Magadhaideus, a new genus of the tribe Plectoderini with the description of a new species from China (Hemiptera, Fulgoromorpha, Achilidae)

Abstract A new planthopper genus and species from China, Magadhaideus xiphos Long & Chen, gen. et sp. n. (Hemiptera: Fulgoromorpha: Achilidae: Plectoderini), is described and illustrated. A new combination, Magadhaideus cervina (Fennah, 1956), comb. n. transferred from Magadha Distant and a key to species of the new genus are also given.

Approximately four tribes, 20 genera, and 99 species of Achilidae are known in China. Plectoderini consists of 15 genera and 79 species. Almost all members of the tribe in China are distributed in the Oriental region, especially in southern China. Here, a new genus and species of the tribe from South China are described and illustrated. A new combination and a key to the species of the new genus are also provided.

Materials and methods
The morphological terminology and measurements used in this study mainly follow Chen et al. (1989) and Yang and Chang (2000). The standard terminology for hind and forewing venation follow Bourgoin et al. (2015). The methods follow Long et al. (2014). The genital segments of the examined specimens were macerated in 10% KOH and drawn from preparations in glycerine jelly using an Leica M125 stereomicroscope. The type material is deposited in the Institute of Entomology, Guizhou University, Guiyang, China (GUGC). Differential diagnosis. The new genus and Magadha are readily distinguished from other known genera in the tribe Plectoderini by mesonotum with a transverse callus on anterior third of disc (Fig. 5). The new genus differs from Magadha in: pygofer ( Fig. 11) in lateral view with dorsal margin distinctly shorter than ventral margin (dorsal margin at least as long as ventral margin in Magadha); medioventral process ( Fig. 12) broad and short, with a small sharp process lateroapically (relatively slender and without small sharp process lateroapically in Magadha); genital style ( Fig. 13) without a finger-like process from near base of dorsal margin (with a finger-like process from near base of dorsal margin in Magadha); phallobase (Figs 14-15) with apical half branched into much more and longer processes (apical half, in Magadha, at most branched into one dorsal, one ventral and two lateral lobes, all of them short).
Male genitalia. Each side of anal segment (Figs 10-11) with a strong spinous process, directed ventrally. Pygofer (Fig. 11) in lateral view with dorsal margin distinctly shorter than ventral margin, medioventral process ( Fig. 12) broad and short, lateroapical margin produced in a small sharp process. Genital style (Fig. 13) without a fingerlike process from near the base of dorsal margin, only a larger process rising from near middle of dorsal margin. Aedeagus with phallobase (Figs 14-15) sheath-shaped, asymmetrical, apical half branched into several long processes which narrowing apically and with apexes sharp. Aedeagal appendages (Figs 14-15) relatively straight, clearly exceeding the apical margin of phallobase.
Etymology. The genus name, which is masculine, is a combination of "Magadha" (name of the related genus) and "-ideus" (similar to), which indicates the new genus is similar to the genus Magadha.

