Rhyacobates abdominalis Andersen & Chen, 1995

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), pp. 501-516 : 512

Rhyacobates abdominalis Andersen & Chen, 1995

Rhyacobates abdominalis Andersen & Chen, 1995: 58 –59, Figs. 12–15 (type locality: Ruyang Nat. Res., Guangdong Prov., China); Tran & Yang, 2006: 19 (record Vietnam).

Material examined. Paratypes: 1 male, 1 female (apterous), “ China: Guangdong Prov., Ruyang Nat. Res., Lao Peng Keng stream, 1100m, 14.8.1990, coll. P.P. Chen, C9012” ( NHMW). For formerly examined specimens (from Vietnam), see Tran & Yang (2006).

Size. Males, length 6.8–7.0, width 2.10–2.20 (apterous), length 6.4–6.6, width 2.06–2.11 (macropterous, dealated); females, length 9.9–10.0, width 3.50 (apterous), length 9.4–9.6, width 3.14–3.30 (macropterous, dealated).

Remarks. Rhyacobates abdominalis can be recognised by the following diagnostic characters: abdominal segment 8 of the male is ventrolaterally impressed; the proctiger of the male has a small angular projection on each side; the male paramere is slender with a broad basal part and hook-shaped apex (see Andersen & Chen 1995: Fig. 15 ); the abdomen of the female is distinctly curved dorsad, abdominal segment 7 possesses a short projection on each connexivum, and the posterior margin of sternum 7 has a sharp, small median process (see Andersen & Chen 1995: Figs. 12–14 ). The specimens of R. abdominalis from Vietnam were not significantly different compared to the paratypes from China, except for the larger size and less pointed median process of sternum 7 in the female. They were collected from the same habitat as Rhyacobates gongvo . For description notes of Vietnamese specimens, see Tran & Yang (2006: 19).

Habitats. See Tran & Yang (2006: 18, 19).

Distribution. Vietnam: Lao Cai. China: Guangdong.

Figures

FIGURES 11 – 13. (11) Habitat of type locality of Rhyacobates zetteli sp. n. (12, 13) Habitus of R. zetteli sp. n. (12) apterous male. (13) apterous female (photographed by Tran Anh Duc).

FIGURES 14 – 23. Morphological features of Rhyacobates zetteli sp. n. (14) right fore leg of female. (15) basal part of right middle leg of male, ventral view. (16) proctiger. (17, 18) left paramere, two different views. (19) endosomal sclerites. (20) body of female, lateral view. (21 – 23) apex of abdomen of female, dorsal, ventral, and lateral views respectively.