Species Diversity in the Leafhopper Genus Batracomorphus Lewis (Hemiptera: Cicadellidae: Iassinae) from Qinling Mountain in Shaanxi

Simple Summary Qinling Mountain is one of the global biodiversity hotspots, dividing northern temperate zones from subtropical zones. However, no species of Batracomorphus was previously recorded from Qinling Mountain in Shaanxi. We collected some specimens of Batracomorphus from this site and classified these into nine species based on a comparative morphological study, including one new species and one new synonym. The results of this study revealed species diversity and distributions of Batracomorphus. Abstract The genus Batracomorphus Lewis is the third largest leafhopper genus in the world, with its greatest diversity in the Oriental region. Here, nine species of Batracomorphus, including one new species, are recorded from Shaanxi Province, China, for the first time: B. allionii (Turton), B. clavatus Cai and Shen, B. fletcheri Hu and Dai sp. nov., B. geminatus (Li and Wang), B. juno Knight, B. lateprocessus Li and Wang, B. lunatus Cai and He, B. subfuscus (Li and Wang) and B. pandarus Knight. Among them, B. juno Knight is recorded from China for the first time. One new synonym is revealed: B. nigromarginattus Cai and Shen, 1999 is a junior synonym of B. subfuscus (Li and Wang, 1993). All taxa are described, and photographs of male genitalia are given based on observations of specimens from Qinling Mountain in Shaanxi of China. A key to the species found in Qinling Mountain of Shaanxi is also provided.


Introduction
The Cicadellidae is the largest family in the Hemiptera with more than 23,000 described species distributed worldwide. Iassinae is one of 25 subfamilies of leafhoppers and comprises more than 2000 species and 154 genera currently placed in twelve tribes [1][2][3][4][5]. Iassines are mostly arboreal and are distributed worldwide, but most of the tribes and genera are restricted to a single biogeographic realm.
The widespread Old-World genus Batracomorphus, originally established by Lewis (1834) [6], is the third largest leafhopper genus in the world and contains ca. 360 species, distributed throughout the temperate and tropical regions of the Eastern Hemisphere. Species of Batracomorphus are mainly arboreal, although some also occur on shrubs, herbaceous plants, and grasses [7,8]. Some species of this group cause injury to economically important trees, such as willow, apples, pears, and other fruit trees, as well as to alfalfa, rice and other crops [9]. In China, Batracomorphus allionii damages economic trees [10] and feeds on bamboo [11], and B. pandarus injures wine grapes [11]. Elsewhere, Batracomorphus angustatus (Osborn) is a vector of the phytoplasmas which cause tomato big bud and potato purple top wilt disease [12]. Batracomorphus angustatus is a possible vector of Australian grapevine yellows [13].
Acojassus Evans, 1972: 656 [16]. Type species: Acojassus montanus Evans, 1972 [16]. Medium-sized (4-8 mm) leafhoppers with overall usually pale green (fading to yellow in dry specimens), rarely with brown markings. Head slightly narrower (rarely equal to or wider) than pronotum. Vertex in dorsal aspect short, transversely striate; length uniform, rarely slightly longer medially; anterior margin broadly rounded in dorsal aspect; in lateral aspect slightly declivous in line with pronotum, continuously curved to face or with dorsal area flattened. Face short, broad; maxillary plates wide, lateral margins sinuate. Lora widely separated from margin. Frontoclypeus broad, approximately circular in outline, laterofrontal sutures terminating just above antennal ledges. Clypellus distinct, short, broad, sides parallel. Antennae near ventral margin of eyes. Antennal ledges prominent, transverse or slightly oblique, extending onto frontoclypeus. Antennal pits deep. Ocelli distinct, near anterior margin of face, each approximately midway between midline and corresponding eye. Pronotum longer than vertex, slightly declivous anteriorly, increasing in width posteriorly, rarely parallel-sided; lateral margins long, strongly carinate; posterior margin shallowly concave; transversely striate. Scutellum long. Forewings long, exceeding abdomen, semi-coriaceous with appendix and first apical cell membranous, weakly punctate, rarely with small tubercles; appendix wide; vein separating appendix and first apical cell complete throughout its length; three subapical cells, closed basally. Setal formula of hind femur III: 2:1:1.
