Rhagovelia caudata, X.Q. & A.D., 2016

X. Q., Nguyen & A. D., Tran, 2016, Descriptions of two new species of Rhagovelia (Heteroptera: Gerromorpha: Veliidae) from Vietnam, Raffles Bulletin of Zoology 64, pp. 389-396 : 389-392

Rhagovelia caudata , new species

Department of Invertebrate Zoology, Faculty of Biology, Hanoi University of Science ( Vietnam National University, Hanoi), 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam; Email: [e-mail] (NXQ); [e-mail] (* corresponding author; TAD).

( Figs. 1, 2 , 5–15 )

Material examined. Holotype (apterous male) and allotype (apterous female): VIETNAM, Nghe An Prov., Ky Son, Ta Ca, feeder stream of Loi stream, coll. Tran A.D. & Nguyen V.H., 16 April 2013, TAD1302 ( ZMHU). Paratypes: VIETNAM: Nghe An Prov.: 6 males, 1 female (apterous), 3 males, 7 females (macropterous), same locality data as holotype ( ZMHU); 2 males, 1 female (apterous), Pu Mat N’Park, Khe Kem waterfall & stream, site #1, coll. Ngo Q.H., 20 December 2012, NQH1203 ( ZMHU); 1 male (apterous), Con Cuong, near Tung Huong, Khe Num stream, coll. Ngo Q.H., 21 December 2012, NQH1211 ( ZMHU). Dien Bien Prov.: 7 males, 15 females (apterous), Muong Phang, Muong Phang stream, coll. Tran A.D., 26 July 2004, DY0415 ( ZRC); 6 males, 7 females (apterous), National Rd 6, km9 to DBP city, a stream on road side, coll. Tran A.D., 26 July 2004, DY0416 ( ZRC); 3 males, 2 females (apterous), 1 male (macropterous), upstream and waterfall of Muong Phang stream, coll. Tran A.D., 28 July 2004, DY0419 ( ZRC); female (apterous), no name stream northeastern side, near DBP City, coll. Tran A.D., 29 July 2004, DY0420 ( ZRC). Lai Chau Prov.: 3 males, 1 female (apterous), 2 males, 1 female (macropterous), Muong Te, Bum Nua, a stream by the road from Muong Te town to Pa Tan, ca. 13 km from Muong Te town , coll. Tran A.D. et al., 2 June 2013, TAD1328 ( ZMHU); 3 females (apterous), Muong Te, Muong Mo stream, by the road from Muong Te town to Lai Ha, ca. 33 km from Muong Te town , coll. Tran A.D. et al., 3 June 2013, TAD1329 ( ZMHU); 1 male (macropterous), Muong Te, Muong Mo, Ban 41 stream, by the road from Muong Te town to Lai Ha, ca. 45 km from Muong Te town , coll. Tran A.D. et al., 3 June 2013, TAD1330 ( ZMHU). Ha Giang Prov.: 1 male, 3 females (macropterous), Yen Minh, Na Khe commune, stream near Nat’ road 4C, coll. Tran A.D. et al., 8 May 2014, TAD1404 ( ZMHU). Phu Tho Prov.: 2 males, 2 females (apterous), Xuan Son N’Park, Lap stream, site 1, at Ngoc waterfall, coll. Tran A.D. et al., 5 June 2013, TAD1331 ( ZMHU); 1 male, 1 female (apterous), Xuan Son N’Park, Lap stream, site 2, first concrete bridge from Ngoc waterfall, coll. Tran A.D. et al., 5 June 2013, TAD1332 ( ZMHU); 1 female (apterous), Xuan Son N’Park, Kim Thuong, Tan Ong stream, site 2, ca. 2 km from Chin Tang waterfall, coll. Tran A.D. et al., 6 June 2013, TAD1335 ( ZMHU); 3 males, 2 females (apterous), Xuan Son N’Park, Kim Thuong, Tan Ong stream, site 2, ca. 2 km from Chin Tang waterfall, coll. Tran A.D. et al., 28 August 2013, TAD1341 ( ZMHU); 1 male (apterous), Xuan Son N’Park, Kim Thuong, Tan Ong stream, site 3, ca. 4 km from Chin Tang waterfall, coll. Tran A.D. et al., 28 August 2013, TAD1342 ( ZMHU); 2 females (apterous), Xuan Son N’Park, Dong Son, Than stream, site 1, coll. Tran A.D. et al., 29 August 2013, TAD1346 ( ZMHU); 4 males, 9 females (apterous), Xuan Son N’Park, Ban Coi, Coi stream, site 1, water from underground, coll. Tran A.D. et al., 29 August 2013, TAD1349 ( ZMHU, NHMW); 2 males (apterous), Xuan Son N’Park, Ban Coi, Coi stream, site 2, near bridge, coll. Tran A.D. et al., 29 August 2013, TAD1350 ( ZMHU). Thanh Hoa Prov.: 1 male, 3 females (apterous), Ben En N’Park, Nhu Xuan, La Rong stream, coll. Pham T.D., 03 August 2012, BE1204 ( ZMHU).

