Taxonomic review of Rhyacobates Esaki, 1923, with descriptions of three new species (Hemiptera: Heteroptera: Gerridae) Author Leng, Zhaoqi 89B546A1-5B53-4C03-9098-FBB36BC9EC85 Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, 300071, China. zhaoqileng0712@gmail.com Author Tran, Anh Duc 3CB36F17-D917-4600-B888-C33B1C04259F Faculty of Biology, VNU University of Science, Vietnam National University, Hanoi, Nguyen Trai, Thanh Xuan, Hanoi, Vietnam. tran.anhduc@hus.edu.vn Author Ye, Zhen B095C7FB-E95B-4D0D-A61F-09B0B223571F Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, 300071, China. yezhen1987331@nankai.edu.cn text European Journal of Taxonomy 2023 2023-09-28 893 1 1 73 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2285/9863 journal article 274285 10.5852/ejt.2023.893.2285 e441bc9d-bb44-4ee6-b29f-a6724b96592b 2118-9773 8385630 D9DA4879-BC1D-4947-96E8-7D574DE334BA Rhyacobates svenhedini ( Lundblad, 1934 ) Figs 2E , 3P , 4M–N , 5O , 7F , 8L , 34 Esakobates svenhedini Lundblad, 1934: 23–25 , pl. 2 fig. 10 (original description). Rhyacobates svenhedini – Hungerford & Matsuda 1959: 69–72 . — Matsuda 1960: 273–276 . — Andersen & Chen 1995: 61 , figs 24–25 (with remarks). Diagnosis Body length of apterous females 10.30–11.59, of apterous males 7.21–7.90. Female: pronotum mainly black with a median brownish-yellow spot, mesonotum with a median brownish-yellow stripe, metanotum medially with a subtriangular yellow marking and with a sharp apex angle ( Figs 2E , 3P , 34A ); posterior margin of abdominal mediotergite VII with a short median process; posterior margin of abdominal segment VII with four distinct processes dorsally, including two lobe-like processes on each connexival corner ( Fig. 34D–F ): one long, posteriorly directed outer process and a smaller, shorter, pointed inner process (in some individuals, the inner process is very small or indistinct); posterior margin of sternum VII with a small angular median process ( Fig. 34E ). Male: middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 34J ); length of middle tibia ca 1.3 times length of hind tibia; proctiger relatively large, with angular lobes laterally ( Figs 7F , 34K ); paramere strongly curved at basal third, distal part slender, with hook-shaped apex ( Figs 8L , 34L ). Material examined Non-type specimens CHINA – Sichuan Province • 31 ♁♁, 52 ♀♀ (apterous); Guang-yuan City , Qing-chuan County , Tang-jia-he; 32°31′25.1″ N , 104°49′23.7″ E ; 1077 m a.s.l. ; 16 Jul. 2016 ; Chen-guang Zheng leg.; NKUM • 2 ♁♁ (macropterous); Guang-yuan City , Qing-chuan County , Tang-jia-he; 32°31′25.1″ N , 104°49′23.7″ E ; 1077 m a.s.l. ; 16 Jul. 2016 ; Chen-guang Zheng leg.; NKUM . Supplemental description Apterous female MEASUREMENTS . Body length 10.30–11.59, width 2.70–3.22, head width 1.56, interocular width 0.76, eye length (dorsal view) 0.61; relative lengths of antennal segments I–IV: 5.02: 1.22:1.34:1.23; pronotum: length 0.91,width 1.94;mesonotum: length2.59, width 3.16; metanotum:length 0.82, width 2.68;abdomen length (ventral view) 6.80; abdominal sternum VII: length 2.03, width 1.41; abdominal mediotergite I: length 0.54, width 1.36; relative lengths of leg segments (femur:tibia: tarsal segment I:tarsal segment II): fore leg: 5.19: 4.63:2.48:1.04, middle leg: 13.91:7.10: 3.32: 0.51, hind leg: 13.61:5.56:0.15:0.24. COLORATION . Median black spot of head posteriorly bifurcate. Pronotum mainly black with a median brownish-yellow spot. Mesonotum mainly black with a median brownish-yellow stripe, metanotum medially with a subtriangular yellow marking and with a sharp apex angle ( Figs 2E , 3P , 34A ). Connexivum dorsally brownish-yellow. Abdominal tergum I with a median yellow marking. Mesosternum chiefly blackish with a median subtriangular yellowish spot ( Fig. 34B ). Abdominal