Male genitalia with pygophore longer than height, emarginate dorsally to near milength; lateral lobes broadly or narrowly rounded posteriorly, short spine-like setae scattered over posterior half; elongate, arched, posteriorly directed process arising near base of ventral margin, rarely absent. Tenth segment membranous. Valve small, fused to pygophore. Sub-genital plates slender, triangular, extending to apex of pygophore, with short basal stem, the latter sometimes small or obscure; long hair-like setae usually arranged as a dorsolateral group at base, a short uniseriate row on dorsolateral margin and a multiseriate row on ventral margin extending also over medial surface of plate, the dorsolateral or ventral rows sometimes absent, plates sometimes densely setose. Eighth sternite longer than preceding ones and covering basal half of genital capsule. Style with apical process elongate, terminating in a small dorsally directed hook, a ventral subapical expansion sometimes present; lateral lobe well-developed; basal arm very short. Connective Y-shaped with anterior arms linked to each other dorsally and ventrally by plate-like extensions; articulated to aedeagus. Aedeagus simple, shaft directed dorsally, with or without process; gonopore usually long and extending over distal half of posterior margin of shaft, sometimes short; a longitudinal incision on anterior margin of shaft approximately same length as gonopore usually present.
Distribution. Batracomorphus occurs in all geographical regions, with the exception of the New World.
Notes. The genus Batracomorphus, established with Batracomorphus irroratus Lewis as the type species, is distributed throughout the temperate and tropical regions of the Eastern Hemisphere. Recently, Batracomorphus was placed in the monobasic tribe Batracomorphini. This tribe was placed as sister to Hyalojassini with strong branch support based on phylogenetic analysis, combining morphological and molecular data from multiple gene regions [5]. In that study, the newly established tribe was defined mainly on external characters: small to medium-sized, pale green or stramineous leafhoppers; head rounded in profile, without distinctly delimited crown; forewing appendix well-developed but not extended around wing apex; hindwing veins R4 + 5 and M1 + 2 completely confluent distally; male pygofer with stout setae scattered over distal half, ventral process slender, elongate, apex not falcate; sub-genital plate not completely concealed by pregenital sternite, extended nearly as far posterad as pygofer apex; female first valvulae with dorsal sculpturing strigate; second valvulae with two to three widely spaced dorsal teeth.
In external morphology, most species of Batracomorphus are remarkably uniform, differing only slightly in overall size and proportions. Thus, they are difficult to identify without studying the male genitalia. A comparative study of the male genitalia of available specimens revealed considerable variation in several structures, including pygophore processes, style and aedeagus, and such variation has supported separation of most of the known species. These structures were used previously to elucidate the natural relationships of the species in the Oriental and Australian regions and were divided into five informal groups [8]. All features listed above may need to be taken into consideration for accurate classification, and other evidence may be needed to further confirm species limits.
Batracomorphus Lewis appears to be of relatively recent origin with a broad ancestral range, arising between middle Eocene and late Miocene [5,14]. Now, it is one of largest genera in Cicadellidae with over 360 species, and predominantly occurs in the Oriental region [8]. Its major diversification has taken place in the tropics, where 121 species have been described from the Afrotropical region [14]. Recently, a number of additional species have subsequently been added to this genus. More general investigations and more taxonomic sampling are needed to reveal the biodiversity from constituent areas in the Oriental region.

