Rhyacobates turgidus, Leng & Tran, 2023

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 : 26-30

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.10064063
persistent identifier	https://treatment.plazi.org/id/A61745D8-0A50-4E9C-89CA-B557C637ED2E
taxon LSID	lsid:zoobank.org:act:A61745D8-0A50-4E9C-89CA-B557C637ED2E
treatment provided by	Plazi
scientific name	Rhyacobates turgidus
status	sp. nov.

Treatment

Rhyacobates turgidus sp. nov.

urn:lsid:zoobank.org:act:A61745D8-0A50-4E9C-89CA-B557C637ED2E

Figs 3C–D View Fig , 4C View Fig , 5C View Fig , 6C View Fig , 8C View Fig , 19–20 View Fig View Fig

Diagnosis

Body length of apterous females 7.82–8.50, of apterous males 5.90–6.31. In both sexes, abdominal mediotergite I distinctly swollen and large, about as long as the three subsequent abdominal terga together ( Figs 3C–D View Fig , 4C View Fig , 20A–B, H View Fig ). Female: pronotum mainly black with a median brownish-yellow spot; mesonotum and metanotum mainly black with a median brownish-yellow stripe ( Figs 3C View Fig , 19A View Fig , 20A View Fig ); abdominal mediotergite I with a median brownish-yellow stripe; abdominal terga II–VI distinctly short ( Figs 3C–D View Fig , 20A–B View Fig ); abdominal mediotergite II medially hidden beneath the abdominal mediotergite I but not laterally ( Figs 3C View Fig , 20A View Fig ); laterosternites of connexivum VII expanded dorsad, folded mesad, but not meeting in middle of abdominal dorsum; posterior margin of sternum VII with a short and pointed median process ( Fig. 20E–G View Fig ). Male: middle trochanter with one spine; middle femur with scattered small spines, not arranged in distinct row ( Fig. 20J View Fig ); length of middle tibia ca 1.4 times length of hind tibia; proctiger with angular lobes laterally ( Figs 6C View Fig , 20K View Fig ); paramere relatively slender, strongly curved at basal third, distal part tapering towards hook-shaped apex ( Figs 8C View Fig , 20L View Fig ).

Etymology

The species epithet is derived from the Latin adjective ʻturgidusʼ, meaning ʻswollenʼ and refers to the extremely large abdominal mediotergite I.

Material examined

Holotype ( Fig. 19A View Fig )

CHINA • ♀ (apterous); Sichuan Province, Lu-zhou City , He-jiang County, Tian-tang-ba; 106°15′09.5″ N, 28°35′3.6″ E; 741 m a.s.l.; 9 Aug. 2016; Chen-guang Zheng leg.; NKUM. GoogleMaps

Paratypes ( Fig. 19B View Fig )

CHINA • 3 ♁♁, 3 ♀♀ (apterous), 1 ♀ (dealated macropterous); same collection data as for holotype; NKUM GoogleMaps • 3 ♀♀ (apterous); Chongqing City, Si-mian Mountain ; 28°36′30.4″ N, 106°22′19.2″ E; 895 m a.s.l.; 10 Aug. 2016; Yan-fei Li leg.; NKUM GoogleMaps • 1 ♁, 4 ♀♀ (apterous); Sichuan Province, Lu-zhou City, Xu-yong County, Hua-gao-xi National Nature Reserve ; 28°16′19.4″ N, 105°32′27.6″ E; 741 m a.s.l.; 15 Aug. 2013; Yang Liu and Zhen Ye leg.; NKUM GoogleMaps .

Description

Apterous female

MEASUREMENTS. Body length 7.82–8.50 (holotype 8.20), width 3.01–3.60 (holotype 3.48), head width 1.48, interocular width 0.71, eye length (dorsal view) 0.43; relative lengths of antennal segments I– IV: 3.89:1.02: 1.18: 0.92; pronotum: length 0.81, width 1.65; mesonotum: length 3.78, width 3.25; metanotum: length 0.84, width 2.84; abdomen length (ventral view) 2.94; abdominal sternum VII: length 1.56, width 1.05; abdominal mediotergite I: length 0.86, width 1.71; relative lengths of leg segments (femur: tibia: tarsal segment I:tarsal segment II): fore leg: 3.94:3.38: 1.93: 0.88, middle leg: 11.12: 6.88: 4.25:0.45, hind leg: 11.35: 5.41:0.16: 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 3C View Fig , 19A View Fig , 20A View Fig ). Connexivum dorsally brownish-yellow. Abdominal mediotergite I with a median yellow stripe. Mesosternum chiefly blackish with a median subtriangular yellowish spot ( Fig. 20C View Fig ). Abdominal venter light yellow.

