﻿Two new species of the planthopper genus Usana Distant, 1906 (Hemiptera, Fulgoromorpha, Achilidae) from China

﻿Abstract Two new species of the achilid planthopper genus Usana Distant, 1906 (Hemiptera, Fulgoromorpha, Achilidae, Myconinae, Plectoderini), U.tongmaiensis Long & Huang, sp. nov. and U.rotalarius Long & Huang, sp. nov., are described and illustrated from Xizang and Chongqing. A key to all known species and a map of geographic distributions for Chinese taxa is provided.


Introduction
Achilidae Stål, 1866 constitutes one of the moderate-sized families within planthoppers (Hemiptera, Fulgoromorpha) with 521 described species in 162 genera and three subfamilies: Apatesoninae Metcalf, 1938, Achilinae Stål, 1866, and Myconinae Fennah, 1950(Bartlett et al. 2018;Bourgoin 2023); only the last two only subfamilies occur in China.Plectoderini is the richest tribe in Achilidae, with 353 species and 99 genera worldwide, of which 17 genera and 80 species occur in China.Usana Distant, 1906 is a small genus of planthoppers in the tribe Plectoderini with 10 species.It has recently been reviewed (Long et al. 2015).It comprises only 2.8% of known Plectoderini diversity (Bourgoin 2023).
Recent study of some Chinese Usana specimens has revealed two new species, described here as U. tongmaiensis Long & Huang, sp. nov

Materials
Type materials are deposited in the Institute of Entomology, Guizhou University, Guiyang, Guizhou Province China (IEGU).

Preparations and illustration
The colour photographs were taken using a Canon 5D Mark IV camera in conjunction with a Canon EF 100 mm F/5.6L IS USM macro lens, and a Godox MF12 macro flash 2-light kit was used as light source.Zerene Stacker v. 1.04 was used for focus stacking.External morphology was observed under an Olympus SZX7 stereoscopic microscope.Measurements were made with the aid of a Keyence VHX-1000E system.The genital segments of the examined specimens were macerated in 10% KOH, then transferred to glycerol for examination.Drawings and external morphology were done with the aid of a Leica MZ 12.5 stereo microscope.Illustrations were scanned by a Canon CanoScan LiDE100 and imported into Adobe Photoshop CS6 for labeling and plate composition.

