Nomenclatural changes in the planthopper tribe Hemisphaeriini ( Hemiptera : Fulgoromorpha : Issidae ) , with the description of a new genus and a new species

Nomenclatural changes are made in three previously described genera in the planthopper tribe Hemisphaeriini (Hemiptera: Fulgoromorpha: Issidae: Issinae), viz Gergithus Stål, 1870, Mongoliana Distant, 1909 and Hemisphaeroides Melichar, 1903. In addition, a new genus, Gnezdilovius gen. nov., with Gergithus lineatus Kato, 1933 as its type species, is described for 40 species formerly included in Gergithus, and the generic characteristics of the latter genus is revised. One new species, Gergithus frontilongus sp. nov. from China (Yunnan), is described and illustrated. One additional Gergithus species, previously misidentified as G. signatifrons Melichar, 1906 from Siberut Island, is mentioned and illustrated. Gergithus contusus Walker, 1851 is transferred to Mongoliana and Hemisphaerius atromaculatus Distant, 1916 and H. fuscoclypeatus Distant, 1916 are transferred to Hemisphaeroides. Checklists for all four genera are provided detailing the nomenclatural changes and a key to the 19 genera of Hemisphaeriini is provided. Morphological diversity and distribution of the genera are briefly discussed.


Introduction
The planthopper tribe Hemisphaeriini Melichar, 1906 was originally treated as the subfamily Hemisphaeriinae in the family Issidae Spinola, 1839, but was downgraded to a tribe of Issinae by Gnezdilov (2003).Representatives of the tribe occur throughout the Oriental region, marginally advancing into the Eastern Palaearctic region (Japan, Korea) and the Australian region (New Guinea) (Gnezdilov 2013c).
Hemisphaeriini take their name from their hemispherical body with the tegmen convex, but can also be distinguished by the indistinct venation of the tegmen and the hind wing being either single-lobed or rudimentary.Members of the tribe seem to imitate beetles, in particular ladybirds (Butler 1875;Gnezdilov 2013a).Initially, eight genera were included in the tribe Hemisphaeriini (Melichar 1906), but after over a century of research, the group is considered to be the second largest issid tribe with currently 18 genera and 176 species.
The present study has revealed several misplaced species in three genera (Gergithus Stål, 1870, Mongoliana Distant, 1909and Hemisphaeroides Melichar, 1903) and for several of those species described in Gergithus a new genus is described.A new species of Gergithus is also described.In addition, we give a key to all the genera of Hemisphaeriini.This key, together with the diagnoses for each genus, focuses mainly on external characters, as further studies are needed on the large number of genera requiring revision, with details of genitalia, in the future.Similarly, species recognition in the tribe, at present, is based mainly on colour pattern, which is distinct for all species so far studied.Although we redescribe Gergithus, it is not our intention to revise this genus at the present time, as this would require a much larger study, which it outside the scope of this paper.Instead, we provide a checklist to the species of this and three other studied genera with nomenclatural changes indicated.We also briefly discuss the distribution of the four studied genera, updating current information given for the tribe as a whole (Gnezdilov 2013c).

Diagnosis
This new species can be distinguished from other congeners by its distinct colouration (see description).

