Rhyacobates lundbladi ( Hungerford, 1957 )

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 : 48-51

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.10063669
persistent identifier	https://treatment.plazi.org/id/045E878D-FFF3-2909-3A06-FBC974DF0DA2
treatment provided by	Plazi
scientific name	Rhyacobates lundbladi ( Hungerford, 1957 )
status

Treatment

Rhyacobates lundbladi ( Hungerford, 1957) View in CoL

Figs 2C View Fig , 3L View Fig , 4I View Fig , 5K View Fig , 7B View Fig , 8H View Fig , 29 View Fig

Esakobates lundbladi Hungerford, 1957: 33–36 View in CoL (original description).

Rhyacobates lundbladi View in CoL – Hungerford & Matsuda 1959: 69–72. — Matsuda 1960: 273–276, figs 659, 661, 665, 667, 669–672, 677, 679–680. — Andersen & Chen 1995: 61–62, figs 26–27 (with remarks).

Diagnosis

Body length of apterous females 11.62–12.21, of apterous males 8.02–8.41. Female: pronotum mainly black with a median brownish-yellow spot; mesonotum and metanotum mainly black with a median brownish-yellow stripe ( Figs 3L View Fig , 29A View Fig ); yellowish subtriangular marking on metanotum similar to the marking on pronotum ( Figs 3L View Fig , 29A View Fig ); posterior margin of abdominal mediotergite VII with a short median process ( Fig. 29A, D View Fig ); abdominal segment VII with four distinct processes, including two lobe-like processes on each connexival corner, consisting of one broader, posteriorly directed outer process and a narrower inner process ( Fig. 29D–F View Fig ); posterior margin of sternum VII with a small, rounded median process ( Fig. 29E View Fig ). Male: middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 29J View Fig ); length of middle tibia ca 1.5–1.6 times length of hind tibia; proctiger relatively large, with angular lobes laterally ( Figs 7B View Fig , 29K View Fig ); paramere relatively slender and sinuate, middle part thickened, distal part tapering towards narrowly rounded apex ( Figs 8H View Fig , 29L View Fig ).

Material examined

Non-type specimens

CHINA – Hunan Province • 10 ♁♁, 7 ♀♀ (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 GoogleMaps . – Jiangxi Province • 1 ♀ (apterous); Lu-shan City , Gu-ling County; 16 Jul. 1935; O. Piel leg.; IZAS • 1 ♁ (dealated macropterous); Lu-shan City , Gu-ling County; 16 Jul. 1935; O. Piel leg.; IZAS .

Supplemental description

Apterous female

MEASUREMENTS. Body length 11.62–12.21, width 2.60–3.08, head width 1.67, interocular width 0.81, eye length (dorsal view) 0.66; relative lengths of antennal segments I–IV: 5.11: 1.24: 1.67: 1.10; pronotum: length 0.91, width 1.78; mesonotum: length 2.94, width 3.34; metanotum: length 0.81, width 3.08; abdomen length (ventral view) 5.68; abdominal sternum VII: length 1.95, width 1.53; abdominal mediotergite I: length 0.52, width 1.41; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 5.28:4.51: 3.05: 1.10, middle leg: 13.71:7.95: 3.68: 0.51, hind leg: 14.10: 6.73: 0.17: 0.21.

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 3L View Fig , 29A View Fig ). Yellowish subtriangular marking on metanotum similar with the one on pronotum. Connexivum dorsally brownish-yellow.Abdominal tergum I with a median yellow marking.Mesosternum chiefly blackish with a median subtriangular yellowish spot ( Fig. 29B View Fig ). Abdominal venter light yellow.

ABDOMEN. Abdomen relatively long, sightly curved dorsad towards end ( Fig. 29C View Fig ). Connexiva erect on abdominal segments I–VI, subparallel to each other above mediotergites, reflexed over terminal mediotergites, nearly meeting each other above mediotergite VII ( Fig. 29D View Fig ). Posterior margin of abdominal mediotergite VII with a short median process. Abdominal segment VII elongate, moderately curved dorsad towards end or nearly straight, about as long as two preceding abdominal segments together ( Figs 5K View Fig , 29C View Fig ). Posterior margin of abdominal segment VII with four distinct processes, including two lobe-like processes on each connexival corner ( Fig. 29D–F View Fig ), one broader, posteriorly-directed outer lobe and the other narrower pointed inner lobe, ventrally with a small, median process ( Fig. 29E View Fig ).

Apterous male

MEASUREMENTS. Body length 8.02–8.41, width 2.00–2.60, head width 1.54, interocular width 0.83, eye length (dorsal view) 0.60; relative lengths of antennal segments I–IV: 4.12: 1.02: 1.35: 0.94; pronotum: length 0.75, width 1.66; mesonotum: length 2.33, width 2.41; metanotum: length 0.61, width 2.06; abdomen length (ventral view) 3.08; abdominal sternum VII: length 0.59, width 1.22; abdominal mediotergite I: length 0.40, width 0.87; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 4.15: 3.41: 1.38: 0.70, middle leg: 11.32: 6.44: 2.63: 0.43, hind leg: 10.71: 4.08: 0.14: 0.20.

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 with two color forms: one without ( Fig. 29G View Fig ) and the other with ( Figs 4I View Fig , 29H View Fig ) yellow marking on metanotum and abdominal tergum I. Individuals of the two types were found mixed in the same population. Connexivum dorsally blackish. Mesosternum chiefly blackish with a median subtriangular yellowish spot, narrower than that of female ( Fig. 29I View Fig ). Abdominal venter light yellow.

LEG. Middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row ( Fig. 29J View Fig ).

GENITALIA. Abdominal segment VIII ventro-laterally impressed. Pygophore large, ovate. Proctiger relatively large, with angular lobes laterally ( Figs 7B View Fig , 29K View Fig ). Paramere relatively slender and sinuate, middle part thickened, distal part tapering towards narrowly rounded apex ( Figs 8H View Fig , 29L View Fig ).

Distribution

China: Hunan (first record); Zhejiang ( Andersen & Chen 1995).

Comparative notes

Rhyacobates lundbladi is closely related to R. svenhedini due to their large body sizes, the bilobate processes on the connexival corners of abdominal segment VII and the median process on posterior margin of abdominal mediotergite VII ( Figs 3L, P View Fig , 29D View Fig , 34D View Fig ). However, R. lundbladi differs from R. svenhedini by the combination of following characteristics of the female: (1) in R. lundbladi , the subtriangular yellowish marking on metanotum is wide, with larger apex angle ( Figs 3L View Fig , 29D View Fig ), whereas in R. svenhedini , the subtriangular yellowish marking on metanotum is relatively thin, with sharp apex angle ( Figs 3P View Fig , 34D View Fig ); (2) in R. lundbladi the inner processes on the connexivum of abdominal segment VII are elongate ( Fig. 29D View Fig ), whereas that in R. svenhedini is very small ( Fig. 34D View Fig ).