Overview of Species Identification, Distribution
Nine species of the leafhopper genus Batracomorphus from Qinling, Shaanxi are recorded based on comparative morphological study, including one new species and one new synonym as shown in the following section. (Figures 1-13).  In the following section, detailed information on the collected specimens is report with comments, and the descriptions of nine species are provided.        Aedeagus with shaft slender, directed dorsally with apical one-fourth curved antero dorsally, tapering to apex in both lateral and posterior aspect, anterolateral margins produced flange-like apically and turned anteriorly. Gonopore extending approximately two-fifths length of shaft, apical incision approximately 3/4 length of gonopore. Remarks. This species was described by Knight in 1983 [8], based on three male specimens from Borneo. It is very similar to B. romulus Knight [8] but can be differentiated   Colour pale yellowish. Forewing with appendix piceous. Pygofer side longer than height, tapering to acute apex, with many macrosetae near posterior margin, inner process moderately slender, extended straight posterodorsad to mid-length then bent posteroventrad, ventral margin serrate near apex, apex acuminate. Style thin, abruptly narrowed and sinuate in distal 1/4, apex hooked ventromesad. Connective stem gradually expanded posteriorly. Sub-genital plate thin, with many long fine  Remarks. This species was described based on one male and two female specimens deposited in the collection of Guizhou University. The illustrations given by Li and Wang (1993) [18] were misleading. Dr. J.C. Xing checked the type specimen and confirmed that the male genitalia illustrated here agree with the male genitalia of the holotype. B. nigromarginattus was described from Henan by Cai and Shen (1999) [48]. Based on the descriptions and illustrations provided by Li   we propose the synonymy of these two taxa. This species is similar to B. allionii (Turton) but can be distinguished by the forewings with a dark brown appendix, the aedeagal shaft curved dorsally near the apex, and the appendage of pygofer taper to apex. Colour yellowish green. Forewings with distinctive fine setae and punctation black; appendix at base fuscous.

Species Description
Pygofer side round apically, with many macrosetae near posterior margin, inner process slender, sinuate posteriorly, apex acute, curved posterodorsally, ventral margin apex. Sub-genital plate semi-membranous, elongate, with stem and lateral lobe basally; a group of long hair-like setae on dorsolateral margin of lobe; a short uniseriate row of long hair-like setae on dorsolateral margin near mid-length; a multiseriate row of long hairlike setae on ventral margin near mid-length, extending also over medial surface of plate. Aedeagus simple, strongly enlarged and expanded ventrally at base; shaft relatively short, slender, arising from dorsal part of atrium, evenly recurved anteriorly, tapering to apex; evenly tapered in posterior aspect; gonopore extending approximately 1/2 length of shaft, apical incision very short. Distribution. China (Shaanxi, Zhejiang, Hunan) Remarks. This species was described based on a male and a female specimen from Yunnan. Unfortunately, the illustrations given by Li and Wang (2003) [19] were misleading. Dr. Xing (personal communication) confirmed that the male genitalia illustrated here agree with the male genitalia of the holotype. This species resembles B. thetis Knight [8], but can be distinguished by the slender aedeagal shaft with the apex slightly curved anteriorly, and an apical process of style expanding over the distal half; the apical incision is very short.  Colour stramineous. Forewing with appendix at base fuscous. Pygophore protruding apically, distributed with sparsely short and thick bristles subapically, inner process slender, evenly arcuate, curving medially, tapering gradually to acute apex, ventral margin serrate near apex. Sub-genital plate semi-membranous, elongate, with uniseriate row of long hair-like setae on dorsolateral margin near mid-length  Distribution. China (Shaanxi, Henan).
