A new genus of the tribe Sarimini (Fulgoromorpha, Issidae) from the Guangxi Province of China

Abstract A new genus with a new species Eusarimissus hezhouensisgen. nov. et sp. nov. from Guangxi Province of China are described in the tribe Sarimini of the family Issidae. Molecular sequences of 18S, 28S and COXI genes are provided for the new taxon. Phylogenetic analysis places this taxon sister to a previously sequenced but not yet described Sarimini genus ‘Eusarima sp. 4’. Taxonomic notes are provided for the genus Eusarima Yang, 1994. The species Eusarima (Nepalius) iranica Gnezdilov & Mozaffarian, 2011 is transferred to the genus Sarima Melichar 1903.


Introduction
Without obvious morphological apomorphy, the tribe Sarimini Wang, Zhang & Bourgoin, 2016 was only recently revealed after a molecular phylogenetic analysis of the planthopper family Issidae. It represents an important tribe which is sister to two other emblematic sister tribes in Hemisphaeriinae: the Parahiraciini Cheng &Yang, 1991 andthe Hemisphaeriini Melichar, 1906 within the Issidae (Wang et al. 2016, Zhao et al. 2019. Currently, Sarimini includes 26 genera (Bourgoin 2020), plus several other genera already identified but not yet described which were provisionally labelled 'Gen. nov.', 'Eusarima sp. 1', 'sp. 2', and 'sp. 4' in Wang et al. (2016)'s analysis. The other taxa labelled with 'Gen. nov. apud Eusarima' and 'Eusarima sp. 3' were already described respectively as Longieusarima Wang, Zhang & Bourgoin, 2017(Wang et al. 2017 and Duplexissus Wang, Zhang & Bourgoin, 2019. In this paper, we describe an additional new genus, representing a new species from Guangxi Province of China. We also provide taxonomic notes about the genus Eusarima Yang, 1994 from which one species, Eusarima (Nepalius) iranica Gnezdilov & Mozaffarian, 2011, is transferred to the genus Sarima Melichar, 1903. Finally, the number and the diversity of the taxa, which progressively joined Sarimini since its description, allow now a better understanding of its morphological characteristics.

Materials and methods
The type specimens are deposited in China West Normal University, Nanchong, Sichuan Province, China. The specimens were collected by net capture during daytime. The genitalia were separated from the insect body using micro-scissors under a stereomicroscope Leica M205C, then transferred and boiled in a 5ml beaker with 10% NaOH solution for a few minutes until muscles were completely dissolved leaving only tegumentary structures. After rinsing in distilled water several times to clean the residual NaOH solution, genitalia were subsequently transferred to glycerine for final dissection and observation, and then stored under the specimen in a genitalia vial for final conservation. Photographs for external morphology and genitalia characters were taken using a Leica DFC camera attached to a Leica M205FA stereomicroscope and further refined with LAS X software. Morphological terminologies for male genitalia follow Bourgoin (1987), for female genitalia Bourgoin (1993), and for wing venation Bourgoin et al. (2015).
Total genomic DNA was extracted from the fore and middle legs of the holotype specimen using a Sangon Ezup column animal genomic DNA purification kit. The DNA of the genes (18S rRNA, 28S rRNA, COXI, Cytb) was amplified using the same primers and amplification procedures as in Wang et al. (2016). DNA sequencing was conducted by the Sangon Company (Shanghai, China). Contigs assembly was made using the software Seqman from package DNAstar v5.01 (www.dnastar.com). All sequences were registered in GenBank with accession numbers mentioned below.
