Youtuus, a new bamboo-feeding genus of the tribe Augilini with two new species from China (Hemiptera, Fulgoromorpha, Caliscelidae)

Abstract A new bamboo-feeding planthopper genus Youtuus Chen & Gong, gen. n. with two new species Y.erythrus Gong, Yang & Chen, sp. n. and Y.strigatus Gong, Yang & Chen, sp. n. (Hemiptera: Fulgoromorpha: Caliscelidae: Ommatidiotinae: Augilini), are described and illustrated from China. Keys to the genera of Augilini and the species of Youtuus Chen & Gong, gen. n. are given.


Introduction
The planthopper tribe Augilini was erected by Baker (1915) in the subfamily Augilinae of family Issidae. The tribe was subsequently transferred to the family Lophopidae (Muir 1930). Later, Fennah (1987) accommodated the group as a subtribe of the tribe Ommatidiotini (Issidae: Caliscelinae). Emeljanov (1999) suggested treating Augilini as a tribe of subfamily Ommatidiotinae of family Caliscelidae based on external morphological characters including ovipositor structure which was confirmed by Gnezdilov (2003).
Modern fauna of the tribe Augilini comprises 13 genera with 27 species, known from the Oriental and Afrotropical regions (Gnezdilov and Bourgoin 2009;Gnezdilov 2013;Chen et al. 2014;Bourgoin et al. 2015). Twelve species within four genera have been reported from mainland China (Che et al. 2009;Chen et al. 2014;Yang and Chen 2014). The members of the tribe Augilini are characterized by forewing with clavus relatively long, hindwing well developed; abdomen elongate, narrowly cylindrical, with anterior and posterior margins of terga and sterna respectively transverse and chevron-like.
In this paper, a new genus with two new species of the tribe Augilini is established. Type specimens of these two species were collected from bamboo in southwestern China (Guizhou Province). The descriptions and illustrations are given. Keys to genera of Augilini and to species of the new genus are provided.

Materials and methods
Terminology follows Fennah (1987) and Chan and Yang (1994). Dry specimens were used for the descriptions and illustrations. External morphology was observed under a stereoscopic microscope and characters were measured with an ocular micrometer. Measurements were given in millimeters; body length was measured from the apex of the head to the apex of the forewing in repose. The genital segments of the examined specimens were macerated in 10% NaOH, washed in water, and transferred to glycerin. Illustrations of the specimens were made with a Leica MZ 12.5 stereomicroscope. Photographs were taken with KEYENCE VHX-1000 system. Illustrations were scanned with CanoScan LiDE 200 and imported into Adobe Photoshop CS7 for labelling and plate composition.
Remarks. The new genus seems very closely related to Pseudosymplanella, but can be distinguished from the latter by: 1) frons not visible in dorsal view (frons visible in dorsal view in Pseudosymplanella); 2) male anal segment with lateral margin with a verruciform process, ventral margin with apical third bearing a row of micro brush-like bristles and 8-14 large bristles apically (without verruciform process and any bristles in Pseudosymplanella); 3) posterior margin of male pygofer in lateral view without a spinelike process (with a spine-like process in Pseudosymplanella). According to the structute and venation of hind wing the new genus close to Madagascan Cano Gnezdilov, 2011. Etymology. The name is derived from transliteration of the Chinese "you-tu", meaning the anal segment with verruciform processes. It is masculine in gender.

Key to species of genus
Head and thorax. Width of vertex ( Figure 9) including eyes as wide as pronotum. Vertex (Figure 9) shorter in middle line than broad at base (0.8:1). Frons (Figure 10) 1.1 times longer in middle line than widest part. Pronotum (Figure 9) shorter in middle line than vertex (1:1.2). Mesonotum (Figure 9) 0.8 times as long as vertex and pronotum together in middle line. Forewing (Figure 12) with length 3.4 times than broad at widest part, ScP with three branches, RP single, M and CuA respectively forked in  (9-11, 14, 16, 18-20). two branches apically, Pcu uniting A 1 at basal 2/5 of clavus. Hindwing (Figure 13) 1.5 times as long as broad at widest part, ScP, RP and M single, CuA with two branches.
Male genitalia. Anal segment in dorsal view ( Figure 14) with length 2.7 times as long as widest part; in lateral view ( Figure 15) slender with dorsal margin sinuate, apically broadening to apical third, thence abruptly narrowed, lateral margin with verruciform process at basal third. Pygofer in lateral view (Figure 15) with dorsal margin distinctly shorter than ventral margin, upper half narrow, lower half wide, in posterior view ( Figure 16) nearly oval, with length 2.0 times as long as widest part; in ventral view ( Figure 18) with posterior margin roundly convex, anterior margin slightly concave. Genital style in lateral view ( Figure 15) nearly hook-like, outer surface with a small tooth process, apex sharp, directed basad; in ventral view ( Figure 18) nearly rectangle, with apex widest; in posterior view ( Figure 17) with dorsal 1/3 avicular, ventral 2/3 clavate. Penis in lateral view ( Figure 19) with a round ring structure near base of phallobase, a tooth-like process located at the ring inner-ventral margin, aedeagus with apex hook-shaped. Connective (Figure 19) straight and stub, fused with base of aedeagus, near its apical side with a short tooth process at base.

Distribution. Southwestern China (Guizhou).
Etymology. The specific name is derived from the Latin words "erythros", referring to the color of the frons.
Remarks. This new species is closely related to Y. strigatus Gong, Yang & Chen, sp. n., but differs in: 1) body mainly orange-red to red (brown to dark brown in strigatus); 2) male pygofer in posterior view without pair of processes (with pair of processes in strigatus); 3) lateral margin of anal segment bearing verruciform process at basal third (at basal half in strigatus).   broadly concave, dorsal margin with apical third dorsally uplifted and branched into two stubbed processes apically, the basal one with apical margin angularly convex, the apical one with apical margin roundly convex; in ventral view ( Figure 30) nearly rectangle, with basal third widest; in posterior view ( Figure 29) with base disciform, apex swollen, tongue-shaped. Penis in lateral view ( Figure 31) near base of phallobase with an irregular ring structure, of which base angularly convex, aedeagus with apex S-shaped. Connective in lateral view ( Figure 31) straight and slender, fused with base of aedeagus.

Distribution. Southwestern China (Guizhou).
Etymology. The specific name is derived from the Latin words "striga", referring to its color of the forewing.