Remarks. This species was described by Shen and Cai [21] based on a male and a female specimen from Henan. It is similar to B. iulus Knight [8]   ventral margin, portion of the process distad of spur usually longer than spur. Style slightly expanded at mid-length, tapering gradually to short acute ventromesally hooked apex, with small expansion subapically on dorsal margin. Sub-genital plate semi-membranous, elongate, with stem and lateral lobe basally; a group of long hair-like setae on dorsolateral margin of lobe; a short uniseriate row of long hair-like setae on dorsolateral margin near mid-length; a multiseriate row of long hair-like setae on ventral margin near mid-length. Aedeagus with shaft in lateral aspect slender, elongate, directed dorsally with apical third curving anterodorsally, in ventral view slightly wider; lateral margin over distal one-seventh expanded as lamellate triangular flange; gonopore extending to just basad of mid-length of shaft; apical incision short.  Remarks: B. lunatus was described by Cai and He [42] from Zhejiang, China. This species is similar to B. peteos Knight [8] but differs from the latter in having the style and pygofer processes with subapical expansions, and the aedeagus with lamellate angular flanges apically. This species also resembles B. romulus Knight [8] but is distinguished by the aedeagus with a lamellate angular flange apically, and the style and pygofer processes with subapical expansions.

1.
Forewing without fine hair and punctation (Figures 2 and 4A,B)  Aedeagus base strongly enlarged and expanded ventrally ( Figure 10D), pygophore process nearly straight, thin ( Figure 10A,B)  In the following section, detailed information on the collected specimens is reported with comments, and the descriptions of nine species are provided. Pale stramineous to pale yellowish green, with fuscous spot at base of appendix. Pygophore narrowed to round caudal margin, inner process slender and straight through most of length, abruptly curved ventrally near apex, apex shallowly concave. Subgenital plate semi-membranous, elongate, with a multiseriate row of long hair-like setae on ventral margin near mid-length and a short uniseriate row of long hair-like setae on dorsolateral margin near mid-length. Style narrowed near middle, slightly expanded distally with mesal margin serrate, apex hook-like. Aedeagus slender, dorsoatrium relatively long, approximately 2/3 length of aedeagus shaft, shaft with conspicuous lamellate lateral expansion subapically and lamellate extensions on anterior margin; gonopore extending approximately one-third length of shaft; apical incision short, approximately one-third length of gonopore. Remarks. B. allionii is mainly distributed in Europe. This species was originally described by Fabricius [27] from Italy as Cicada prasina and transferred to Batracomorphus by Lindberg [32]. Metcalf [36] found this name was a homonym and proposed the replacement name fabricii. Later, Metcalf [38] synonymized B. fabricii with B. allionii (Turton, 1802). Recently, two Chinese species, B. dentatus (Kuoh) and B. trunctus (Li and Wang) was considered to be a synonym with B. allionii (Turton) by Cai and Shen [21]. Based on the description and the illustrations of male genitilia provided by Ribaut [35] and Ossiannilsson [33], Chinese specimens we examined should be B. allionii.

Species Description
Hosts. Cytisus scoparius and Genista tinctoria, and perhaps additional species of woody Fabaceae, and bamboo.  [11].
Colour pale stramineous. Forewing with appendix at base piceous. Pygofer side tapering gradually to blunt rounded margin, with many macrosetae near posterior margin, inner process moderately slender, arched near base then straight to ventromedially bent and tapered apex. Sub-genital plates semi-membranous, elongate, with a multiseriate row of long hair-like setae on ventral margin near mid-length and a short uniseriate row of long hair-like setae on dorsolateral margin near mid-length. Style simple, sinuate, width nearly uniform throughout length; apex hooked anterolaterally. Aedeagus with shaft slender, directed dorsally with apical one-fourth curved antero dorsally, tapering to apex in both lateral and posterior aspect, anterolateral margins produced flange-like apically and turned anteriorly. Gonopore extending approximately two-fifths length of shaft, apical incision approximately 3/4 length of gonopore. Remarks. This species was described by Knight in 1983 [8], based on three male specimens from Borneo. It is very similar to B. romulus Knight [8] but can be differentiated from the latter by the more robust aedeagal shaft and lack of the lateral flange-like expansion at the base of the shaft. Colour pale yellowish. Forewing with appendix piceous. Pygofer side longer than height, tapering to acute apex, with many macrosetae near posterior margin, inner process moderately slender, extended straight posterodorsad to mid-length then bent posteroventrad, ventral margin serrate near apex, apex acuminate. Style thin, abruptly narrowed and sinuate in distal 1/4, apex hooked ventromesad. Connective stem gradually expanded posteriorly. Sub-genital plate thin, with many long fine setae along both margins. Aedeagus simple, shaft elongate, slender in lateral aspect, curving anterodorsally, laterally expanded in distal 1/3 subapically in posterior aspect, apical incision very short.