Measurements and abbreviations
Body length length of specimen from apex of vertex to fore wing apex (in dorsal view); A/B width of vertex at posterior margin / length of vertex at midline; C/D length of frons at midline / maximum width of frons; D/E maximum width of frons / width of frons at apex; F/C length of postclypeus at midline / length of frons at midline; G/H length of apical / length of subapical; I/B length of pronotum at midline / length of vertex at midline; J/I length of mesonotum at midline / length of pronotum at midline; J/B+I length of mesonotum at midline / cumulative length of vertex and pronotum at midline; K/L length of fore wing from the base to the apical margin in median portion / width of fore wing at the widest part; M/N length of hind wing from the base to the apical margin in median portion / width of hind wing at the widest part.
Diagnosis.Head.Width of head at eyes 0.8-0.9times wider than pronotum.Vertex not declivous, broader at base than long in middle line, median carina distinct, anterior margin carinate, triangular areolets at lateroapical angles of head distinct, posterior margin broadly concave.Frons longer at mid-line than at widest part, basal margin truncate, median carina distinct, lateral margins carinate.Rostrum almost or just reaching post-trochanter, with subapical segment shorter than apex.
Male terminalia.Length of anal segment in dorsal view at least equal to its width; apical margin of anal segment distinctly excavated at midline; pygofer in lateral view with dorsal margin distinctly shorter than ventral margin, medioventral process entire or with apex divided into 2 branches.Genital style with 3 processes arising from its dorsal margin, inner surface near anterior margin with a long, outwardly directed process.Phallobase sheathed, generally asymmetrical, with apical 1/2 divided into a dorsal, 2 lateral, and a ventral lobe: dorsal lobe relatively short, lateral lobes valviform, and ventral lobe with apical margin incised at midline and with subapical surface in middle giving rise to a long process, directed basad.Each phallic appendage generally not exceeding apical margin of phallobase, with a protrusion between basal 1/4 to 1/3.
Colouration.Generally yellowish white to dark brown (Figs 1, 2).Vertex yellowish white with 2 longitudinal, dark-brown stripes along midline (Figs 1, 9).Face yellowish white; frons with 1 dark-brown, straight band at proximal base and end; end part of postclypeus dark brown (Fig. 10).Genae yellowish white, with a brown band in front of compound eyes; eyes reddish brown, ocellus yellowish white; Antenna yellowish brown, with 1 dark-brown, oblique stripe below it (Fig. 11).Rostrum yellowish brown, with end brown.Pronotum yellowish brown with 2 darkbrown, longitudinal stripes between lateral carinae, lateral lobe brown behind eyes, and ventral lobe with a longitudinal brown stripe (Figs 1, 2, 9).Mesonotum brown, with middle and lateral ridges yellowish brown (Figs 1, 9).Tegulae with inner half yellowish white, external half yellowish brown (Fig. 9).Tegmen yellowish white to dark brown (Figs 1, 2, 5).Costal area yellowish brown.Postcostal cell yellowish white to brown, with brown near base and on end areas, medial area with 3 irregular, dark-brown spots.Radial area yellowish brown to dark brown; C1a yellowish brown; C1' and C1b dark brown.Radial cell yellowish brown to dark brown; C2 and C2' dark brown.Medial area yellowish brown to dark brown; C3 with irregular, deep-brown markings; C3a and C3' dark brown.Median cell yellowish brown to dark brown; C4 with irregular, deep-brown markings; C4' dark brown.Areola postica yellowish brown to dark brown; C5' dark brown.Cubital cell brown to deep brown, with 2 yellowish-white markings at near the middle.Basal cell end half deep brown.Area between CuP and Pcu with base half yellowish white and half brown.Area between Pcu and wing margin brown, with base yellowish white.Hind wing pale brown; veins brown.Legs and abdomen yellowish brown (Fig. 2).Head and thorax.Vertex not concave, slightly declivous; triangular areolets at lateroapical angles of head distinct; anterior margins carinate; arcus convex forward; lateral margins carinate, relatively straight, and diverging basad; posterior margin broadly concave (Figs 1, 9).Frons slightly convex in lateral view; upper margin (apex) truncate; median carina evident; lateral margin carinate, sinuately diverging to level of antennae, thence gradually incurved to suture (Fig. 10).Clypeus with distinct median and lateral carinae (Fig. 10).Rostrum just reaching trochanter of hind legs (Fig. 2).Antenna nearly cylindrical, not sunken as a depression (Figs 2,10,11).Ocelli separated from eyes (Fig. 11).Pronotum with 3 distinct carinae; anterior margin of disk broadly convex; posterior margin obtusely angled, concave at middle; median carina distinct; lateral carinae straight, slightly diverging rearward, attaining hind margin; lateral lobe with a small longitudinal carina between eye and tegula (Figs 1, 9).Mesonotum wider, with 3 obvious, nearly parallel carinae (Figs 1, 9).
