﻿A new species of the genus Dentatissus Chen, Zhang & Chang (Hemiptera, Fulgoroidea, Issidae) from the Korean Peninsula, with a key to the genus

﻿Abstract A new species of the family Issidae (Hemiptera, Auchenorrhyncha, Fulgoroidea), Dentatissuslongispinosussp. nov., is described from the Korean Peninsula. Morphological information is presented with photographs based on male and female specimens. A key to species of the genus Dentatissus is also provided.


Introduction
The planthopper family Issidae Spinola (Hemiptera, Auchenorrhyncha, Fulgoromorpha) is the fifth-largest group in the superfamily Fulgoroidea, comprising 223 genera and 1,097 species distributed worldwide (Bourgoin 2023). Issidae is a morphologically unique taxon in the superfamily Fulgoroidea, with a generally oval or obovate body shape and with some taxa having a coriaceous forewing (Wang et al. 2016;Gnezdilov et al. 2022 Wang, Bourgoin & Zhang), which are mainly distributed in East Asia (Wang et al. 2016;Gnezdilov et al. 2022;Bourgoin 2023).
The genus Dentatissus Chen, Zhang & Chang belonged to the tribe Issini Spinola, but was transferred to the tribe Kodaianellini Wang, Zhang & Bourgoin (Wang et al. 2016). This group comprises three species [D. brachys Chen, Zhang & Chang, D. damnosus (Chou & Lu) and D. quadruplus Meng, Qin & Wang] and is distinguished by an anal tube with its maximum width near the middle in dorsal view and a phallic complex with two hooked processes (Chen et al. 2014;Chang et al. 2020;Zhang et al. 2020). Dentatissus damnosus is also known as an apple pest in China (Chou et al. 1985;Chen et al. 2014;Wang et al. 2016) (see detailed biology in Chen et al. 2014). In Korea, only D. brachys has been recorded up to date (Gnezdilov 2022).
In this study, D. longispinosus sp. nov. is described and recorded from the Korean Peninsula. Diagnosis and description of the new taxon along with photographs of the habitus and genitalia, in addition to a key to the species of Dentatissus, are provided.

Specimen collection
Specimens were collected in late August 2021 by sweeping the higher branches and leaves of Acer palmatum near paddy fields. Each individual was immediately aspirated and preserved in 99% ethanol (EtOH).

Observation, dissection, and type depository
Photographs of the habitus and measurements were taken using a LEICA DMC2900 adapted with a LEICA M165C microscope and Leica Application Suite Interactive Measurements ver. 4.13. All measurements are given in millimeters (mm). The forewing and hindwing were cut off from the thorax and placed in glycerin for observing veins. Female and male genitalia were carefully extracted using fine needles and subsequently soaked in 10% KOH solution at 70 °C for 10 minutes until cleared, and then placed on glass slides with glycerin for dissection. Illustrations of the male genitalia were created using parchment paper by tracing photographs and rendering the details in freehand while referring to actual specimens. The type specimens are deposited in CNU (Laboratory of Systematic Entomology, Chungnam National University, Daejeon, Korea). Distribution and host plant with an asterisk (*) indicate a new record. The distribution map was created using SimpleMappr (Shorthouse 2010).
Male genitalia. Pygofer in lateral view slightly wide basally, margins irregularly (Fig. 2C); Phallic complex long and symmetrical, complex endosome arising widely at apex (Figs 2E, G, 4A, C). Two pairs of ventral aedeagal hooks developed at ventral; the upper pair strongly curved to upward and surpassing aedeagus; the lower curved and not surpassing aedeagus (Figs 2F, 4B); genital style roundly widest at basal, pointed at apical; anterior margins simply protruded at middle, blunt; capitulum of style spinous, curved to ventrally (Fig. 2D); Anal tube in dorsal view, ovate and convex apically; anus placed at middle, anal column small, not reaching the posterior margin (Fig. 2B).
Measurements ( Etymology. This species is named after the elongated processes on the phallic complex. Distribution. Korea (South Chungcheong Province) (Fig. 5).

Discussion
This new species resembles D. brachys Chen, Zhang &Chang, 2014 andD. damnosus (Chou &Lu, 1985) in general features, but differs in having the anal tube ovate, anus much smaller than other species (Fig. 2B), ventral aedeagal hooks of phallic complex elongated, surpassing dorsal margins (Figs 2E-G, 4A-C), and anal tube and convex apically (Fig. 2B). Chen et al. (2014) provided diagnostic characters for species identification within this genus, with features on the prominent aedeagal hooks. However, the positions of the aedeagal hooks can vary depending on the methods used for specimen dissection. Therefore, additional features such as the shape of the anal tube should be considered for accurate identification. Furthermore, as this genus has been distinguished by male genitalia in previous research, it should be a requirement to examine the female genital characters in future studies. The genus Dentatissus is an endemic taxon found in East Asia, specifically in the Korean Peninsula and China (Chou et al. 1985;Chen et al. 2014;Wang et al. 2016;Gnezdilov 2022;Bourgoin 2023). They are known for containing a pest species in China (e.g., D. damnosus: fruit trees and Ligustrum quihoui, Chou et al. 1985;Chen et al. 2014;Wang et al. 2016) And, recently D. brachys has been recorded in Korea (Gnezdilov 2022). This group is closely associated with shrubs, trees, including fruit trees. Therefore, further research is needed on potential pests, including host information and habitat characteristics of D. longispinosus sp. nov. and for the genus and related groups.