Material Remarks. This species was described based on one male and two female specimens deposited in the collection of Guizhou University. The illustrations given by Li and Wang (1993) [18] were misleading. Dr. J.C. Xing checked the type specimen and confirmed that the male genitalia illustrated here agree with the male genitalia of the holotype. B. nigromarginattus was described from Henan by Cai and Shen (1999) [48]. Based on the descriptions and illustrations provided by Li and Wang (1993) [18] and Cai and Shen (1999) [48], we propose the synonymy of these two taxa. This species is similar to B. allionii (Turton) but can be distinguished by the forewings with a dark brown appendix, the aedeagal shaft curved dorsally near the apex, and the appendage of pygofer taper to apex. Colour yellowish green. Forewings with distinctive fine setae and punctation black; appendix at base fuscous.
Pygofer side round apically, with many macrosetae near posterior margin, inner process slender, sinuate posteriorly, apex acute, curved posterodorsally, ventral margin acutely ridged subapically, sometimes with spur-like process, variable in relative length of process distad of spur. Sub-genital plate semi-membranous, elongate, with a multiseriate row of long hair-like setae on ventral margin near mid-length. Styles with apical process increasing gradually in width posteriorly, abruptly narrowed subapically to short acute dorsally hooked apex, ventral margin of subapical constriction acutely ridged. Aedeagus simple; shaft directed dorsally, tapered to apex over distal half; gonopore extending approximately two-thirds length of shaft; apical incision slightly shorter than gonopore, extending to near mid-length of shaft. Notes: This species was described based on a series of specimens from Philippines, Borneo, and West Malaysia. It is similar to B. spadix Shen et Cai [21] but differs from the latter in having the style slightly curved in ventral aspect with apex hooked directed dorsally, and the pygophore processes slender and sinuate with the apex acute and directed dorsally, and exterior rim serrated. Colour yellowish green. Forewings with distinctive fine setae and punctation black; appendix at base fuscous.
Pygophore protruding apically, with many macrosetae near caudal margin, inner process slender and evenly arched through most of length, broadened and recurved postero-dorsally near apex, apex foot-like with short, slender ventral heel and curved, tapered toe. Style thin near base slightly expanded beyond mid-length, unevenly tapered to dorsolaterally hooked apex. Sub-genital plate transparent and thin, long, with many long bristles on each margin. Aedeagus with shaft slender, elongate, directed dorsad and curved slightly anterad near apex, apex slightly narrowed in lateral view; parallel sided through most of length in posterior view; gonopore and apical incision relatively long, extending over one half of shaft.
