Rhyacobates edentatus Andersen & Chen 1995
Creators: name: Leng, Zhaoqi
name: Tran, Anh Duc
name: Ye, Zhen
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Gerridae
Rhyacobates
Rhyacobates edentatus

description: Rhyacobates edentatus Andersen & Chen, 1995
Figs 3J, 4G, 5I, 6I, 8G, 27–28
Rhyacobates edentatus Andersen & Chen, 1995: 63–64, figs 33–36 (original description).
Diagnosis
Body length of apterous females 7.21–9.64, of apterous males 5.70–6.62. Female: pronotum mainly black with a median brownish-yellow spot; mesonotum and metanotum mainly black with a median brownish-yellow stripe (Figs 3J, 28A); posterior part of abdomen curved dorsad to oblique position, both sides of abdominal segment VII dorsally folded mesad, almost meeting each other over mediotergite (Fig. 28D–F), posterior margin of sternum VII truncate or with obtuse angle (Fig. 28E). Male: middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row (Fig. 28I); length of middle tibia ca 1.9–2.0 times length of hind tibia; proctiger with angular lobes laterally (Figs 6I, 28J); paramere relatively slender, curved at basal third, distal part tapering towards hook-shaped apex (Figs 8G, 28K).
Material examined
Holotype (Fig. 27A–B)
CHINA • ♀ (apterous); Guangdong Province, Lian County, Yao-an Village; 30 Jul. 1962; Le-yi Zheng and Han-hua Cheng leg.; NKUM.
Paratypes (Fig. 27C–D)
CHINA • 3 ♁♁, 1 ♀ (apterous); same collection data as for holotype; NKUM.
Non-type specimens
CHINA – Chongqing City • 7 ♁♁, 8 ♀♀ (apterous); Nan-chuan Region, Jin-fo Mountain; 29°3′25.6″ N, 107°5′55.1″ E; 598 m a.s.l.; 19 Jul. 2022; Qiao Mu et al. leg.; NKUM. – Guangdong Province • 13 ♁♁, 10 ♀♀ (apterous); Qing-yuan City, Guang-dong-di-yi Mountain; 24°47′42.1″ N, 112°54′47.5″ E; 696 m a.s.l.; 21 Jul. 2019; Si-ying Fu leg.; NKUM • 1 ♁, 2 ♀♀ (apterous); Shao-guan City, Nan-ling; 24°54′58.4″ N, 113°2′47.6″ E; 513 m a.s.l.; 5 Jun. 2016; Ya-hui Zhen leg.; NKUM. – Guangxi Province • 1 ♁, 1 ♀ (apterous); Gui-lin City, Long-sheng County, Hua-ping National Nature Reserve; 25°41′11.5″ N, 109°56′59.1″ E; 540–800 m a.s.l.; 18 Jul. 2009; Zhong-hua Fan leg.; NKUM • 2 ♁♁, 3 ♀♀ (apterous); Laibin City, Jin-xiu County, Da-yao Mountain; 24°8′40.2″ N, 110°4′49.1″ E; 565 m a.s.l.; 25 Jul. 2019; Zhen Ye leg.; NKUM. – Guizhou Province • 1 ♀ (apterous); Zun-yi City, Kuan-kuo-shui National Nature Reserve; 28°5′9.4″ N, 107°14′47.5″ E; Jul. 2012; Tong-yin Xie leg.; NKUM. – Fujian Province • 1 ♁, 2 ♀♀ (apterous); Nan-ping City, Wu-yi Mountain; 27°38′53.1″ N, 117°58′20.1″ E; 18 Jul. 2018; Si-ying Fu, Kun Jiang and Xin Yang leg.; NKUM. – Hubei Province • 64 ♁♁, 55 ♀♀ (apterous); Huang-gang City, Ying-shan County, Jiu-gong Mountain; 29°22′08.6″ N, 114°34′36.5″ E; 700 m a.s.l.; 3 Aug. 2010; Wen-jun Bu et al. leg.; NKUM • 13 ♁♁, 16 ♀♀ (apterous); Huang-gang City, Ying-shan County, Jiu-gong Mountain; 29°23′59.7″ N, 114°39′24.5″ E; 130 m a.s.l.; 11 Jul. 2022; Zhao-qi Leng and Zhen Ye leg.; NKUM. – Hunan Province • 4 ♁♁, 5 ♀♀ (apterous); Shao-yang City, Dong-kou County, Luo-xi; 27°2′19.4″ N, 110°13′48.6″ E; 500 m a.s.l.; 27 Jul. 2016; Yan-chen Li and Chen-guang Zheng leg.; NKUM. – Jiangxi Province • 2 ♁♁, 2 ♀♀ (apterous); Lu-shan City, Gu-ling County; 9 Aug. 1934; O. Piel leg.; IZAS. – Sichuan Province • 4 ♁♁, 3 ♀♀ (apterous); Lu-zhou City, Huang-jing; 28°14′57.3″ N, 105°44′39.5″ E; 886 m a.s.l.; 7 Aug. 2016; Chen-guang Zheng leg.; NKUM • 1 ♀ (apterous); Le-shan City, Mu-chuan County, Hei-xiong Valley; 28°52′26.8″ N, 103°57′31.1″ E; 1090 m a.s.l.; 2 Aug. 2017; Chen-guang Zheng leg.; NKUM.