ABDOMEN. Abdomen relatively short, almost straight ( Fig. 5C View Fig , 20D View Fig ). Connexiva erect on abdominal segments I–VI, parallel to each other above mediotergites, reflexed over terminal mediotergites ( Fig. 20A–B View Fig ).Abdominal mediotergite I distinctly swollen, nearly as long as three subsequent abdominal terga together, sparsely covered with silvery pubescence on each side; abdominal terga II–VI distinctly short in length ( Figs 3C–D View Fig , 20A–B View Fig ). Abdominal mediotergite II medially hidden beneath abdominal mediotergite I, but laterally exposed ( Figs 3C–D View Fig , 20A View Fig ). Abdominal segment VII elongate, nearly as long as two preceding abdominal segments together, length of ventral margin distinctly longer than that of dorsal margin in lateral view ( Figs 5C View Fig , 20D View Fig ); laterosternites of connexivum VII expanded dorsad, folded mesad, not meeting in middle of abdominal dorsum ( Fig. 20E View Fig ). Abdominal sternum VII tapering caudad, posterior margin with a short and pointed median process ( Fig. 20E–F View Fig ).

Dealated macropterous female

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 3D View Fig , 20B View Fig ).

MEASUREMENTS. Body length 7.81, width 2.90, head width 1.45, interocular width 0.66, eye length (dorsal view) 0.53; pronotum: length 2.97, width 2.41; mesonotum width 2.90; metanotum: length 0.67, width 2.51; abdominal sternum VII: length 1.05, width 1.49; abdominal mediotergite I: length 0.67, width 1.19.

Apterous male

MEASUREMENTS. Body length 5.90–6.31, width 2.14–2.20, head width 1.32, interocular width 0.60, eye length (dorsal view) 0.42; relative lengths of antennal segments I–IV: 3.28: 0.92: 1.03: 0.87; pronotum: length 0.71, width 1.41; mesonotum: length 1.30, width 2.14; metanotum: length 0.71, width 1.82; abdomen length (ventral view) 1.98; abdominal sternum VII: length 0.46, width 0.83; abdominal mediotergite I: length 0.46, width 0.85; relative lengths of leg segments (femur: tibia: tarsal segment I: tarsal segment II): fore leg: 3.33: 2.88: 1.02: 0.63, middle leg: 8.72: 5.41: 2.66: 0.43, hind leg: 8.95:3.78: 0.16: 0.23.

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 black, without yellow markings ( Figs 4C View Fig , 19B View Fig , 20H View Fig ). Connexivum dorsally blackish ( Figs 4C View Fig , 19B View Fig ). Mesosternum chiefly blackish with a median subtriangular yellowish spot ( Fig. 20I View Fig ). Abdominal venter dark-yellow.

ABDOMEN. Abdomen relatively short. Abdominal mediotergite I extremely swollen ( Figs 4C View Fig , 20H View Fig ), nearly as long as three subsequent abdominal terga together.

LEG. Middle trochanter with one spine; middle femur with scattered small spines, not arranged in distinct row ( Fig. 20J View Fig ).

GENITALIA. Abdominal segment VIII ventro-laterally impressed. Pygophore large, ovate. Proctiger with angular lobes laterally ( Figs 6C View Fig , 20K View Fig ). Paramere relatively slender, strongly curved at basal third, distal part tapering towards hook-shaped apex ( Figs 8C View Fig , 20L View Fig ).

Distribution

China: Chongqing, Sichuan.

Comparative notes

Rhyacobates turgidus sp. nov. is closely related to R. recurvus and R. constrictus . These three species possess a robust body and similar outline of abdominal segment VII ( Fig. 3C, I, N View Fig ). Rhyacobates turgidus can be distinguished from R. constrictus by median yellowish stripes on the mesonotum, metanotum and abdominal mediotergite I ( Figs 3C View Fig , 20A View Fig ), which are absent in R. constrictus . Rhyacobates turgidus can be distinguished from R. recurvus by the following characteristics: (1) in lateral view, R. turgidus has a nearly straight abdomen ( Fig. 5C View Fig , 20D View Fig ), whereas R. recurvus has its abdomen curved dorsad ( Figs 5M View Fig , 31C View Fig ); (2) R. turgidus has an extremely swollen abdominal mediotergite I, which is nearly as long as the three subsequent abdominal tergites, and distinctly short abdominal terga II–VI ( Figs 3C–D View Fig , 20A–B View Fig ), whereas abdominal terga I–VI of R. recurvus are relatively normal-sized ( Figs 3N View Fig , 31A View Fig ).