Rhyacobates svenhedini ( Lundblad, 1934 )

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 : 60-63

publication ID	https://doi.org/ 10.5852/ejt.2023.893.2285
publication LSID	lsid:zoobank.org:pub:D9DA4879-BC1D-4947-96E8-7D574DE334BA
DOI	https://doi.org/10.5281/zenodo.10064071
persistent identifier	https://treatment.plazi.org/id/045E878D-FFE7-2905-3A01-F8B6756D0A41
treatment provided by	Plazi
scientific name	Rhyacobates svenhedini ( Lundblad, 1934 )
status

Treatment

Rhyacobates svenhedini ( Lundblad, 1934) View in CoL

Figs 2E View Fig , 3P View Fig , 4M–N View Fig , 5O View Fig , 7F View Fig , 8L View Fig , 34 View Fig

Esakobates svenhedini Lundblad, 1934: 23–25 View in CoL , pl. 2 fig. 10 (original description).

Rhyacobates svenhedini View in CoL – 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 View Fig , 3P View Fig , 34A View Fig ); 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 View Fig ): 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 View Fig ). Male: middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 34J View Fig ); length of middle tibia ca 1.3 times length of hind tibia; proctiger relatively large, with angular lobes laterally ( Figs 7F View Fig , 34K View Fig ); paramere strongly curved at basal third, distal part slender, with hook-shaped apex ( Figs 8L View Fig , 34L View Fig ).

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 GoogleMaps • 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 GoogleMaps .

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 View Fig , 3P View Fig , 34A View Fig ). Connexivum dorsally brownish-yellow. Abdominal tergum I with a median yellow marking. Mesosternum chiefly blackish with a median subtriangular yellowish spot ( Fig. 34B View Fig ). Abdominal venter light yellow.

ABDOMEN. Abdomen relatively long, caudal part moderately curved dorsad ( Fig. 34C View Fig ). Connexival margin of abdominal segments I–II erect, of III–VII reflexed ( Fig. 34A View Fig ), meeting each other above terminal mediotergites ( Fig. 34A, D View Fig ). 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 View Fig , 34C View Fig ). Posterior margin of abdominal segment VII with four distinct processes, including two lobe-like processes on each connexival corner ( Fig. 34D–F View Fig ): 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 View Fig ).

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.

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 View Fig , 34G View Fig ). Connexivum dorsally blackish. Mesosternum chiefly blackish with a median subtriangular yellowish spot, narrower than that of female ( Fig. 34I View Fig ). Abdominal venter light yellow.

LEG. Middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 34J View Fig ).

GENITALIA. Abdominal segment VIII ventro-laterally impressed. Pygophore large, ovate. Proctiger relatively large, with angular lobes laterally ( Figs 7F View Fig , 34K View Fig ). Paramere strongly curved at basal third, distal part slender, with hook-shaped apex ( Figs 8L View Fig , 34L View Fig ).

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 View Fig , 34H View Fig ).

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 .