Supplemental description
Apterous female
MEASUREMENTS. Body length 7.21–9.64, width 3.03–3.53, head width 1.63, interocular width 0.66, eye length (dorsal view) 0.62; relative lengths of antennal segments I–IV: 4.18: 1.31: 1.35: 1.05; pronotum: length 0.81, width 1.71; mesonotum: length 2.57, width 3.30; metanotum: length 0.86, width 3.09; abdomen length (ventral view) 2.70; abdominal sternum VII: length 0.84, width 1.48; abdominal mediotergite I: length 0.49, width 1.29; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 4.17:3.66: 2.17: 0.95, middle leg: 12.27:7.72: 4.48: 0.48, hind leg: 12.78: 6.41: 0.21: 0.27.
COLORATION. Median black spot of head posteriorly bifurcate. Pronotum mainly black with a median brownish-yellow spot. Mesonotum and metanotum mainly black with a median brownish-yellow stripe (Figs 3J, 28A). Connexivum dorsally brownish-yellow. Abdominal tergum I yellow or with a yellow marking. Mesosternum chiefly blackish with a median subtriangular yellowish spot (Fig. 28B). Abdominal venter light yellow.
ABDOMEN. Abdomen relatively short, with posterior part curved dorsad to oblique position (Figs 5I, 28C). Connexiva erect anteriorly, reflexed above terminal mediotergites (Figs 3J, 28A), or never converging. Abdominal segment VII elongate (Fig. 28C), nearly as long as two preceding abdominal segments together ventrally, completely enclosing genital segments (Fig. 28D). Both sides of abdominal segment VII folded mesad on dorsal side, almost meeting each other over mediotergite (Fig. 28D–F), posterior margin of sternum VII truncate or with obtuse angle (Fig. 28E).
Apterous male
MEASUREMENTS. Body length 5.70–6.60, width 1.70–1.90, head width 1.26, interocular width 0.50, eye length (dorsal view) 0.49; relative lengths of antennal segments I–IV: 2.90: 0.95: 1.01: 0.75; pronotum: length 0.65, width 1.35; mesonotum: length 1.85, width 1.94; metanotum: length 0.55, width 1.78; abdomen length (ventral view) 2.21; abdominal sternum VII: length 0.42, width 0.91; abdominal mediotergite I: length 0.29, width 0.66; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 3.12: 2.41: 0.89: 0.58, middle leg: 8.77: 7.09: 3.31: 0.34, hind leg: 9.48:3.50: 0.14: 0.19.
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 chiefly blackish, without yellow markings (Figs 4G, 28G). Connexivum dorsally blackish. Mesosternum chiefly blackish with a median subtriangular yellowish spot, narrower than that of female (Fig. 28H). Abdominal venter light yellow.
LEG. Middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row (Fig. 28I).
GENITALIA. Abdominal segment VIII ventro-laterally impressed. Pygophore large, ovate. Proctiger with angular lobes laterally (Figs 6I, 28J). Paramere relatively slender, curved at basal third, distal part tapering towards hook-shaped apex (Figs 8G, 28K).
Distribution
China: Fujian, Guizhou, Hunan, Hubei, Sichuan, Yunnan (first records); Guangdong, Guangxi (Andersen & Chen 1995).
Comparative notes
Rhyacobates edentatus can be distinguished from the other species of Rhyacobates by the combination of following features of the female: the posterior part of the abdomen is curved dorsad to an oblique position, both sides of abdominal segment VII are dorsally folded mesad, almost meeting each other over the mediotergite (Fig. 28D–F), and the posterior margin of sternum VII is obtusely angled or truncate, and without posterior processes (Fig. 28E).
description: Published as part of Leng, Zhaoqi, Tran, Anh Duc & Ye, Zhen, 2023, Taxonomic review of Rhyacobates Esaki, 1923, with descriptions of three new species (Hemiptera: Heteroptera: Gerridae), pp. 1-73 in European Journal of Taxonomy 893 (1) on pages 42-47, DOI: 10.5852/ejt.2023.893.2285, http://zenodo.org/record/8385630