Distribution. Oriental region (South China).
Key to species of Magadhaideus Long & Chen, gen. n.
Colouration. Head pale yellowish brown. Vertex (Figs 1, 3, 5) along each lateral margin with one dark brown marking at base and another one brown marking at level of anterior margin of eyes; along midline with two brow to dark brown markings apically. Triangular areolets (Figs 1, 3, 5) at lateroapical angles of head with a dark brown marking. Frons (Fig. 6) with seven dark brown markings along lateral margin, disc in middle scattered ivory-white dots between eyes. Postclypeus ivory-white, with a transverse brown band apically. Frontoclypeus (Fig. 6) dark brown, with the base and apex ivory-white. Rostrum yellowish brown, with apex brown. Genae, as in Fig. 7, with four and two transverse short dark brown stripes, respectively along anterior margin and above eyes; another two large parallel transverse stipes, one above and one beneath antennae. Eyes (Figs 1-7) generally reddish brown; ocellus (Figs 2, 4, 7) yellowish white. Antennae (Figs 2, 4, 6-7) yellowish brown. Pronotum (Figs 1, 3, 5) brown, lateral lobe with five dark brown areas along posterior margin. Mesonotum (Figs 1, 3, 5) dark brown, posterior two-thirds between lateral carinae with few scattered ivory-white dots, apical angle and areas along posterior margin between lateral carinae ivory-white, each lateral angle with a large ivory-white marking along posterior margin. Tegula (Figs 1-5) yellowish brown, along posterior margin paler. Forewing (Figs 1-4, 8) greyish white, with a broad irregular longitudinal dark brown band from base to apex of clavus, small variably sized markings scattered as in Fig. 8. Hindwing pale brown, veins brown. Legs (Figs 2, 4) ivory-white to pale yellowish brown; tibiae yellow basally, the first tarsomeres dark brown; pro-and mesofemora with a dorsal dark brown spot near base, pro-and mesotibiae with a ring dark brown spot respectively near base and in the middle; hind tibia with two ring dark brown spot near base. Abdomen dark brown.
Head and thorax. Ratio width of vertex at posterior margin to its length in midline 1.8 (Fig. 5), anterior third produced before eyes. Ratio length of frons in midline to its maximum width 1.3, ratio maximum of width to width at apex 1.9. Ratio length of postclypeus in midline to length of frons 0.5 (Fig. 6). Rostrum with ratio apical to subapical segment 1.2. Lateral lobes of pronotum with three short longitudinal carinae behind eye, ratio length in midline to length of vertex 0.8 (Fig. 5). Mesonotum (Fig.  5) in midline 5.1 times longer than pronotum, 2.3 times longer than pronotum and vertex combined. Forewing (Fig. 8) with ratio of length to maximum width 2.9, vein R with subapical cell. Hindwing (Fig. 9) with length to maximum width ratio of 2.0. Post-tibiae with a lateral spine in basal two-fifths, spinal formula 7-6-6.
Male genitalia. Anal segment in dorsal view ( Fig. 10) with ratio length to maximum width 1.2, basal margin roundly convex in middle, apical margin slightly convex  to subtruncate, anal style not exceeding apical margin of anal segment; in lateral view (Fig. 11) apex of anal segment bent ventrally, apical margin roundly convex, lateral margin near middle with a strong spinous process, directed ventrally. Pygofer in lateral view ( Fig. 11) with posterior margin strongly sinuate, medioventral process (Fig. 12) short and broad, with two small lateroapical processes, directed outward, apical margin truncate. Genital style (Fig. 13) relatively narrow and long with apical margin roundly convex, a large and broad process, with apical margin sinuate, rising from middle of dorsal margin. Aedeagus (Figs 14-15) asymmetrical, phallobase with apical half branched into seven long processes which narrowing apically, acute at apexes; among them, two lateral processes with apexes bent, directed inwards. Phallic appendages straight, xiphoid, distinctly exceeding apical margin of phallobase.
Female genitalia. Seventh abdominal sternum with anterior and posterior margins parallel, posterior margin truncate or slightly concave (Fig. 16). Anal segment (Figs 17-18) in dorsal view suborbicular, apical margin incised in the middle, basal margin M-shaped approximatively, with finger-like process in the middle; apex of anal stylet reaching or slightly exceeding apex of anal segment. First valvula with five spines (Fig. 19). Second valvula with two lateral lobes incompletely symmetrical, narrowing and sharp apically, directed postero-ventrally (Fig. 20). Third valvula with outer surface shagreen (Figs 16, 18); in lateral view (Fig. 18) apical margin sinuate, with an angulate process ventrally, directed inwards. Remarks. This new species differs from Magadhaideus cervina (Fennah, 1956) comb. n. by: forewing with a dark brown stripe from base to apex of clavus (without stripe in cervina); medioventral process of pygofer with two small lateroapical processes, directed outward (directed inward in cervina); genital style with dorsal process almost not branched into lobes (distinctly branched into three lobes in cervina).

Discussion
On the basis of the characteristics of the vertex being at least two-thirds as wide as the pronotum and the post-tibiae with one spine characteristically present, Magadhaideus gen. n. is attributed to the tribe Plectoderini, following the tribal definition of Emeljanov (1992). On the basis of the peculiar characteristic of the mesonotum with a transverse callus on the anterior third of the disc, Magadha is clearly distinguished from other genera of Plectoderini, following the generic definition of Fennah (1950). Although the new genus also has the transverse callus, its male genitalia distinctly differs from that of Magadha. According to the descriptions and illustrations of Magadha cervina Fennah, 1956(Fennah 1956 fig. 15: A-E), it is here attributed to the new genus.
The members of Plectoderini are found in seven zoogeographic regions of the world (Bourgoin 2017). Here, the new genus (Fig. 21) is distributed in the Oriental region of southern China. The adults of Plectoderini feed on the sap of trees and shrubs and the nymphs on fungi (O' Brien 1971). However, more precise ecological records for most members of the tribe, including the hosts for Magadhaideus gen. n., have not yet been documented.