Taxonomic study of the genus Unkanodes (Hemiptera, Fulgoroidea, Delphacidae) from Pakistan, with description of a new species

Abstract Unkanodes (Kwonianella) malamjabbensissp. nov. (Hemiptera, Delphacidae) is described and illustrated and U. latespinosa (Dlabola, 1957) is newly recorded from Malamjabbah, Swat, Pakistan. These two species represent the first records of the genus Unkanodes Fennah, 1956 from Pakistan. A key to the world’s species of the genus Unkanodes is provided.


introduction
The planthopper family Delphacidae currently consists of 2217 species in 427 genera (Bourgoin 2020). Delphacids are small insects that can be easily distinguished by the presence of a large, movable spur (the "calcar") at the apex of the hind tibiae (Bartlett 2014). Most delphacids are grass-feeders, although some feed on other monocots such as sedges and rushes, and some feed on dicots (Bartlett 2019). A number of species feed on economically important crops, such as sugarcane, maize and rice (Wilson and O'Brien 1987;Wilson et al. 1994). The plant order Poales accounts for more than 70% of their hosts, while all other plant orders provide only 3%. In the Poales group, the family Poaceae has the highest (52%) percentage of hosts, followed by Cyperaceae (16.5%), while the remaining families account for only 3% of host records (Bourgoin 2020).
The delphacid fauna of Pakistan has been poorly studied, with only ten species previously recorded from this country (Bourgoin 2020). This figure, consisting of about 0.4% of the world's described species, likely largely underrepresents the actual diversity of delphicids in this country. The genus Unkanodes was established by Fennah (1956) with the type species Unkanodes sapporona (Matsumura, 1935) from Che-Kiang (Zhejiang Province of China). Currently, this genus comprises nine species (Bartlett 2019) occurring in Afghanistan, Alaska, Austria, China, Denmark, Estonia, Finland, Germany, Greece, Iran, Japan, Lithuania, Mongolia, Poland, Russia, South Korea, Sweden, Taiwan, Turkey, Ukraine, Yugoslavia, and the U.S.A. (Bourgoin 2020). The genus Unkanodes is economically important and its members are vectors of many diseases in rice and cereals and also the causative agents of hopper burn diseases. Unkanodes albifascia is responsible for transmission of NCMV (Northern cereal mosaic virus), RBSDV (Rice black-streaked dwarf virus) and stripe disease. Unkanodes sapporona is involved in the transmission of NCMV, RSV (Rice stripe tenuivirus), and RBSDV. Unkanodes tanasijevici is reported to be a vector of IMMV (Iranian Maize Mosaic Nucleorhabdovirus), MIMV (Maize Iranian Mosaic Virus), MRDV (Maize Rough Dwarf Fiji Virus), and RBSDV (Bartlett 2019).
In this study, U. (Unkanodes) latespinosa (Dlabola, 1957) is recorded for the first time from Pakistan and a new species U. (Kwonianella) malamjabbensis sp. nov., is described.

