Published September 28, 2023 | Version v1
Taxonomic treatment Open

Rhyacobates anderseni Tran & Yang 2006

  • 1. Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
  • 2. Faculty of Biology, VNU University of Science, Vietnam National University, Hanoi, Nguyen Trai, Thanh Xuan, Hanoi, Vietnam.

Description

Rhyacobates anderseni Tran & Yang, 2006

Figs 3F, 4E, 5E, 6E, 8E, 23

Rhyacobates anderseni Tran & Yang, 2006: 14–16, figs 7–16, 27 (original description).

Rhyacobates anderseni – Tran & Nguyen 2016: 513 (with remarks).

Diagnosis

Body length of females 6.79–7.30, of males 6.00–6.20. Both sexes: mesonotum mainly black with a median brownish-yellow stripe (broader in female, narrower in male); metanotum chiefly blackish, without yellow markings (Figs 3F, 23A). Female: hind margin of metanotum with a pointed median process extending over abdominal tergum I (Fig. 23C–D); pronotum mainly black with a median brownish-yellow spot; posterior margin of abdominal segment VII with four processes, dorsally with a long process terminating each connexivum (Fig. 23F–G), laterally with a pair of pointed processes (Fig. 23F, H), ventrally almost truncate, without median process (Fig. 23H). Male: middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row (Fig. 23K); length of middle tibia ca 1.8–1.9 times length of hind tibia; proctiger with rounded lobes laterally (Figs 6E, 23L); paramere relatively stout and evenly curved, middle part thickened, distal part tapering towards rounded apex (Figs 8E, 23M).

Material examined

Type specimens

See Tran & Yang (2006).

Non-type specimens

CHINA • 5 ♁♁, 3 ♀♀ (apterous); Yunnan Province, Jing-hong City, Cai-yang River; 22°33′4.1″ N, 101°5′14.6″ E; 879 m a.s.l.; 30 Jul. 2016; Zhen Ye leg.; NKUM.

VIETNAM • 1 ♁ (apterous), 1 ♁ (macropterous); Hà Tĩnh Province, Vũ Quang National Park, Khe Nam Châm stream, site #1, upstream; 18°17′31.5″ N, 105°21′18.7″ E; 21 Apr. 2022; A.D. Tran et al. leg.; TAD2208; ZVNU • 1 ♀ (macropterous); same collection data as for preceding; NKUM.

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

Supplemental description

Apterous female

MEASUREMENTS. Body length 6.79–7.30, width 2.00–2.60, head width 1.32, interocular width 0.58, eye length (dorsal view) 0.59; relative lengths of antennal segments I–IV: 3:0.86: 1.21: 0.74; pronotum: length 0.73, width 1.47; mesonotum: length 2.36, width 2.54; metanotum: length 0.88, width 1.98; abdomen length (ventral view) 2.88; abdominal sternum VII: length 1.23, width 1.18; abdominal mediotergite I: length 0.15, width 0.96; relative lengths of leg segments (femur:tibia: tarsal segment I:tarsal segment II): fore leg: 3.03: 2.35:1.17:0.83, middle leg: 8.75: 5.35:2.63:0.45, hind leg: 8.85:3.08:0.15: 0.21.

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 3F, 23A). Connexivum dorsally blackish. Venter of female chiefly blackish with a median yellowish spot (Fig. 23B). Abdominal venter light yellow.

ABDOMEN. Hind margin of metanotum produced as a median protuberance over abdominal tergum I (Fig. 23C–D). Abdomen relatively short, nearly straight, moderately curved dorsad posteriorly (Figs 5E, 23E). Connexivum on abdominal segments I–VI dorsally blackish, forming a straight line in dorsal view (Figs 3F, 23A). Abdominal segment VII elongate, nearly as long as three preceding abdominal segments together (Fig. 23E), completely enclosing genital segments (Figs 3F, 23G). Posterior margin of abdominal segment VII with four processes, dorsally with a long, slender process terminating each connexivum (Fig. 23G), laterally with a pair of pointed processes (Fig. 23F, H), ventrally almost truncate, without a median process (Fig. 23H).

Apterous male

MEASUREMENTS. Body length 6.00–6.20, width 1.70–1.90, head width 1.21, interocular width 0.55, eye length (dorsal view) 0.53; relative lengths of antennal segments I–IV: 2.84: 0.89:1.14:0.78; pronotum: length 0.68, width 1.31; mesonotum: length2.13,width 1.85; metanotum:length 0.64, width 1.65;abdomen length (ventral view) 1.94; abdominal sternum VII: length 0.38, width 0.59; abdominal mediotergite I: length 0.19, width 0.68; relative lengths of leg segments (femur:tibia: tarsal segment I:tarsal segment II): fore leg: 3.04: 2.44:0.89:0.54, middle leg: 8.80: 4.86:2.38:0.36, hind leg: 8.75:2.62:0.11: 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 4E, 23I). Connexivum dorsally blackish. Metasternum anteriorly blackish and posteriorly light yellow (Fig. 23J). Abdominal venter anteriorly blackish and posteriorly light yellow or completely light yellow.

LEG. Middle trochanter without spines; middle femur with scattered small spines, not arranged in distinct row (Fig. 23K).

GENITALIA. Abdominal segment VIII ventro-laterally impressed. Pygophore large, ovate. Proctiger with rounded lobes laterally (Figs 6E, 23L). Paramere relatively stout and evenly curved, middle part thickened, distal part tapering towards rounded apex (Figs 8E, 23M).

Distribution

China: Yunnan; Vietnam: Hà Tĩnh (Tran & Yang 2006).

Comparative notes

Rhyacobates anderseni is distinct from all congeners in having a median process on the posterior margin of the metanotum in the female (Fig. 23D), which is present in three other ptilomerine genera, i.e., Andersenius, Pleciobates and Jucundus Distant, 1910. However, this species matches all other characteristics of Rhyacobates defined by Andersen & Chen (1995), as discussed by Tran & Yang (2006: 16). Future phylogenetic studies using molecular data may help to resolve the taxonomic position of this species.

Notes

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 34-36, DOI: 10.5852/ejt.2023.893.2285, http://zenodo.org/record/8385630

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Linked records

Additional details

Biodiversity

Collection code
NKUM , ZVNU
Event date
2016-07-30 , 2022-04-21
Family
Gerridae
Genus
Rhyacobates
Kingdom
Animalia
Order
Hemiptera
Phylum
Arthropoda
Scientific name authorship
Tran & Yang
Species
anderseni
Taxon rank
species
Verbatim event date
2016-07-30 , 2022-04-21
Taxonomic concept label
Rhyacobates anderseni Tran, 2006 sec. Leng, Tran & Ye, 2023

References

  • Tran A. D. & Yang C. M. 2006. New species of the water strider genera Eotrechus Kirkaldy and Rhyacobates Esaki (Heteroptera: Gerridae) from Vietnam. Raffles Bulletin of Zoology 54 (1): 11 - 20.
  • Tran A. D. & Nguyen X. Q. 2016. Three new species of the water strider genus Rhyacobates Esaki, 1923 (Hemiptera: Gerridae) from Vietnam. Zootaxa 4121 (5): 501 - 516. https: // doi. org / 10.11646 / zootaxa. 4121.5.1
  • Andersen N. M. & Chen P. P. 1995. A taxonomic revision of the Ptilomerine genus Rhyacobates Esaki (Hemiptera: Gerridae), with five new species from China and adjacent countries. Tijdschrift voor Entomologie 138: 51 - 67.