Material examined. Holotype: ♂, Shaanxi, Ningshan, Huoditang Forest Station, 18.vii.2018, Sun Qihan (NWAFU) (Figure 1) Color stramineous. Forewings with distinctive fine setae and punctation black. Pygophore round apically, with many macrosetae near posterior margin, inner process moderately slender and nearly straight, slightly expanded in apical half, hardly reaching pygofer apex, tapering gradually to slender acute apex in lateral aspect. Style expanded over distal half and then tapering and gradually curved to upturned finger-like apex. Sub-genital plate semi-membranous, elongate, with stem and lateral lobe basally; a group of long hair-like setae on dorsolateral margin of lobe; a short uniseriate row of long hair-like setae on dorsolateral margin near mid-length; a multiseriate row of long hair-like setae on ventral margin near mid-length, extending also over medial surface of plate. Aedeagus simple, strongly enlarged and expanded ventrally at base; shaft relatively short, slender, arising from dorsal part of atrium, evenly recurved anteriorly, tapering to apex; evenly tapered in posterior aspect; gonopore extending approximately 1/2 length of shaft, apical incision very short. Distribution. China (Shaanxi, Zhejiang, Hunan) Remarks. This species was described based on a male and a female specimen from Yunnan. Unfortunately, the illustrations given by Li and Wang (2003) [19] were misleading. Dr. Xing (personal communication) confirmed that the male genitalia illustrated here agree with the male genitalia of the holotype. This species resembles B. thetis Knight [8], but can be distinguished by the slender aedeagal shaft with the apex slightly curved anteriorly, and an apical process of style expanding over the distal half; the apical incision is very short. Colour stramineous. Forewing with appendix at base fuscous. Pygophore protruding apically, distributed with sparsely short and thick bristles subapically, inner process slender, evenly arcuate, curving medially, tapering gradually to acute apex, ventral margin serrate near apex. Sub-genital plate semi-membranous, elongate, with uniseriate row of long hair-like setae on dorsolateral margin near midlength and a multiseriate row of long hair-like setae on ventral margin near mid-length. Style long, slender, tapering gradually to acute dorsomedially hooked apex. Aedeagus with shaft short, evenly wide through most of length in lateral aspect, broadly rounded apically, directed posteriorly, and curved dorsally; in posterior aspect with lateral mar gins near mid-length expanded forming lamellate triangular flange; gonopore subapical at ventral margin. Distribution. China (Shaanxi, Henan).
Remarks. This species was described by Shen and Cai [21] based on a male and a female specimen from Henan. It is similar to B. iulus Knight [8] [46].
Description. Male 5.5-6.0 mm long, 1.0 mm wide across eyes, 1.9 mm wide across hind margin of pronotum.
Colour stramineous. Forewings with distinctive fine setae and punctation black; appendix at base fuscous.
Pygophore narrowed gradually to rounded caudal margin, with many macrosetae near posterior margin, inner process slender, elongate, arched dorsad at base, then straight through most of length to slightly decurved apex; with small subapical spur on ventral margin, portion of the process distad of spur usually longer than spur. Style slightly expanded at mid-length, tapering gradually to short acute ventromesally hooked apex, with small expansion subapically on dorsal margin. Sub-genital plate semi-membranous, elongate, with stem and lateral lobe basally; a group of long hair-like setae on dorsolateral margin of lobe; a short uniseriate row of long hair-like setae on dorsolateral margin near mid-length; a multiseriate row of long hair-like setae on ventral margin near mid-length. Aedeagus with shaft in lateral aspect slender, elongate, directed dorsally with apical third curving anterodorsally, in ventral view slightly wider; lateral margin over distal oneseventh expanded as lamellate triangular flange; gonopore extending to just basad of mid-length of shaft; apical incision short. Distribution: China (Guizhou, Shaanxi, Zhejiang). Remarks: B. lunatus was described by Cai and He [42] from Zhejiang, China. This species is similar to B. peteos Knight [8] but differs from the latter in having the style and pygofer processes with subapical expansions, and the aedeagus with lamellate angular flanges apically. This species also resembles B. romulus Knight [8] but is distinguished by the aedeagus with a lamellate angular flange apically, and the style and pygofer processes with subapical expansions. Color yellowish green. Forewing with appendix at base fuscous. Pygophore narrowing gradually to rounded caudal margin, with many macrosetae near posterior margin, inner process elongate, slender, arched throughout length, apex acute. Sub-genital plate transparent and thin, long, with fewer and short bristles born on each of side margins. Style with approximately uniform width to mid-length, then slightly widened to arched distal half, terminating in acute dorsally directed apex and with elongate ventrally directed projection subapically on ventral margin. Aedeagus with shaft slender, elongate, directed posteriorly and turning posteroventrally at sub-apex,