Two New Species of Betacixius Matsumura, 1914 (Hemiptera: Fulgoromorpha: Cixiidae) from Southwestern China, with an Updated Checklist and Key to Species

Simple Summary Betacixius Matsumura, 1914 is a small genus of cixiid planthoppers distributed throughout China, Japan and Vietnam. Despite its rich biodiversity in Southwest China, Betacixius has not been taxonomically well studied in this region. Here, two new species, Betacixius gongshanensis sp. nov. from Yunan Province and B. guizhouensis sp. nov. from Guizhou Province, are described, giving the genus 27 species in total. We believe that the discovery in this study will contribute to further studies on the classification and phylogeny of Cixiidae. Abstract In this study, two new species of genus Betacixius Matsumura, 1914 (Fulgoromorpha, Cixiidae), Betacixius gongshanensis sp. nov. from Yunnan Province and B. guizhouensis sp. nov. from Guizhou Province, are described and illustrated. An updated checklist and identification key to known species of the genus Betacixius are provided.


Introduction
The cixiid planthopper genus , in the tribe Semonini (Hemiptera: Cixiidae: Cixiinae), currently consists of 25 species and two subspecies distributed throughout China, Japan and Vietnam [1]. Following our previous works [2,3], we aim to revise the species from Southwest China in the present study. The specimens from Guizhou and Yunnan provinces brought to our attention another two new species, Betacixius gongshanensis and B. guizhouensis, which are described and illustrated here. The total number of Betacixius species is thus increased to 27, with 25 occurring in China. An updated checklist and identification key of Betacixius are given.
Coloration. General color yellowish brown ( Figure 1A-D). Eyes dark brown, ocelli dark red. Vertex yellowish to dark brown, pronotum and mesonotum brown. Frons generally yellowish brown, with a whitish yellow marking at areas of level below median ocellus, above frontoclypeal suture, extending to antennae, lateral part of pronotum and base of forewing. Postclypeus yellow to blackish brown and anteclypeus blackish brown. Rostrum generally yellowish brown. Forewing semi-translucent, clavus with a blackish brown spot on apical third, stigma blackish brown. Hind tibiae yellowish brown and abdominal sternites blackish brown.
Male genitalia. Pygofer ( Figure 1F,G) symmetrical, dorsal margin concave and Ushaped ventrally, widening towards apex; in lateral view, lateral lobes arched and extended caudally. Medioventral process triangular in ventral view. Anal segment ( Figure 1F,H) tubular and symmetrical, with apical lobes ventrally round in lateral view, 1.9 times longer than wide in dorsal view; anal style strap-like, not beyond anal segment. Gonostyli ( Figure 1F,G,I) symmetrical in ventral view, in inner lateral view, apical part extended in a triangle. Aedeagus ( Figure 1J-M) with three processes. Left and right sides of the periandrium apically with a medium-sized spinose process, both spinose processes curved downwards, with the middle part closer to each other under the periandrium and the apexes directed outwards respectively. Endosoma (=flagellum) slender, structure simple, apex with a small hook-like spinose process, ventrocaudally directed. apexes directed outwards respectively. Endosoma (=flagellum) slender, structure simple, apex with a small hook-like spinose process, ventrocaudally directed.  VIII ( Figure 2E) elongated, and slightly curved upwards. Gonapophysis IX ( Figure 2F) with two middle teeth, with a distance ratio, between distal middle tooth to apex and length of denticulate portion, of 2.4. Gonoplac ( Figure 2G) rod-like, 3.9 times longer than wide in lateral view. Posterior vagina pattern, as shown in Figure 2H,I is elongated. All sclerites located on the basal half of posterior vagina. Ventral wall with several round and oval sclerites dispersed, with a large one on the left side and the others being relatively small; dorsal wall with oval and round sclerites that larger than the ones on ventral wall.  Female genitalia. Tergite IX (Figure 2A,B,D) moderately sclerotized, with a large wax plate, nearly oval, dorsal and ventral margins concave. Anal segment (Figure 2A,C) rectangular, 1.2 times wider than long in dorsal view, anal style strap-like. Gonapophysis VIII ( Figure 2E) elongated, and slightly curved upwards. Gonapophysis IX ( Figure 2F) with two middle teeth, with a distance ratio, between distal middle tooth to apex and length of denticulate portion, of 2.4. Gonoplac ( Figure 2G) rod-like, 3.9 times longer than wide in lateral view. Posterior vagina pattern, as shown in Figure 2H,I is elongated. All sclerites located on the basal half of posterior vagina. Ventral wall with several round and oval sclerites dispersed, with a large one on the left side and the others being relatively small; dorsal wall with oval and round sclerites that larger than the ones on ventral wall.
Etymology. The species name is derived from Gongshan County, Yunan Province, where the type locality is located. curves downwards (the same spinose process is directed upwards in B. maguanensis); (2) the apical lobes of the anal segment are round in the lateral view (in B. maguanensis, the apical lobes of the anal segment are pointed in the lateral view); and (3) the mesonotum is brown (while the latter is black).