venter light yellow. ABDOMEN . Abdomen relatively long, caudal part moderately curved dorsad ( Fig. 34C ). Connexival margin of abdominal segments I–II erect, of III–VII reflexed ( Fig. 34A ), meeting each other above terminal mediotergites ( Fig. 34A, D ). Posterior margin of abdominal mediotergite VII with a short median process. Abdominal segment VII elongate, about as long as two preceding abdominal segments together ( Figs 5O , 34C ). Posterior margin of abdominal segment VII with four distinct processes, including two lobe-like processes on each connexival corner ( Fig. 34D–F ): one long, posteriorly-directed outer process and a smaller pointed inner process (in some individuals, the inner process very small or indistinct), posterior margin of sternum VII with a small median process ( Fig. 34E ). Apterous male MEASUREMENTS . Body length 7.21–7.90, width 1.70–2.22, head width 1.36, interocular width 0.72, eye length (dorsal view) 0.51; relative lengths of antennal segments I–IV: 3.42: 1.08:1.23:0.93; pronotum: length 0.69, width 1.45;mesonotum: length2.22, width 2.22; metanotum:length 0.66, width 2.09;abdomen length (ventral view) 3.53; abdominal sternum VII: length 0.54, width 1.04; abdominal mediotergite I: length 0.27, width 0.98; relative lengths of leg segments (femur:tibia: tarsal segment I:tarsal segment II): fore leg: 4.44: 3.84:1.29:0.78, middle leg: 12.90:6.85: 2.83: 0.51, hind leg: 13.3: 4.23: 0.21: 0.15. Fig. 34. Morphological features of Rhyacobates svenhedini ( Lundblad, 1934 ) . A . Body of female, dorsal view. B . Body of female, excluding head and prothorax, ventral view. C . Body of female, lateral view. D . Abdominal end of female, dorsal view. E . Abdominal end of female, ventral view. F . Abdominal end of female, lateral view. G–H . Body of male, apterous form (G) and macropterous form (H), dorsal view. I . Body of male, excluding head and prothorax, ventral view. J . Basal part of right middle leg of male, ventral view. K . Proctiger of male, dorsal view. L . Left paramere, lateral aspect, two different views. Scale bars: A–J = 1 mm; K–L = 0.2 mm. C OLORATION. Median black spot of head posteriorly bifurcate. Pronotum mainly black with a median brownish-yellow spot. Mesonotum mainly black with a median brownish-yellow stripe. Metanotum chiefly blackish, without yellow markings ( Figs 4M , 34G ). Connexivum dorsally blackish. Mesosternum chiefly blackish with a median subtriangular yellowish spot, narrower than that of female ( Fig. 34I ). Abdominal venter light yellow. LEG . Middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 34J ). GENITALIA . Abdominal segment VIII ventro-laterally impressed. Pygophore large, ovate. Proctiger relatively large, with angular lobes laterally ( Figs 7F , 34K ). Paramere strongly curved at basal third, distal part slender, with hook-shaped apex ( Figs 8L , 34L ). Macropterous male Similar to apterous female in general structure and coloration with following exceptions: thorax with a pronotal lobe, anterior part with a subrhombic yellow marking, posterior part elongate, covering most of mesonotum; posterior margin broadly rounded and brownish ( Figs 4N , 34H ). MEASUREMENTS . Body length 7.35, width 2.11, head width 1.30, interocular width 0.62, eye length (dorsal view) 0.51;relative lengths of antennal segments I–IV: 3.88:1.05: 1.18: 0.99; pronotum: length2.71,width 2.14; mesonotum width 2.11; metanotum width 1.80; relative lengths of leg segments (femur:tibia: tarsal segment I: tarsal segment II): fore leg: 3.96: 3.04:1.23:0.61, middle leg: 11.36:6.31: 3.05: 0.75, hind leg: 11.67: 4.99: 0.25: 0.21. Distribution China : Fujian , Sichuan ( Andersen & Chen 1995 ). Comparative notes Rhyacobates svenhedini is most similar to R. lundbladi ; see comparative notes under R. lundbladi .