Rhyacobates angustus Tran & Nguyen, 2016

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 : 37

Rhyacobates angustus Tran & Nguyen, 2016

Figs 3G , 5F , 6F , 24

Rhyacobates angustus Tran & Nguyen, 2016: 502–503 , figs 1–10 (original description).

Diagnosis

Body length of apterous female 11.30 (holotype), of apterous males 7.70–8.10. Color ( Figs 3G , 24B ): dorsum of head yellow with a median longitudinal dark marking on anterior three quarters; thorax of female with a broad median yellow marking on pronotum (about one third of pronotal width), a relatively broad median yellow stripe on posterior four-fifths of mesonotum, and a median yellow marking on metanotum; thorax of male with with a narrow median yellow marking on pronotum, a narrow yellow median stripe on posterior four-fifths of mesonotum, and without yellow markings on metanotum. Female: ventral length of pregenital abdomen about two-thirds body length; connexivum of abdominal segments I–VI widened; abdominal segment VII elongate, dorso-ventrally depressed, with a pair of broad, subtriangular connexival processes ( Figs 5F , 24A ); posterior margin of sternum VII convex and widened. Male: middle trochanter without spines; small spines at basal fifth of middle femur not arranged in distinct row and those at distal four-fifths arranged in distinct row ( Fig. 24C ); length of middle tibia ca 1.6 times length of hind tibia; abdomen relatively short, posterior segments slightly curved ventrad; pygophore simple, with rounded apical margin; proctiger with rounded lobes laterally ( Fig. 6F ); paramere relatively slender, curved at basal third, slightly thicker at middle part, and apex narrow and directed mesad.

Material examined

Type specimens ( Fig. 24 )

See Tran & Nguyen (2016).

Distribution

Vietnam: Lào Cai ( Tran & Nguyen 2016).

Comparative notes

Rhyacobates angustus resembles R. zetteli , as discussed by Tran & Nguyen (2016: 503, 507–508). It is also similar to R. bui sp. nov. and R. elongatus sp. nov.; see comparative notes under R. bui .

Figures

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. 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. 24. Photographs of Rhyacobates angustus Tran & Nguyen, 2016. A–B. Holotype, apterous female (ZVNU). A. Body, lateral view. B. Habitus, dorsal view. C. Allotype, apterous male (ZVNU), habitus, dorsal view. Scale bar = 3 mm.