Etymology
The specific epithet is constituted from the Latin words "frons-" and "longus", referring to the elongate metope.
Colouration.Body alternating luteotestaceous and black, with large black irregular maculations.Coryphe yellow, with two black speckles.Metope flavescent on both sides, with two lateral black fasciae and central red fascia.Gena flavescent with fuscous speckle.Clypeus with postclypeus same color pattern as metope, but central fascia fulvous, anteclypeus black.Eyes pale red or rufous.Pronotum yellow with fuscous speckles in middle, lateral lobes dark brown.Mesonotum flavous, with median carina, central pits and tip fuscous.Tegmen with wide fuscous fascia from basal one third of costal margin to posterior margin, connected with large subtriangulate fuscous macula after fascia and enclosing pale yellow spot, relatively short and narrow fuscous fascia near distal one third, with series of irregular infuscate speckles at gaps of pale veins.Hind wing pale brown, veins fuscous.Legs fulvous with black stripes, tips of teeth black.Abdomen fulvous (Fig. 2A-G).Head and tHorax.Coryphe 1.3 times as wide between basal angles as median length, median carina present (Fig. 2A).Metope about 3.5 times as long in middle as width at upper margin, 2.0 times as wide at widest part below antennae as at narrowest upper margin (Fig. 2C).Mesonotum large, 2.6 times as long as pronotum in midline, approximately 2.5 times as wide at anterior margin as long in midline, median carina weak (Fig. 2A).Tegmen ovate-oblong, approximately 2.0 times as long in midline as wide at widest part; costal margin moderately convex at basal one third, apical margin acutely rounded, postclaval margin straight; postcostal cell very wide, basal cell moderately long; longitudinal veins distinctly multiramose throughout wing, with transverse veins more dense in basal third of wing (Fig. 2F).Hind wing veins net-like (Fig. 2G).Legs with fore femora roundly convex at apex, mid femora deeply concave subapically and roundly convex apically (Fig. 2E).Metatibiotarsal formula 6-11-2 (Fig. 2G).
Male genitalia.Anal tube nearly ovate in dorsal view, slightly longer than wide in midline, narrow at base, gradually widening to middle, semicircular at distal half, apical margin rounded (Fig. 3A).Paraproct digitate, 0.4 times as long as anal tube (Fig. 3A).Pygofer narrow, hind margin slightly roundly produced near dorsal margin (Fig. 3B).Dorso-lateral phallobasal lobes asymmetrical, distal part membranous, and furcated into two lobes laterally, obtusely concave dorsally; ventral phallobasal lobe large, longer than dorsolateral phallobasal lobe, right side clearly wider than left side in ventral view, apical part membranous and in form of two lobes, lobes pointed apically.Aedeagus without ventral hooks (Fig. 3D-F).Gonostyle stout, hind margin emarginate medially, anterior margin moderately convex at middle, caudo-dorsal angle rounded (Fig. 3B); capitulum of style long and thin, with a large lateral tooth and a small sharp apical process (Fig. 3C).FeMale genitalia.Anal tube peach-shaped in dorsal view, apical margin convex and with small angle at middle (Fig. 4C).Paraproct 0.3 times as long as anal tube (Fig. 4C).Gonoplac with disc relatively flat, nearly quadrate in lateral view, apical margin round and with wide membranous part, third gonoplac lobes fused at base, fork strongly sclerotized in dorsal view (Fig. 4A-B).Proximal part of posterior connective lamina of gonapophyses IX slightly protruded, distal part angularly convex near apex, median field divided into two lobes in dorsal view, and morderatly elevated medially in lateral view (Fig. 4D-E).Gonospiculum bridge moderately large, basal part nearly same length as apical part (Fig. 4D).Anterior connective laminae of gonapophysis VIII broad, with three small teeth in apical group and three keeled teeth in lateral group (Fig. 4F).Gonocoxae VIII with hind margin concave (Fig. 4F).Sternite VII with hind margin slightly widely convex at middle part (Fig. 4G).
A specimen previously identified as G. signatifrons by Baker (1927) from Siberut Island was examined (BMNH).It differs from the type specimen of G. signatifrons by 1) frons with wide blood-red longitudinal fascia medially and green fasciae laterally from upper margin to the line of antennae, lateral green fasciae curved inwards and connected by yellow transverse band, between it and clypeus also blood-red (the latter frons with red longitudinal fascia reaching metopoclypeal suture), lateral area pale yellowish, with black fascia near lateral margin below antennae; 2) clypeus blood-red medially, yellow laterally near metopoclypeal suture, and black-and-red below (the latter clypeus yellow medially and black laterally); 3) tegmen fulvous with straw yellow veins (the latter tegmen straw yellow).
All of the above characteristics show Baker's identified specimen to be distinct from G. signatifrons and probably a new species.As the specimen is a female we prefer to wait for males to become available in order to formally describe the species.

Diagnosis
Coryphe 1.5 times as wide as long, with median carina.Metope slightly longer than wide, a little widened below antenna, with or without a linear series of very small tubercles along lateral margin.Metopoclypeal suture straight.Tegmen widened at basal costal margin, veins inconspicuous, claval suture absent.Hind wing 0.7-0.8times length of tegmen, distinctly reticulate in distal part.Anal tube nearly cup-shaped.Pygofer with hind margin convex medially.Aedeagus with pair of ventral processes.Gonostyle with hind margin weakly or distinctly concave, caudo-ventral angle widely rounded.

Remarks
Fourteen species are included in Mongoliana, of which nine were examined in NWAFU.Type specimens of H. chilocorides (BMNH(E) 1705797) and H. recurrens (BMNH(E) 1705798) were also examined and their images are provided here.Although no material of Hemisphaerius contusus is available for study and the type could not be found in BMNH, the species is transferred to Mongoliana based on its original description which states: "front darker along each side is adorned with a row of little yellow tubercles" and "fore-wings widened on the border at the base near which they are slightly concave".Similarly, the specimen of this species recorded by Butler (1875) from Sula Islands could also not be found in BMNH, where other Butler specimens are deposited.(Butler, 1875).As Hemisphaerius recurrens Butler, 1875: 98,

Diagnosis
This new genus is similar to Gergithoides and Hemisphaerius.It differs from the former by the following characters: 1) coryphe nearly quadrangular (in Gergithoides coryphe nearly subtriangular); 2) metope smooth without tubercles or median carina (in Gergithoides metope with a row of tubercles and median carina); 3) genital style with hind margin slightly convex, or nearly straight, or weakly concave in middle (in Gergithoides genital style with hind margin strongly concave in middle).The new genus differs from Hemisphaerius by the following characters: 1) body medium-sized, male body length varies from 4.0 to 7.0 mm, most often length range from 5.0 to 6.5 mm (in Hemisphaerius body small, male body length varies from 3.0 to 4.6 mm); 2) hind wing well-developed, longer than half length of tegmen, usually 0. times as long as tegmen (in Hemisphaerius hind wing shorter than half length of tegmen, about 0.3 times as long as tegmen); 3) aedeagus usually with variable processes (in Hemisphaerius aedeagus without any process, phallobasal lobes with variable shape).

