Rhyacobates gongvo Tran & Yang, 2006

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 : 513

Rhyacobates gongvo Tran & Yang, 2006

( Figs. 41, 42 )

Rhyacobates gongvo Tran & Yang, 2006: 16 –19, Figs. 17–25 , 28 (type locality: Sa Pa, Lao Cai Prov., Vietnam).

Material examined. For holotype and paratypes, see Tran & Yang (2006).

Others: VIETNAM: Lao Cai Prov.: 1 female (apterous), Sa Pa, Nam Sai, Seo Nam Sai stream 1, 22°15.761’N 103°55.909’E, 844 m asl., coll. Dinh N.H. et al., 24 October 2012, DNH12.09 ( ZMHU); 1 female (apterous), Sa Pa, Nam Sai, Seo Nam Sai stream 2, 22°14.67’N 103°59.541’E, 469 m asl., coll. Dinh N.H. et al., 24 October 2012, DNH12.10 ( ZNHU); 6 males, 5 females (apterous), 2 males (macropterous, de-alated), Sa Pa, Ban Ho, Ban Den, Nam Pu stream (feeder stream of Muong Hoa stream), 22°15.709’N 103°58.054’E, 416 m asl., coll. Tran A.D. et al., 29 May 2013, TAD1316 ( ZMHU); 1 male, 2 females (apterous), Sa Pa, Thanh Phu, Nam Cang stream, 22°15.401’N 103°58.866’E, 398 m asl., coll. Tran A.D. et al., 26 October 2013, TAD1359 ( ZMHU); 13 males, 4 females (apterous), Sa Pa, Ban Ho, Nam Pu stream (feeder stream of Muong Hoa stream), site 1, at lower section, 22°15.778’N 103°58.270’E, 404 m asl., coll. Tran A.D. et al., 26 October 2013, TAD1361 ( ZMHU); 1 female (apterous), Sa Pa, Cat Cat, Ho stream (feeder stream of Muong Hoa stream), 22°19.546’N 103°49.880’E, 1233 m asl., coll. Tran A.D. et al., 27 October 2013, TAD1366 ( ZMHU).

Size. Males, length 6.2–6.5 (allotype 6.5), width 1.88–2.20 (apterous), length 6.4, width 1.97 (macropterous, de-alated); females, length 7.8–8.3 (holotype 8.3), width 2.52–2.67 (holotype 2.52) (apterous), length 7.5, width 2.44 (macropterous, de-alated).

Remarks. Rhyacobates gongvo differs from other species of Rhyacobates by the following diagnostic characteristics: in the apterous morph, the mesonotum has a median yellow stripe on the posterior three quarters; the male proctiger has small angular projections on each side (see Tran & Yang 2006: Fig. 22 ); the male paramere is relatively long and slender, not setose (see Tran & Yang 2006: Figs. 24, 25 ); the abdomen of the female is elongate and straight (length about 0.4 times body length), the posterior part of sternum 7 is slightly depressed dorsoventrally (see Tran & Yang 2006: Fig. 17 ); sternum 7 of the female does not totally enclose the genital segments, the posterior margin is straight and without a process, and the connexival projections are long, straight, and flat (see Tran & Yang 2006: Figs. 18–20 ). Rhyacobates gongvo is relatively similar to R. malaisei Andersen & Chen, 1995 , but can be separated from the latter by the diagnosis above (for a comparison between these two species, see Tran & Yang 2006: 18–19).

Habitats. See Fig. 40 ; also see Tran & Yang (2006: 18).

Distribution. Vietnam: Lao Cai.

Figures

FIGURES 40 – 42. (40) Habitat of Rhyacobates angustus sp. n. and R. gongvo. (41) Apterous female of R. gongvo resting on the exposed rock in the middle of the stream. (42) School of adults and nymphs of R. gongvo on the exposed rock in the middle of the stream (40: photographed by Nguyen Thanh Son; 41, 42: 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.

FIGURES 24 – 26. (24) Habitat of type locality of Rhyacobates constrictus sp. n. (25) A copulating pair of R. constrictus sp. n., skating on the fast current of the stream. (26) A copulating pair of R. constrictus sp. n., resting on the emerged rocks in the middle of the stream (photographed by Tran Anh Duc).

FIGURES 27 – 39. Morphological features of Rhyacobates constrictus sp. n. (27) right fore leg of female. (28) basal part of right middle leg of male, ventral view. (29) proctiger. (30 – 32) left paramere from three different views. (33) endosomal sclerites. (34) body of female, lateral view. (35) apex of abdomen of female, lateral view. (36) abdomen of female holotype, dorsal view. (37) apex of abdomen of female holotype, ventral view. (38, 39) apex of abdomen of female paratype, dorsal and ventral view.