Male terminalia.Anal segment in dorsal view (Fig. 13) with maximum width near middle, hence narrowing basad and apically; apical margin roundly concave at middle, length of anal segment ~1.7 times as long as width; anal style not exceeding apical margin of anal segment.Anal segment in lateral view (Fig. 14) with nearly right-angle bend from base to end.Pygofer in lateral view (Fig. 14) with dorsal margin distinctly shorter than ventral margin, anterior margin deep concave at 1/3 its length; posterior margin near middle obviously serrated, convex.Medioventral process of pygofer in ventral view (Fig. 12) entire, apically narrowed, with apical margin angularly incised.Genital style slightly narrowing apically, with apex roundly convex; dorsal margin gives rise to 2 large, sharp processes and 1 short, blunt process; inner surface near anterior margin with a slender, outwardly directed, finger-like process (Figs 12,28,29).Aedeagus structure relatively simple, nearly symmetrical, nested (Figs 21,22).Lateral periandrial lobe of phallobase obviously longer than dorsal and ventral periandrial lobe (Figs 21,22).Dorsal periandrial lobe unpaired, in dorsal view finger-like (Fig. 21); left and right lateral periandrial lobes nearly symmetrical, with apical margins roundly convex.Ventral periandrial lobe in ventral view (Fig. 22) along inner margin of each lateral side from subapical to middle with a longitudinal group of teeth, subapical surface in middle gives rise to a long process, directed basad, with its apical margin roundly convex.Inner penis rods elongate, lanceolate, curved, apically pointed, basally broadly fused together (Fig. 23).
Etymology.The species name refers to the type locality, Tongmai, Xizang, China.Host plant.Unknown.Distribution.China (Xizang).Diagnosis.The salient features of this new species different from other species in Usana are as follows: 1) anal segment in lateral view (Fig. 20) with nearly right-angle bend from base to end; 2) medioventral process of pygofer in ventral view (Fig. 18) entire, apically convex, concave at base; 3) dorsal periandrial lobe in ventral view horseshoe-shaped (Fig. 27), inner margin middle with a longitudinal group of teeth, subapical surface in middle gives rise to a short process with its apical margin sharp convex, directed based; 4) inner penis rods elongate, blade-like, curved, apically pointed (Fig. 24).
Male terminalia.Anal segment in dorsal view (Fig. 19) with apical margin roundly concave in middle, length ~1.7 times as long as width; anal style not exceeding apex of anal segment.Anal segment in lateral view (Fig. 20) with nearly right-angle bending from base to end.Pygofer in lateral view (Fig. 20) with dorsal margin distinctly shorter than ventral margin; anterior margin concave and narrowest at 1/3 its length; posterior margin near middle obviously serrated, convex.Medioventral process of pygofer in ventral view (Fig. 18) entire, apically convex, concave at base.Genital style slightly narrowing apically, with apex roundly convex, dorsal margin gives rise to 1 sharp process and 1 blunt process; inner surface near anterior margin with a slender, outwardly directed, finger-like process (Figs 18,30,31).Aedeagus structure relatively complex, nested (Figs 26,27).Aedeagus with phallobase in midline deeply fissure from base to subapex, dorsal lobe in dorsal view (Fig. 26) with apical margin sharp convex; ventral periandrial lobe obviously longer than dorsal periandrial lobe.Dorsal periandrial lobe in ventral view horseshoe-shaped (Fig. 27), middle of inner margin with a longitudinal group of teeth, subapical surface in middle gives rise to a short process with its tip sharply convex, directed based; left and right lateral periandrial lobes nearly symmetrical, with tips roundly convex.Inner penis rods elongate, blade-like, curved, apically pointed (Fig. 24).
Etymology.The species name is derived from the Latin word "rotalarius", which refers to the medioventral process of pygofer in ventral view (Fig. 18) apically convex.

Discussion
The genus Usana appears mainly distributed in the Sino-Japanese realm but six species are distributed in the tropics: U. concava, U. lineolalis, U. oblongincisa, U. yanonis, U. abdominalis and U. demochares.Among these, U. yanonis is the most widely distributed, since it also occurs in the Palaearctic and Oriental realms.Ten species (Fig. 35) occur in China, which appears to be a centre of endemism for the genus.At present, the biology of Usana species is very poorly known.Only one hostplant, Alangium platanifolium (Sieb. et Zucc.).Harms is known for the genus, but for several species, including U. aspergilliformis, U. fissura, U. lineolalis, U. oblongincisa, and U. unispina, no other etho-ecological data are known.