Rhyacobates abdominalis Andersen & Chen, 1995

Leng, Zhaoqi, Tran, Anh Duc & Ye, Zhen, 2023, Taxonomic review of Rhyacobates Esaki, 1923, with descriptions of three new species (Hemiptera: Heteroptera: Gerridae), European Journal of Taxonomy 893 (1), pp. 1-73 : 30-34

Rhyacobates abdominalis Andersen & Chen, 1995

Figs 2A , 3E , 4D , 5D , 6D , 8D , 21–22

Rhyacobates abdominalis Andersen & Chen, 1995: 58–59 , figs 12–15 (original description).

Rhyacobates abdominalis – Tran & Yang 2006: 19 (record Vietnam). — Tran & Nguyen 2016: 512 (with remarks).

Diagnosis

Body length of apterous females 8.47–9.40, of apterous males 6.20–7.42. Female: pronotum mainly black with a median brownish-yellow spot; mesonotum and metanotum mainly black with a median brownish-yellow stripe ( Figs 3E , 21A , 22A ); abdominal segment VII dorsally with an angular process terminating each connexivum ( Figs 5D , 22C ), laterally with a pair of indistinct blunt processes, posterior margin of sternum VII with a pointed median process ( Fig. 22D–E ). Male: middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 22I ); length of middle tibia ca 1.4 times length of hind tibia; proctiger with angular lobes laterally ( Figs 6D , 22J ); paramere strongly curved at basal third, distal part slender and tapering towards hook-shaped apex ( Figs 8D , 22K ).

Material examined

Holotype ( Fig. 21A–B )

CHINA • ♀ (apterous); Guangdong Province, Ru-yuan County, Lao-Peng Stream ; 1100 m a.s.l.; 14 Aug. 1990; Ping-ping Chen leg.; NKUM .

Paratype ( Fig. 21C–D )

CHINA • 1 ♁ (apterous); same collection data as for holotype; NKUM.

Non-type specimens

CHINA – Anhiu Province • 5 ♁♁, 6 ♀♀ (apterous); Chi-zhou City, Qing-yang County, Jiu-Hua Mountain ; 30°28′43.2″ N, 117°49′25.9″ E; 20 Jul. 1994; Ping-ping Chen leg.; NKUM . – Guangdong Province • 1 ♁, 1 ♀ (apterous); Ru-yuan City, Nan-ling , Xiao-huang-shan; Jul. 2015; Zhen Ye leg.; NKUM . – Fujian Province • 1 ♁, 1 ♀ (apterous); Wu-yi-shan City, Tong-mu County, Gua-dun ; 10 Aug. 2011; Zhen Ye leg.; NKUM . – Hubei Province • 2 ♁♁, 2 ♀♀ (apterous); Shi-yan City, Huang-baixi Village ; 32°5′27.7″ N, 109°43′1.5″ E; 600 m a.s.l.; 10 Jul. 2017; Zhen Ye leg.; NKUM . – Jiangxi Province • 7 ♁♁, 11 ♀♀ (apterous); Gan-zhou City, Jiu-lian Mountain ; 24°24′59.1″ N, 114°24′53.3″ E; 500 m a.s.l.; 20 Aug. 2020; Yan-fei Li leg.; NKUM • 1 ♁, 1 ♀ (apterous); Lushan , flowing stream; Oct. 2008; C.M. Yang leg.; ZRC . – Zhejiang Province • 23 ♁♁, 13 ♀♀ (apterous); Hang-zhou City, Tian-mu Mountain ; 30°21′55.3″ N, 119°25′53.7″ E; 800 m a.s.l.; 20 Aug. 1999; Qiang Xie leg.; NKUM • 12 ♁♁, 10 ♀♀ (apterous); same collection data as for preceding; 400–600 m a.s.l.; 8 Aug. 2007; Geng-ping Zhu leg.; NKUM • 12 ♁♁, 10 ♀♀ (apterous); same collection data as for preceding; 400–600 m a.s.l.; 8 Aug. 2007; Geng-ping Zhu leg.; NKUM • 8 ♁♁, 10 ♀♀ (apterous); same collection data as for preceding; 1326 m a.s.l.; 1 Aug. 2011; Zhen Ye, Wu-hao Yang and Wen-bo Yi leg.; NKUM • 2 ♁♁, 1 ♀ (apterous); Hang-zhou City, Shun-xi ; 30°3′20.7″ N, 118°56′21.3″ E; 2 Jul. 2007; Zhong-hua Fan leg.; NKUM • 7 ♁♁, 3 ♀♀ (apterous); Jiang-shan City, Lao-fo-yan Village ; 28°21′42.6″ N, 118°41′22.1″ E; 570 m a.s.l.; 8 Aug. 2016; Min Li and Xue-shuang Ma leg.; NKUM • 4 ♁♁, 3 ♀♀ (apterous); Li-shui City, Jiu-long Mountain ; 28°21′42.6″ N, 118°41′22.1″ E; 570 m a.s.l.; 8 Aug. 2016; Min Li and Xue-shuang Ma leg.; NKUM .