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ISSN 2345-7600 (electronic) | ISSN 0217-2445 (print)

Description. Size: Apterous males: body length 2.47–2.75 (holotype: 2.69), width 1.08–1.14 (holotype: 1.12); apterous females: length 2.66–3.00 (allotype: 2.81), width 1.08–1.26 (allotype: 1.23); macropterous males: length (without wings) 2.56–2.78, width 1.19–1.21; macropterous females: length (without wings) 2.81–2.97, width 1.17–1.26.

Colour ( Figs. 1, 2 ): body mainly black; antennal segment 1 mostly light yellowish, at most only orange brown at distal third; antennal segments 2–4 variable, orange brown to dark brown; juga light yellowish, anteclypeus and rostrum yellowish to brown; pronotum anteriorly with large median transverse orange band (width about half of pronotum width, median length about two thirds of pronotum length); pro-, meso- and metacetabula apically orange brown or black; all coxae and trochanters light yellowish; profemur light yellowish at least at proximal half, distal part variable, brown to black; basal fifth of dorsal side and all ventral side of metafemur yellowish; mesofemur, tibiae and tarsi of all legs variable, mostly orange-brown to black, ventral side usually lighter, mostly orange-brown; apex of abdomen of both sexes (in males: segments 8 and genitalia; in females: posterior of segment 7 and genitalia) orange to orange-brown.

Pilosity: body with short, appressed golden pubescence; dorsum of head, propleura, and mesopleura with numerous long, erect brown or black setae; mesosternum with long yellowish hairs forming inverted V-shaped patch running towards posterior margin; metasternum and venter of abdomen with scattered long yellowish hairs; antennae and legs with scattered long brown or black setae.

Apterous male: Head length 0.31, width 0.75, eye length 0.29. Lengths of antennal segments 1–4: 0.63, 0.32, 0.47, 0.43. Juga mostly smooth, with spicules at posterior margin; thoracic sterna and pleura with scattered black spicules, more densely distributed on pro- and mesoepisterna. Pronotum short, median length 0.19; mesonotum length 0.56, about 2.9 times length of pronotum; metanotum length 0.09. Lengths of leg segments (femur, tibia, tarsus 1+2+3): fore leg: 0.72, 0.79, 0.02+0.02+0.20; middle leg: 1.17, 0.97, 0.04+0.34+0.59; hind leg: 0.90, 1.05, 0.04+0.05+0.26. Meso-, and metacoxa with some black spicules dorsally. Ventral surface of all coxa without spicules. Mesotrochanter with some black spicules dorsally. Metatrochanter with some black spicules dorsally and 2–3 small black denticles (three in holotype) ventro-distally. Mesofemur ( Fig. 5 ) with a row of about nine stiff setae along ventral surface. Metafemur ( Figs. 6, 7 ) incrassate, length about 3.1 times width (width measured without teeth: 0.29), ventral surface armed with a row of teeth starting from the longest tooth in the middle, followed by nine teeth gradually decreasing in length towards apex of metafemur, and some black granules arranged in a row nearly parallel to the row of femoral teeth, running from base to apex of metafemur. Metatibia ( Fig. 6 ) slender and straight, with a row of short teeth on inner side.