MEGA v7.0 (Kumar et al. 2016) was used for performing alignments for a subset of taxa already analysed in Wang et al. (2016) but restricted to Sarimini plus the new genus. Phylogenetic analysis was performed using the software IQTREE v1.4.1 (Nguyen et al. 2015) with 10,000 bootstraps (Minh et al. 2013) and substitution models automatically selected with partitions unlinked. According to the results of Wang et al. (2016), genus Darwallia Gnezdilov, 2010 was chosen as an out-group for the analysis. FIGTREE v1.1.2 (Rambaut 2016) was used to visualize the tree. Diagnosis. This new taxon appears similar to Eusarima but differs by: 1) Vertex much longer, around 1.3 times wider than long in midline ( Fig. 1), but around 1.6 times wider in Eusarima (Chan and Yang 1994, fig. 45A); 2) MP vein forking late in apical 1/3, obviously after CuA (Fig. 4), while MP and CuA fork near middle, almost at the same level in Eusarima (Chan and Yang 1994, fig From Longieusarima, Eusarimissus is easily separated by its shorter and wider vertex, the longer sublateral carinae of frons widely surpassing the level of the ventral margin of the antenna, and the general schema of the tegmina with a longer ScP+RA vein and a late-forking MP vein, well after the forking of CuA. Male genitalia also easily differentiated these two genera by the long subapical aedeagus processes in Longieusarima, shorter and in the apical 3/4 in Eusarimissus. Description. Head with compound eyes a little wider than pronotum and mesonotum ( Fig. 1). Vertex hexagonal, a little wider than long in midline, median carina weakly present or absent on the disc; margins elevated, anterior margin obviously angularly convex at middle, lateral margins nearly straight and parallel, posterior margin angularly concave (Fig. 1). Frons rounded, wider than long, margins elevated; apical margin nearly straight, lateral margins expanding outward below antennae with lateral angles rounded (Fig. 3); median carina apparently elevated from apex extending to frontoclypeal suture (Fig. 3); sublateral carinae obviously elevated from the apex near to the base, but not reaching to the frontoclypeal suture, with lateral ventral angles rounded (Fig. 3). Frons smooth, without any tubercles (Fig. 3). Frontoclypeal suture strongly angularly convex (Fig. 3). Antenna with scape extremely short, pedicel rounded (Fig. 3). Clypeus smooth, without median carina (Fig. 3). Rostrum reaching to midcoxae, apical segment almost the same length with subapical one. Gena in lateral view oblique (Fig. 2). Pronotum triangular, almost same length with vertex in midline; margins elevated, anterior margin angularly protruded, posterior margin straight; median carina very weakly present or absent, with several inconspicuous tubercles on the disc (Fig. 1). Mesonotum triangular, a little wider than pronotum in midline, tricarinated on the disc, anterior margin straight (Fig. 1). Forewings obviously longer than broad, longitudinal veins distinctly elevated (Figs 1, 2, 4); costal area narrow, ScP+R forked at the base, ScP+RA and RP veins parallel, both extremely long, respectively extending to the apical 4/5 of costal margin and the apical margin (Figs 2, 4); MP straight, bifurcated into MP 1+2 and MP 3+4 at apical 1/3, forking again or not apically (Figs 2, 4); CuA bifurcated well before MP, slightly before Pcu and A1's junction (Figs 1, 2, 4); clavus closed, CuP long, extending to the same level of ScP+RA, Pcu and A1 fused slightly beyond the middle of clavus (Fig. 4). Hind wings developed, of Sarimini type with 3-lobes (Fig. 5); Pcu-A1 lobe as wide as ScP-R-MP-Cu lobe, Pcu and A1 anastomosing at a medium distance, Pcu, A1 1 and A1 2 single (Fig. 5); A2 lobe developed, as wide as Pcu-A1 lobe, margin regularly slightly convex, A2 vein simple, non-branched (Fig. 5). Metatibia with two lateral spines on apical half (Fig. 2).
Etymology. This name is an arbitrary association between the genera names "Eusarima" and "Issus" referring to the close relationship of this genus to Eusarima in the Issidae tribe Sarimini. The gender is masculine.