VIETNAM • 1 ♀ (apterous); Lào Cai Province, Sa Pa, Cát Cát, Ho stream (feeder stream of Mường Hoa stream); 22°19′32.9″ N 103°49′52.9″ E; 27 Oct. 2020; A.D. Tran leg.; TAD20-23; ZVNU .

GPS data of previous records: see Tran & Yang (2006).

Supplemental description

Apterous female

MEASUREMENTS. Body length 8.47–9.40, width 2.90–3.30, head width 1.66, interocular width 0.71, eye length (dorsal view) 0.65; relative lengths of antennal segments I–IV: 4.50: 1.26: 1.46: 1.02; pronotum: length 0.91, width 1.84; mesonotum: length 2.71, width 3.69; metanotum: length 1.01, width 3.29; abdomen length (ventral view) 3.99; abdominal sternum VII: length 1.69, width 1.72; abdominal mediotergite I: length 0.38, width 1.19; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 4.69:4.03: 2.31: 1.04, middle leg: 12.86:7.84: 4.71: 0.43, hind leg: 13.02: 6.71: 0.21: 0.24.

C OLORATION. 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 3E , 22A ). Connexivum dorsally brownish-yellow. Abdominal mediotergite I completely yellow or with a yellow marking, covered with silver pubescence ( Fig. 3E ). Mesosternum chiefly blackish with a median subtriangular yellowish spot ( Fig. 22B ). Abdominal venter light yellow.

ABDOMEN. Abdomen relatively short, curved dorsad towards end ( Figs 5D , 22C ). Connexiva erect on abdominal segments I–VII, meeting above terminal mediotergites ( Fig. 22A ). Abdominal segment VII elongate, nearly as long as two preceding abdominal segments together ( Figs 5D , 22C ), completely enclosing genital segments ( Fig. 22D ). Abdominal segment VII dorsally with an angular process terminating each connexivum ( Fig. 22E ), laterally with a pair of indistinct blunt process, ventrally with a pointed median process on posterior margin ( Fig. 22D–E ).

Apterous male

MEASUREMENTS. Body length 6.20–7.40, width 1.90–2.20, head width 1.36, interocular width 0.58, eye length (dorsal view) 0.54; relative lengths of antennal segments I–IV: 3.41: 1.01: 1.14: 0.89; pronotum: length 0.73, width 1.42; mesonotum: length 2.09, width 2.32; metanotum: length 0.65, width 2.12; abdomen length (ventral view) 2.76; abdominal sternum VII: length 0.52, width 1.14; abdominal mediotergite I: length 0.36, width 0.83; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 3.74: 3.11: 1.10: 0.53, middle leg: 11.11: 6.38: 3.19: 0.33, hind leg: 11.18: 4.44: 0.17: 0.18.

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 with two color forms: one (i.e., paratype) with a very thin yellow median stripe ( Figs 21C , 22F ), the other without yellow markings ( Figs 4D , 22G ). Connexivum dorsally blackish. Mesosternum chiefly blackish with a median subtriangular yellowish spot, which is narrower than that of female ( Fig. 22H ). Abdominal venter light yellow.

LEG. Middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 22I ).

GENITALIA. Abdominal segment VIII ventro-laterally depressed. Pygophore large, ovate. Proctiger with angular lobes laterally ( Figs 6D , 22J ). Paramere strongly curved at basal third, distal part slender and tapering towards hook-shaped apex ( Figs 8D , 22K ).

Distribution

China: Anhui, Fujian, Hubei, Jiangxi, Zhejiang (first records); Guangdong ( Andersen & Chen 1995). Vietnam: Lào Cai ( Tran & Yang 2006).

Comparative notes

Rhyacobates abdominalis is closely related to R. chinensis , both having the hind margin of abdominal segment VII in the female with five processes. However, R. abdominalis can be distinguished from R. chinensis by having a shorter connexival process of abdominal segment VII ( Figs 22E , 25G–I ). In addition, the pair of lateral processes is inconspicuous or vestigial in R. abdominalis ( Fig. 22E ), but elongate and pointed in R. chinensis ( Fig. 25G–I ).

Figures

Fig. 2. Habitus of Rhyacobates spp. in dorsal view (females), apterous form if not stated otherwise. A. R. abdominalisAndersen & Chen, 1995.B. R. chinensis Hungerford & Matsuda, 1959.C. R. lundbladi (Hungerford, 1957). D. R. scorpio Andersen & Chen, 1995. E. R. svenhedini (Lundblad, 1934). F. R. takahashii Esaki, 1923, dealated macropterous female. Scale bar = 3 mm.

Fig. 3. Photographs of bodies of Rhyacobates spp. in dorsal view (females), apterous form if not stated otherwise.A. R. bui sp. nov. B. R. elongatus sp. nov. C. R. turgidus sp. nov., apterous form.D. R. turgidus sp. nov., dealated macropterous form.E. R. abdominalis Andersen & Chen, 1995. F. R. anderseni Tran & Yang, 2006. G. R. angustus Tran & Nguyen, 2016, holotype (ZVNU). H. R. chinensis Hungerford & Matsuda, 1959. I. R. constrictus Tran & Nguyen, 2016. J. R. edentatus Andersen & Chen, 1995. K. R. gongvo Tran & Yang, 2006. L. R. lundbladi (Hungerford, 1957). M. R. malaisei Andersen & Chen, 1995. N. R. recurvus Andersen & Chen, 1995. O. R. scorpio Andersen & Chen, 1995. P. R. svenhedini (Lundblad, 1934). Q. R. takahashii Esaki, 1923, dealated macropterous form. R. R. zetteli Tran & Nguyen, 2016. Scale bar = 3 mm.