Abdominal segments gradually narrowed towards apex; tergites 1–5 subequal in length (0.14–0.16), tergite 6 slightly longer (0.18), tergite 7 clearly longer (0.26) than each of preceding tergite; tergite 7 length 0.8 times of width, raised posteriorly in lateral view ( Fig. 9 ); abdominal sternites 2, 3 weakly carinate medially; sternite 7 slightly shining; both ventral and dorsal abdominal segment 8 shining. Genital segments: small and weakly modified; segment 8 small, subcylindrical; pygophore subovate, posterior margin slightly produced medially; proctiger ( Fig. 10 ): proximal half with broadly rounded lateral lobes, distal half setiferous; paramere ( Fig. 11 ) slender distally, curved at apex, lateral surface set with many long setae.

Apterous female: Pilosity similar to that in males, except setae in ventral row of mesofemur less stiff, and connexiva with golden pubescence directed caudad. Hind leg ( Fig. 8 ): metatrochanter without black denticles, metafemur slightly less incrassate, length about 3.7 times width (width 0.22), and with ventral row of teeth slightly less prominent (one large teeth in the middle, followed by five shorter teeth distally), without or with very few (1–2) granules; metatibia straight, inner side without armature.

Abdomen ( Figs. 12–14 ): connexiva evenly and moderately converging posteriorly ( Fig. 12 ); laterotergites sloped latero-dorsad; tergites 1–4 subequal in length (0.15–0.16), tergites 5–8 longer, length as follows: 0.19, 0.23, 0.27, 0.23; tergite 7 about as long as wide; tergite 8 shorter than wide, with posterior margin straight; tergite 8 and sternite 7 on ventral area shining; in lateral view, connexivum posteriorly produced into small sub-triangular process bearing a tuft of setae ( Fig. 13 ); posterior margin of sternite 7 almost straight ( Fig. 14 ); gonocoxa simple, plate-like, mainly exposed; proctiger small, relatively slender, directed straight caudad. Other structural characteristics similar to males.

Macropterous males: Pronotum large, with prominent humeri. Forewing ( Fig. 15 ) with three closed cells, the single distal cell small. In some specimens, metatrochanter without black denticles. Metafemur slightly more slender than that in apterous males. Other characteristics similar to apterous males.

Macropterous females: Pronotum and forewing similar to those of macropterous males. Other characteristics similar to apterous females.

Etymology. The word caudata refers to the orange to orangebrown apex of abdomen in both sexes.

Comparative notes. Rhagovelia caudata , new species can be assigned to the R. sarawakensis species group (sensu Polhemus & Polhemus, 1988), in having short pronotum (median length shorter than eye length, and about one third of mesonotal length), forewing with three closed cells, long paramere with distal hook, and abdominal terminalia in both sexes simple, without special modification. It is, however, distinctly different from all other taxa in the R. sarawakensis species group, in having more incrassate hind femur with only a distal row of teeth and without the proximal row of teeth, the extensive yellow-orange base of femora, and the orange-brown abdominal terminalia in both sexes. In other species of the R. sarawakensis group, hind femur is slender, with both proximal and distal rows of teeth, femora are mostly black or at least dark brown, and abdominal terminalia usually black. Other diagnostic characters of R. caudata , new species include the shape of proctiger ( Fig. 10 ), the paramere ( Fig. 11 ), and shape of abdominal apex of female ( Figs. 12–14 ).

Distribution. Vietnam (northern): Dien Bien, Lai Chau, Ha Giang, Phu Tho, Thanh Hoa, Nghe An.

Figures

Figs. 1–4. Habitus of two new species of Rhagovelia (paratypes). 1, 2, Rhagovelia caudata, new species; 3, 4, Rhagovelia bisinuata, new species; 1, 3, apterous males; 2, 4, apterous females, all of same scale.

Figs. 5–15. Rhagovelia caudata, new species. 5, right mesofemur of male; 6, right hind leg of male; 7, right metafemur of male, posterior view; 8, right metafemur of female; 9, apex of abdomen of male, lateral view; 10, proctiger of male; 11, left paramere; 12, abdomen of female, dorsal view; 13, 14, apex of abdomen of female, lateral view (13) and ventral view (14); 15, right forewing of male. (5–8 same scale; 12–15 same scale).