Female genitalia. Anal tube in dorsal view conical, 1.6 times longer in midline than widest part (Fig. 12); apical margin sharp, lateral margins gradually broadening from apex to basal 1/3 (Fig. 12); anal opening situated at basal 1/3 (Fig. 12). Gonoplacs in dorsal view with outer lateral margins roundly convex, the apical part and Figure 19. Maximum likelihood tree of Sarimini species based on combined sequences (18S, 28S, COXI, Cytb) with Darwallia as outgroup. At each node, values denote ML bootstrap support. The name 'Gen. nov.', 'Eusarima sp. 1','sp. 2',and 'sp. 4' refer to the same taxa as in Wang et al. (2016). median part membranous (Fig. 13); in lateral view rectangular, 1. 6 times longer in longest part than widest part, the apical margin rounded (Fig. 14). Gonapophysis IX in lateral view broad, dorsal margin elevated and convex at middle, basal 1/3 with a needle-like process (Fig. 15). Gonapophysis IX in dorsal view widest near middle, basal half broader than apical half, outer area concave inward near apical 1/3 (Fig. 16). Anterior connective lamina of gonapophysis VIII with three teeth at apex and three teeth on the outer lateral margin, inner lateral margin without teeth (Fig. 18). Endogonocoxal process reaching to the same level of apex of anterior connective lamina (Fig. 18). Gonocoxa VIII long rectangular, perpendicular the gonapophysis VIII (Fig. 18). Apical margin of sternite VII mostly straight, with middle part very shallowly incised and two prominent dorso-lateral angles in ventral view (Fig. 17).

Discussion
Analysis of all Sarimini genera currently available for a molecular phylogeny, places Eusarimissus gen. nov. as sister to Eusarima sp. 4 which are both sister to the genus Longieusarima. Morphologically, Eusarimissus gen. nov. resembles the genus Eusarima from which it could be easily separated by the forewing venation and the presence of the posterolateral processes of the dorsal lobe of the periandrium in the latter genus.
Eusarima is a large genus including 37 species (Bourgoin 2020). It was divided into two subgenera: Eusarima and Nepalius Dlabola, 1997, the latter synonymized with the former by Gnezdilov (2009) before being revalidated as a subgenus by Gnezdilov and Mozaffarian (2011). Subgenus Nepalius currently contains three species distributed in the Western Palaearctic area (Nepal, Iran and Pakistan). It represents probably a separated valid independent genus with its type species Eusarima (Nepalius) helleriana (Dlabola, 1997) and Eusarima (Nepalius) albifrons Gnezdilov, 2016. However, according to its forewing conformation (particularly by its short recurved ScP+RA to RP), Eusarima (Nepalius) iranica Gnezdilov & Mozaffarian, 2011 is here transferred in the genus Sarima Melichar, 1903 as Sarima iranica (Gnezdilov & Mozaffarian, 2011) comb. nov. Because Sarima is probably also a composite genus in need of revision, we don't exclude the possibility that S. iranica could belong to an independent genus itself. Thirty-one other species in the nominal subgenus Eusarima occur in Taiwan, which is regarded as an example of extensive insular diversification (Gnezdilov 2016). Two more species were also described from Japan and another one from Guangxi Province, China. The latter, Eusarima (Eusarima) triphylla, differs from all other Eusarima and Sarimini species by several characters that need to be confirmed: a CuA 1 vein apically single, a 3-forked Pcu vein and an incomplete A1 vein. Because the published figure looks rather schematic (Che et al. 2012, fig. 7), this venation needs to be rechecked for confirmation and sequencing this species for comparison with other Sarimini taxa would be of great interest as obviously its generic placement remains dubious. Unfortunately, we don't also know the precise phylogenetic placement of the genus Eusarima itself within the Sarimini: all species analysed in Wang et al. (2016) and labelled 'Eusarima sp.', although quite close to Eusarima species, are not true Eusarima taxa.
The diversity of the taxa that progressively joined the Sarimini tribe, allows us now to better clarify the morphological characteristics of the group. Indeed, within the Issidae, Sarimini shares a specific 3-lobed hind wing conformation with an A2 lobe as wide or wider than the other lobes, often notched at the A2 extremity, and with several venation characteristics that seems emerging as a specific combination for the group: lobes with non-reticulated venation, Pcu-A1 lobe usually without transverse veins, cubital band area between CuP and Pcu always much wider than the intra-cubital band area between CuA and CuP, MP single, Pcu anastomosing at some distance with A1 anterior branch, Pcu, A1 1 , A1 2 and A2 single.