Fig. 4. Photographs of bodies of Rhyacobates spp. in dorsal view (males), apterous form if not stated otherwise.A. R. bui sp. nov.B. R. elongatus sp. nov.C. R. turgidus sp. nov.D. R. abdominalisAndersen & Chen, 1995. E. R. anderseni Tran & Yang, 2006. F. R. chinensis Hungerford & Matsuda, 1959. G. R. edentatus Andersen & Chen, 1995. H. R. gongvo Tran & Yang, 2006. I. R. lundbladi (Hungerford, 1957). J. R. malaisei Andersen & Chen, 1995. K. R. recurvus Andersen & Chen, 1995. L. R. scorpio Andersen & Chen, 1995. M. R. svenhedini (Lundblad, 1934), apterous form. N. R. svenhedini, macropterous form. O. R. takahashii Esaki, 1923, dealated macropterous form. Scale bar = 3 mm.

Fig. 5. Photographs of bodies of Rhyacobates spp. in lateral view (apterous females). A. R. bui sp. nov. B. R. elongatus sp. nov.C. R. turgidus sp. nov.D. R. abdominalisAndersen & Chen, 1995.E. R. anderseni Tran & Yang, 2006. F. R. angustus Tran & Nguyen, 2016, holotype (ZVNU). G. R. chinensis Hungerford & Matsuda, 1959. H. R. constrictus Tran & Nguyen, 2016. I. R. edentatus Andersen & Chen, 1995. J. R. gongvo Tran & Yang, 2006. K. R. lundbladi (Hungerford, 1957). L. R. malaisei Andersen & Chen, 1995. M. R. recurvus Andersen & Chen, 1995. N. R. scorpio Andersen & Chen, 1995. O. R. svenhedini (Lundblad, 1934). P. R. takahashii Esaki, 1923. Q. R. zetteli Tran & Nguyen, 2016. Scale bar = 3 mm.

Fig. 6. Proctiger of Rhyacobates spp. in dorsal view (males). A. R. bui sp. nov. B. R. elongatus sp. nov. C. R. turgidus sp. nov. D. R. abdominalis Andersen & Chen, 1995. E. R. anderseni Tran & Yang, 2006. F. R. angustus Tran & Nguyen, 2016. G. R. chinensis Hungerford & Matsuda, 1959. H. R. constrictus Tran & Nguyen, 2016. I. R. edentatus Andersen & Chen, 1995. Scale bar = 0.2 mm.

Fig. 8. Paramere of Rhyacobates spp. in lateral view. A. R. bui sp. nov. B. R. elongatus sp. nov. C. R. turgidus sp. nov. D. R. abdominalis Andersen & Chen, 1995. E. R. anderseni Tran & Yang, 2006. F. R. chinensis Hungerford & Matsuda, 1959. G. R. edentatus Andersen & Chen, 1995. H. R. lundbladi (Hungerford, 1957). I. R. malaisei Andersen & Chen, 1995. J. R. recurvus Andersen & Chen, 1995. K. R. scorpio Andersen & Chen, 1995. L. R. svenhedini (Lundblad, 1934). M. R. takahashii Esaki, 1923. Scale bar = 0.2 mm.

Fig. 21. Photographs of Rhyacobates abdominalis Andersen & Chen, 1995 and relevant labels. A–B. Holotype, apterous female (NKUM). A. Habitus, dorsal view. B. Labels. C–D. Paratype, apterous male (NKUM). C. Habitus, dorsal view. D. Labels. Scale bar: A, C = 3 mm.

Fig. 22. Morphological features of Rhyacobates abdominalis Andersen & Chen, 1995. 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, lateral view. F–G. Body of male, dorsal view. H. Body of male, excluding head and prothorax, ventral view. I. Basal part of right middle leg of male, ventral view. J. Proctiger of male, dorsal view. K. Left paramere, lateral aspect, two different views. Scale bars: A–I = 1 mm; J–K = 0.2 mm.

Fig. 25. Morphological features of Rhyacobates chinensis Hungerford & Matsuda, 1959. A. Body of female, dorsal view. B. Body of female, excluding head and prothorax, ventral view. C–D. Abdominal end of female, ventral view. E–F. Body of female, apterous form (E, excluding head and prothorax) and dealated macropterous form (F), lateral view. G–I. Abdominal end of female, lateral view. J. Body of male, dorsal view. K. Body of female, excluding head and prothorax, ventral view. L. Basal part of right middle leg of male, ventral view. M. Proctiger of male, dorsal view. N. Left paramere, lateral aspect, two different views. Scale bars: A–L = 1 mm; M–N = 0.2 mm.