A new species of the idiocerine leafhopper genus Chinaocerus Zhang & Li (Hemiptera: Cicadellidae) from northwest China, with a checklist and key to species Author Liu, Guihua College of Life Sciences & Technology, Inner Mongolia Normal University, Hohhot 010022, China Author Yang, Hefeng Cuiwei School, High School Affiliated to Renmin University of China, Beijing, 100036, China & Fujian Paleo-diary Bioresearch Centre, Fuzhou 350001, China Author Li, Guoqing Fujian Paleo-diary Bioresearch Centre, Fuzhou 350001, China Author Chen, Zhenning Key Laboratory of Medicinal Animal and Plant Resources of Qinghai-Tibetan Plateau in Qinghai Province, School of Life Science, Qinghai Normal University, Xining, 810008, China. Author Zhang, Bin College of Life Sciences & Technology, Inner Mongolia Normal University, Hohhot 010022, China & Key Laboratory of Biodiversity conservation and Sustainable utilization for College and University of Inner Mongolia Autonomous Region, Hohhot 010022, China. text Zootaxa 2022 2022-03-04 5105 3 445 450 journal article 20333 10.11646/zootaxa.5105.3.7 32379469-46c5-4bee-bf00-f2076938f668 1175-5326 6332872 7B253F9B-37AB-43E1-8EA5-67D4631B55BB Chinaocerus dentatus Zhang sp. nov. ( Figs 1–4 , 5–6 , 7 , 8–17 ) Male. Yellowish brown. Vertex ( Fig. 1 ) with two small black spots closer to adjacent eyes than to median line. Face pale yellow ( Fig. 5 ) with dark brown maculae near dorsal margin, eyes lemon yellow. Pronotum ( Figs 1–2 ) yellowish brown with pair of triangular black marks on anterior margin, posterior margin grayish white. Scutellum light brown with basal triangles dark brown, a round dark spot on either side of median line. Forewings ( Fig. 2 ) yellowish brown, veins dark brown. Male dorsal basal abdominal apodemes ( Fig. 8 ) shorter than ventral ones, attaining posterior margin of sternite III. FIGURES 1–4. Dorsal and lateral habitus of Chinaocerus dentatus Zhang sp. nov .. 1–2. Male; 3–4. Female. FIGURES 5–6. Head and face of Chinaocerus dentatus Zhang sp. nov. , 5. Male; 6. Female. Male genitalia. Pygofer lobe ( Figs 9–10 ) elongate and narrow, with dorsal anterior apodeme developed; anal collar ( Fig. 9 ) with arms elongate with apices hook-like. Apophysis of style ( Fig. 11 ) bearing approximately 15 fine lateral setae distally. Aedeagus ( Figs 14–15 ) with well developed dorsal apodeme bearing pair of acute, fin-like lateral extensions; shaft tapered from base to apex in both lateral and posterior view, in posterior view with pair of very short, indistinct lateral prepical projections above gonopore, in lateral view sinuate, apex foot-like with prepical heel at level of gonopore and relatively broad distal toe. FIGURE 7. Photo of live individuals. C. dentatus female and male. Female. Color ( Figs 3–4 ) similar to male but face brighter yellow, triangular black marks on pronotum smaller and scutellum markings paler. Female genitalia. Second valvulae ( Figs 16–17 ) regularly broadened in lateral view, bearing approximately 10 teeth along dorsal margin. Measurements (mm). Male: body length 5.35–5.5, face length 1.45–1.52, width 1.8–1.85; distance between ocelli 0.45–0.56; distance from ocellus to eyes 0.34–0.35; medial length of pronotum 0.57–0.64, width 1.56–1.57; scutellum length 0.86–86, width 1.15–1.27. Female: body length 6.0–6.15, face length 1.65–1.71, width 1.95–1.98; distance between ocelli 0.56–0.58; distance from ocellus to eyes 0.34–0.36; medial length of pronotum 0.64–0.68, width 1.64–1.66; scutellum length 0.96–0.98, width 1.25–1.27. Material examined. Holotype : ♂ , China , Qinghai Province , Huzhu County , 17. viii. 2007 , Bin Zhang. Paratypes: 3♀♀ , same date as holotype; 1♂ , China , Gansu Province , Zhangxian County , 04. x. 1987 , Zhitai Sun ; 1♀ , China , Gansu Province , Mount Lianhuashan , 04. x. 1987 , Zhitai Sun ; 15♂♂ , 21♀♀ , China , Qinghai Province , Menyuan County ( 43.31496°N , 102.81495°E ), altitude 2686 m , 26. vii. 2021 , Bin Zhang ; 3♂♂ , 4♀♀ , China , Qinghai Province Menyuan County , 26. iv. 2021 , Hefeng Yang and Guoqing Li. Host plant. Salix sp. Distribution. China : Qinghai and Gansu . Diagnosis. C. dentatus resembles C. kangdingensis but differs in having the anal collar with arms elongate and apices hook-like, and the aedeagus with a lamellate process with serrated margins on the preatrium and the shaft lacking lamellate processes at midlength. Etymology. The species name refers to the dentations on the lamellate processes of the dorsal apodeme of the aedeagus.