Diagnosis. This species can be distinguished from other species of the same genus by the following combination of characteristics: the pronotum and mesonotum are both brown; the clavus of the forewing has a blackish brown spot on the apical third; the anal segment is symmetrical, with the apical lobes ventrally round in the lateral view; the aedeagus with the apexes of the left and right sides of the periandrium, each with a medium-sized spinose process, curves downwards, with the middle parts closer to each other under the periandrium and the apexes directed outwards, respectively; and finally the apex of the endosoma has a small hook-like spinose process. Coloration. General color blackish brown ( Figure 3A-D). Eyes dark brown, ocelli dark red. Vertex yellowish brown, pronotum and mesonotum black. Frons generally yellowish brown, with a whitish yellow marking below the median ocellus, above frontoclypeal suture extending to antennae, lateral parts of pronotum and base of the forewing. Postclypeus yellow to blackish brown and anteclypeus blackish brown. Rostrum generally brown. Forewing semi-translucent, clavus with a blackish brown spot on apical third, stigma blackish brown. Hind tibiae brown and abdominal sternites blackish brown.
Head and thorax. Vertex ( Figure 3A,C) broad, 1.9 times wider than long; anterior margin arched convexly, posterior margin arched concavely, median carina distinct and complete. Frons ( Figure 3D) with a length nearly equal to its width, median carina indistinct, extending from slightly above level of lateral ocelli towards median ocellus. Clypeus with median carina distinct and elevated throughout. Pronotum ( Figure 3C) 1.5 times longer than vertex, and the posterior margin concave at an obtuse angle. Mesonotum 1.5 times longer than pronotum and vertex combined. Forewing ( Figure 3E) 2.5 times longer than wide, with nine apical and five subapical cells; fork Sc+RP slightly distad of fork CuA 1 +CuA 2 ; first crossvein r-m slightly distad of fork MP; RP two branches, MP with four terminals, MP 1 , MP 2 , MP 3 , and MP 4 , fork MP 1 +MP 2 distad of fork MP 3 +MP 4 . Hind tibia with three lateral spines, metatibiotarsal formula: 6/7/7, second segment of hind tarsus with three platellae.
Male genitalia. Pygofer ( Figure 3F,G) symmetrical, with dorsal margin concave and U-shaped ventrally and widened towards apex; in lateral view, lateral lobes arch extend caudally. Medioventral process arc in ventral view. Anal segment ( Figure 3F,H) long, tubular, and symmetrical, with apical lobes ventrally pointed in lateral view, and 2.3 times longer than wide in dorsal view; anal style finger-like, and not beyond the anal segment. Gonostyli ( Figure 3F,G, I) symmetrical in ventral view; in inner lateral view, apical part extended and triangular. Aedeagus ( Figure 3J-M) with three processes. Right side of periandrium with a long spinose process at the apex, which strongly curved upwards, and the apex dorsally directed; spinose process on left side of periandrium being the longest, gently curving from left to right over periandrium, with apex exceeding right lateral margin of periandrium and being right-ventrocephalically directed. Endosoma (=flagellum) slender, structure simple, and the apex with a small hook-like spinose process.   middle teeth, at a distance ratio, between distal middle tooth to apex and length of denticulate portion, of 2.3. Gonoplac ( Figure 4G) rod-like, 3.7 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 4H,I, elongated. Ventral wall of posterior vagina with two large oval sclerites on the right: the basal one with the left 1/4 cracked and the other one with the right basal 1/2 bent towards the dorsal wall. Dorsal wall with several small, round, oval, and irregular sclerites arranged longitudinally in the middle area.  Female genitalia. Tergite IX ( Figure 4A,B,D) moderately sclerotized, with a large oval wax plate, dorsal and ventral margins concave. Anal segment ( Figure 4C) rectangular, 1.4 times wider than long in dorsal view, with anal style finger-like. Gonapophysis VIII ( Figure 4E) elongated, and slightly curved upwards. Gonapophysis IX ( Figure 4F) with two middle teeth, at a distance ratio, between distal middle tooth to apex and length of denticulate portion, of 2.3. Gonoplac ( Figure 4G) rod-like, 3.7 times longer than wide in lateral view. Posterior vagina pattern as shown in Figure 4H,I, elongated. Ventral wall of posterior vagina with two large oval sclerites on the right: the basal one with the left 1/4 cracked and the other one with the right basal 1/2 bent towards the dorsal wall. Dorsal wall with several small, round, oval, and irregular sclerites arranged longitudinally in the middle area.
Etymology. The species name is derived from Guizhou Province, where the type locality is located.

Distribution. China: Guizhou.
Remarks. The male genitalia of Betacixius guizhouensis Zhi & Chen sp. nov. is similar to that of B. rinkihonis Matsumura, 1914, but differs in: (1) the apical lobes of the anal segment are pointed in the lateral view (in B. rinkihonis, the apical lobes of the anal segment are round in the lateral view); (2) the endosoma has a small hook-like spinose process apically (the latter does not have this spinose process); and (3) the anal segment is 2.3 times longer than it is wide (the anal segment is only 1.5 times longer than it is wide in B. rinkihonis).
Diagnosis. This species can be distinguished from other species of the genus by the following combination of characteristics: the pronotum and mesonotum are black; the clavus of the forewing has a blackish brown spot on the apical third; the anal segment is symmetrical, with the apical lobes ventrally pointed in the lateral view; the apexes of the left and right sides of the periandrium each have a long spinose process, with the right spinose process being strongly curved upwards, and the left one being straighter and gently curving from left to right over the periandrium, and the apex exceeding the right lateral margin of the periandrium; and the apex of endosoma has a small hook-like spinose process.