Etymology
Named after Dr. Vladimir M. Gnezdilov, who is a great specialist in systematic research of the family Issidae.The name is masculine.

Description
Head and tHorax.Coryphe 2.4 times as wide as long, disc depressed, without carina (Fig. 9A, F).
Male genitalia.Anal tube subtriangular, mushroom-shaped or cup-shaped.Pygofer in lateral view with hind margin roundly or spinously produced caudad.Phallobase with dorsal lobe usually reflexed at apex.Aedeagus with processes.Genital style with caudo-dorsal angle rounded, hind margin slightly convex, or nearly straight, or weakly concave in middle.Capitulum of style short, in caudal view with apical margin obtuse or acute, with small processes, lateral tooth spinule-shaped.
FeMale genitalia.Sternum VII with middle of posterior margin clearly convex or concave.Anal tube nearly ovate in dorsal view, base wider than apex.Paraproct short.Gonoplac slightly elevated in median area, border between first and second gonoplac lobes obsolete, third gonoplac lobes faintly sclerotized and pigmented.Proximal part of posterior connective lamina of gonapophyses IX convex in lateral view, median field with notch in apical part.Gonocoxa VIII nearly rectangular, dorsal margin slightly protruding in proximal part.Anterior connective lamina of gonapophysis VIII with three teeth in apical group and with two to four carinate teeth in lateral group.

Remarks
The new genus can be distinguished by the wide coryphe (more than twice as wide as long), metope almost as long as wide, clypeus small and compressed and hind wing well developed.
Forty species are here transfered to Gnezdilovius gen.nov.from Gergithus, of which we have examined type specimens of 11 species in NWAFU and specimens of several species in BMNH, where paratypes are present of G. chihpensis, G. rosticus and G. pendulus and syntypes of G. flavimaculata.All other species are known to us only by their descriptions and illustrations.Images are provided of G. lineatus (type species) based on specimens collected in Taiwan and deposited in NWAFU (Fig. 9D-F).
Checklist of species of Gnezdilovius gen.nov.

Remarks
Hemisphaeroides aeneoniger and H. lineatus are known to us from images of their type specimens (HNHM) provided here.Images of the type specimens examined of H. atromaculatus (BMNH(E) 1705790) and H. fuscoclypeatus (BMNH(E) 1705791) are also provided here.

Discussion
Most genera in the tribe Hemisphaeriini, including Gnezdilovius gen.nov., have the coryphe transverse and relatively wide (Fig. 7F) and the metope also relatively wide (Fig. 10D).Exceptions are the genera Neogergithoides (Fig. 1C), Macrodaruma (Fig. 1A) and Choutagus (Fig. 1E), where the coryphe and metope are longer than wide, and Gergithus, where the coryphe is nearly quadrate (Fig. 6A) and the metope very elongate (Fig. 6C).Gergithus also differs from all other Hemisphaeriini by the angular anteclypeus in lateral view (Fig. 6B).In addition, although G. iguchii and G. quinquemaculatus (see Che et al. 2007: figs 5-6;Chen et al. 2014: fig. 2-19A-E) have the metope slightly longer than wide and therefore fall between Gergithus and Gnezdilovius gen.nov., they do not have the angular anteclypeus found in Gergithus.On this basis, these two species are transferred to Gnezdilovius gen.nov.
The genera Gergithus and Gnezdilovius gen.nov.are both widely distributed in the Oriental region.Compared to Gergithus, which is found mainly on the Indian subcontinent and also SE Asia (Thailand, Burma, Indonesia), Gnezdilovius gen.nov. is found mainly in southern China and also SE Asia (Vietnam) and the Palaearctic region (Japan) (see Checklists).Additionally, the genus Hemisphaeroides seems to be limited in its distribution to Sri Lanka.Mongoliana is mainly distributed in southern China.
Data on the ecology of Hemisphaeriini are meagre.It has been observed that the unnamed host plant of Hemisphaerius lysanias Fennah, 1978withered when fed on in open areas in Hainan Island of China (Y.-L. Che, pers. comm. 2003).Both Hemisphaerius cattiensis Constant &Pham, 2011 andH. hippocrepis Constant &Pham, 2011 were collected in a forest (Constant & Pham 2011); H. hippocrepis occurs on forest undergrowth and forest roadsides in Vietnam (Gnezdilov 2013b), while H. interclusus was usually collected in open sunlit areas, particularly along roads and in glades, on the plant Saccharum spontaneum (L.) (Poaceae) (Gnezdilov 2013b); Rotundiforma nigrimaculata Meng, Wang & Qin, 2013 was collected in China on bamboos (Gigantochloa ligulata Gamble and Dendrocalamus sp.) by canopy fogging (Meng et al. 2013).The new species Gergithus frontilongus sp.nov.was also collected by forest canopy fogging (Zheng & Li 2013).manuscript.This study is supported by the National Natural Science Foundation of China (31372234, 30970388, 31420103911), and Fauna Sinica (2006FY120100) under the Ministry of Science and Technology of China.