +MP 4 . Hind tibia with five lateral spines; chaetotaxy of hind tarsi 6/6. Male genitalia. Pygofer (Fig. 5A, C) symmetrical. Medioventral process rounded protruding in ventral view. Anal segment (Fig. 5A, D) asymmetrical, left lobe larger than right lobe, dorsal margin almost straight, apical margin slightly expanded downwards in lateral view; 2.44 times longer than wide in dorsal view; anal style strap-shaped, not beyond anal segment. Gonostyli (Fig. 5B, C) ventrally symmetrical; in inner lateral view, middle part slender but base and apex enlarged. Aedeagus (Fig. 5E-H) with three processes. In left side view, basal ventral margin of periandrium with a triangular laminal process, of which middle right side concaved heavily, forming two large processes, one directed cephalad, another directed caudad, basal dorsal margin of periandrium with a laminal process, of which near apex of dorsal margin recessed, apex convex, left side of margin dentate; in right side view, apical ventral margin of periandrium projecting, near apex with a long spinose process, curved upwards, directed dorsocephalad; in dorsal view, laminal process grooved, arising at left side of basal dorsal margin of periandrium, left side convex, apical right side rolling, middle part concave in a right angle, apex of periandrium with a long spinose process, slightly curved, directed cephalad; in ventral view, near apex of grooved laminal process with a long spinose process, slightly curved, directed cephalad. Endosoma slightly sclerotized, without process.
Distribution. China (Xizang) (Fig. 12). Etymology. The specific name is derived from the Latin adjective gracilispinus, referring to the one long spinose process arising from the apical right side of the ventral margin of the periandrium.
Remarks. Male genitalia of A. gracilispinus sp. nov. are similar to A. venustus Tsaur & Hsu, 1991 in appearance, but differs in: (1) basal left side of ventral margin of periandrium with a triangular laminal process, of which middle right side concaved heavily, forming two large processes (A. venustus with a spinose process in the same position); (2) near apical right side of ventral margin of periandrium with a long spinose process, slightly curved (right side of ventral margin of periandrium without spinose process in A. venustus); (3) basal dorsal margin of periandrium with a grooved laminal process (without process in A. venustus).  Description. Body length: male 5.71-6.90 mm (n = 7), female 7.78-7.90 mm (n = 2).

Andixius productus
Coloration. General color black-brown (Figs 1E, F, 6A, B). Eyes black-brown, ocelli faint yellowish brown, semitranslucent. Lateral margin of frons yellowish brown, behind eyes with an off-white spot. Antenna and vertex black-brown. Face and rostrum dark fawn. Pronotum and mesonotum black-brown. Forewing semitranslucent, generally black-brown, veins and stigma yellowish brown, tubercles black-brown; costal vein, in the middle of, behind and near claval fork with deep-brown spots. Hind tibiae light brown. Ventral abdomen brown. (Figs 1E, 6A) 1.65 times longer than wide; anterior margin slightly curved, recessed; posterior margin V-shaped, recessed; lateral carinae developed; median carina absent. Frons (Fig. 6B) claviform, 2.90 times as long as wide. Pronotum (Figs 1E, 6A) as long as vertex. Mesonotum 1.21 times longer than pronotum and vertex combined, lateral carinae curved outwards. Forewing (Figs 1F, 6C) 2.49 times longer than wide, with 13 apical cells and seven subapical cells; RP 3 branches, MP with five terminals: MP 11 , MP 12 , MP 2 , MP 3 , and MP 4 , fork MP 1 +MP 2 basad of fork MP 3 +MP 4 . Hind tibia with five lateral spines; chaetotaxy of hind tarsi 6/5. Male genitalia. Pygofer (Fig. 7A, C) symmetrical. Medioventral process rounded protruding in ventral view. Anal segment (Fig. 7A, D) long, tubular, with dorsal margin almost straight and apical margin slightly expanded downwards in lateral view; 2.67 times longer than wide in dorsal view; anal style strap-shaped, not beyond anal segment. Gonostyli (Fig. 7B, C) symmetrical ventrally, inner margin with a small spinose process near base, apex enlarged; in lateral view, near apex bending upwards. Aedeagus (Fig. 7E-H) with seven processes. In left side view, periandrium with an expanded laminal process around the left side and dorsal margin of periandrium; ventral margin of the expanded structure with two spinose processes, upper one slender, slightly curved, directed ventrocephalad, lower one small, directed ventrad; in right side view, apical ventral margin of periandrium projecting, the process expanded downwards, apex bifurcated, forming two spinose processes, the dorsal one long, another short, directed cephalad, the right side of the process with a long spinose process, bending around the periandrium, directed left-dorsocephalad, apical dorsal margin of periandrium with a long spinose process, near apex slightly curved upwards, directed dorsocephalad; in dorsal view, laminal process covering dorsal margin, middle part of periandrium with a thick, long spinose process, slightly curved, directed cephalad. Endosoma short, slightly sclerotized, without process.