Materials and methods
Specimens were collected from Pakistan and deposited at the Entomological Museum of Northwest A&F University (NWAFU) Yangling, Shaanxi, China. Morphological terminology follows Asche (1985), Wilson (2005) and Bartlett et al. (2014). The method for genitalia preparation and clearing follows Wilson and McPherson (1980) and Wilson (2005). Morphological characters were observed using the stereomicroscope Olympus SZX10. Measurements of characters are given in millimeters (mm). Photographs of the adults were taken using a Zeiss AxioCam ICc 5. Adobe Photoshop was used for labeling and plate composition of the obtained images.  (Matsumura, 1935), comb. by Fennah 1956 Type species. Unkana sapporona Matsumura, 1935: 131, by original designation. Diagnosis. Relatively slender, head slightly narrower than pronotum. Vertex longer than broad, its width at base not exceeding width of an eye, shallowly rounded at apical margin; carinae of vertex and frons distinct. Frons parallel-sided, about 2.0-2.5 times as long as wide, lateral margins parallel, narrowing upwards in apical 1/3; median carina of frons bifurcates near fastigium. Lateral carinae of pronotum diverging, vanishing before reaching posterior margin. Calcar with 10-20 well-developed teeth; apical tooth separate from the remaining teeth. Posterior margin of pygofer with a cut on the sides. Segment X (anal tube) with a pair of teeth or teeth absent. Styli flattened, diverging or more or less parallel beyond middle, with complex apices, zigzag-shaped bent and wide or narrowed and slanting outwards. Armature of diaphragm (bridge of pygofer) bearing a pair of teeth directed upwards or a projection with 2 apices. Aedeagus more or less straight, or bent ventrad, elbow-shaped, slightly asymmetrical due to location of gonopore and arrangement of teeth on aedeagal shaft (after Fennah 1956 andAnufriev andEmeljanov 1988).
This key is modified from Anufriev and Emeljanov (1988). Bartlett and contributors (2017) treated Ribautodelphax notabilis Logvinenko, 1970 as a synonym of Unkanodes tanasijevici (Dlabola, 1965) based on Nast (1987). In the present key, characters mentioned for U. tanasijevici are from the description of Ding (2006). Unkanodes (Unkanodes) paramarginata is not included in the key due to limited literature. Aedeagus narrowing abruptly in apical 1/3, with a lobe-like process on ventral aspect in lateral view (Fig. 21)  Remarks. Dlabola (1957) described this species based on specimens from Afghanistan and provides a detailed description. It can be distinguished from other species of Unkanodes by the large, widely-spaced processes of segment X (anal tube) and elbow-shaped aedeagus.  Swat-Khyber Pakhtunkhwa, Pakistan, 35°13'21.76"N, 72°25'32.93"E, 2993.39 m, 5 vii 2018, sweeping grasses, coll. Kamran Sohail. The area has a very diverse habitat for fruits and vegetables, and this species was collected in grasses near vegetable fields. This species is newly recorded for the fauna of Pakistan.
Colour. General body colour dark brown to black. Vertex pale, compartments with three distinct yellow spots. Carina on frons pale, intercarinal region dark brown, gena concolourous with intercarinal region, compound eyes greyish. Antenna yellowish slightly darker at junction of scape and pedicel. Pronotum and mesonotum medially with a white stripe; darker at adjoining areas, extreme lateral margins and median carina white, lateral carina concolourous with adjoining regions. Forewings dark brown to black, apical and anal margins pale. Legs yellowish, spines with black apices. Abdominal tergites darker, segments IX and X lighter, pygofer brown.
Remarks. This new species was collected in a grass habitat near ponds. The Type locality is an understudied habitat for fulgoroids and the region reflects a true diversity of planthoppers for future prospects.
Female. Unknown. Etymology. The new species is named after the type locality 'Malamjabba'. Diagnosis. The new species is externally similar to U. (Kwonianella) albifascia which also has a white stripe on the thorax and median margins of the forewings. However, it can be separated by the distinctly separated process of the pygofer bridge, widely diverging in U. (Kwonianella) malamjabbensis sp. nov. but very short and bifurcate at the apex in U. (Kwonianella) albifascia (Anufriev and Emeljanov 1988, Figs 2, 6;p. 412); and apical half of aedeagus gradually curved ventrad bearing a lobe-like process on the ventral aspect in U. (Kwonianella) malamjabbensis sp. nov. versus the apical half of the aedeagus slanting dorsad without a lobe in U. (Kwonianella) albifascia (Anufriev and Emeljanov 1988, Fig. 4;pp. 409, 412). Unkanodes (Kwonianella) malamjabbensis sp. nov. is also close to U. (Kwonianella) insularis Anufriev and U. (Kwonianella) sympatricus Anufriev in external appearance but can be distinguished by the distinct shapes of the aedeagus and parameres. and Dr. Tehseen Javed (College of Water Resources and Architecture Engineering, NWAFU) for providing the distributional map. We also extend our thanks to anonymous reviewers and the editor for their valuable suggestions and comments. This study was supported by the National Natural Science Foundation of China (31420103911) and The Ministry of Science and Technology of the People's Republic of China (2005DKA21402).