Head and thorax. Vertex
Female genitalia. Tergite IX (Fig. 8A, B, D) moderately sclerotized, with a large nearly elliptical wax plate. Anal segment (Fig. 8C) rectangular, 2.43 times longer than wide in dorsal view, anal style linguiform. Gonapophysis IX (Fig. 8F) with one middle tooth; distance ratio between middle tooth to apex and length of denticulate portion is 1.98. Gonoplac (Fig. 8G) rod-like, 4.44 times longer than wide in lateral view. Posterior vagina pattern as shown in Fig. 8H.
Distribution. China (Xizang) (Fig. 12). Etymology. The specific name is derived from the Latin adjective productus, referring to the one long spinose process arising from the apical ventral margin of the periandrium.
Remarks. Male genitalia of A. productus sp. nov. are similar to A. trifurcus Zhi & Chen, 2018, but differs in: (1) periandrium with an expanded laminal process around the left side and dorsal margin of periandrium (laminal process around the left side, dorsal margin and ventral margin in A. trifurcus); (2) basal ventral margin of periandrium with laminal process, of which ventral margin with two processes (A. trifurcus  with three long spinose processes in the same position); (3) right side of ventral margin of periandrium with three spinose processes (right side of middle part of periandrium with a spinose process in A. trifurcus); (4) middle part of periandrium with a thick and long spinose process (without process in A. trifurcus). Description. Body length: male 6.56-7.20 mm (n = 10), female 7.25-8.86 mm (n = 5).

Andixius truncatus
Coloration. General color black-brown (Figs 1G, H, 9A, B). Eyes yellowish brown, ocelli faintly yellow, semitranslucent. Lateral margin of frons yellowish white, behind eyes with two brown spots. Antenna, vertex, face, and rostrum fawn. Pronotum fawn. Mesonotum yellowish brown. Forewing semitranslucent, generally black-brown; stigma fawn; veins and tubercles the same color as the wing surface; slightly below   stigma and near claval fork with an irregular, yellowish-white spot; apical half of wing light brown. Hind tibiae yellowish brown. Ventral abdomen yellowish brown.

Male genitalia. Pygofer
Female genitalia. Tergite IX (Fig. 11A, B, D) moderately sclerotized, with a large, nearly circular wax plate. Anal segment (Fig. 11C) rectangular, 1.60 times longer than wide in dorsal view, anal style linguiform. Gonapophysis IX (Fig. 11F) with one middle tooth; distance ratio between middle tooth to apex and length of denticulate portion is 2.70. Gonoplac (Fig. 11G) rod-like, 4.3 times longer than wide in lateral view. Posterior vagina pattern as shown in Fig. 11H.
Etymology. The specific name is derived from the Latin adjective truncatus, referring to the ventral margin of periandrium with a long, broad laminal process having a truncated apex. Remarks. This species can be distinguished from the other Andixius species by the following characters: forewing general black-brown, with an irregular yellowish-white spot slightly below stigma and near claval fork; ventral margin of periandrium with a long and broad laminal process, apex truncated, margin with small teeth; endosoma curving ventrally in right angle, base of dorsal margin with a long spinose process.

Discussion
The present discovery of four new species in the genus Andixius once again emphasizes the need for further study on the group based on male genitalia whenever possible (Zhi et al. 2018;Wang et al. 2020). Five species of this genus were previously described from southern China. With expanded collection efforts, our team went to Xizang Province in southwestern China, where it had not been, and there we found three of the new species described in the paper. Xizang Province has a high altitude, but it is rich in species and productive for making collections. Additionally, we found a new species with distinctive coloration in Guangxi Province.
Nine Andixius species are now known to occur in China, which can be certainly considered to be an underestimate, as the fauna is far from being well known in this interesting region. Therefore, further investigation should be considered to fill the faunistic gaps, as it is obvious that many more taxa remain to be discovered and described.
Currently the tribe Andini includes 129 species in three genera (Parandes Muir, 1925, Andes Stål, 1866, andAndixius), of which only the latter two genera and 18 species occur in China (Bourgoin 2022;Wang et al. 2022). A comparison of Andes, Andixius, and Parandes shows that species in these genera look rather similar, but these genera can be easily distinguished by the veins and fore coxa. The forewings of Andixius are without trifid branching of ScP+R and MP near the basal cell, and ScP+R (ScP+RA and RP) forming a short common stalk, while ScP, RP and MP emerge independently or very close to the basal cell in the other Andini genera. The outer edge of the apical half of the fore coxae is extended and smoothly protruding in Parandes, but the outer edge of the apical half of the fore coxae is straight and does not extend in Andes.