DSpace at VNU: Notes on the subfamily Ranatrinae (Hemiptera: Nepidae) from Vietnam, with two new species of Ranatra Fabricius, 1790

Journal of Asia-Pacific Entomology 19 (2016) 515–523 Contents lists available at ScienceDirect Journal of Asia-Pacific Entomology journal homepage: www.elsevier.com/locate/jape Notes on the subfamily Ranatrinae (Hemiptera: Nepidae) from Vietnam, with two new species of Ranatra Fabricius, 1790 A.D Tran ⁎ & V.V Nguyen Department of Invertebrate Zoology, Faculty of Biology, Hanoi University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Thanh Xuan, Hanoi, Vietnam a r t i c l e i n f o Article history: Received 16 March 2016 Revised May 2016 Accepted 14 May 2016 Available online 15 May 2016 Keywords: Ranatra Cercotmetus Nepidae New species a b s t r a c t Two new species Ranatra nieseri sp.n and Ranatra bilobata sp.n are described Distribution records of Ranatra and Cercotmetus of the subfamily Ranatrinae (Hemiptera: Nepidae) in Vietnam are provided Ranatra parmata Mayr, 1865 is recorded from Vietnam and China (Hainan island) for the first time In addition, this paper provides the first record of Ranatra libera Zettel, 1999 from Thailand © 2016 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society Published by Elsevier B.V All rights reserved Introduction The family Nepidae is a worldwide taxon with over 270 known species in 15 genera, attaining its highest species richness in the tropical regions of the southern hemisphere (Polhemus and Polhemus, 2008) They are true aquatic bugs, characterised by elongated body, the raptorial fore legs and long respiratory siphon at the abdominal end (Chen et al., 2005; Polhemus and Polhemus, 2013) They are usually found living in standing waters, such as small pools, ponds, lakes, or in running waters but only in sections of slower currents, like near the edges of the stream This family contains two subfamilies, Ranatrinae (commonly known as water stick insects) and Nepinae (commonly known as water scorpions) Species of the subfamily Ranatrinae have long, slender, cylindrical or subcylindrical bodies (body length ranging from 11 to 60 mm) and long and slender legs This subfamily contains two genera, Cercotmetus Amyot & Seville, 1843 and Ranatra Fabricius, 1790 Lansbury (1973) revised Cercotmetus, which occurs in Asia and Australia, and recognised nine species Keffer and Polhemus (1999) described the tenth species, Cercotmetus minutus from Laos Ranatra is a pantropical genus, with over 120 currently recognised species, of which 54 occur in the Old World (Polhemus and Polhemus, 2013) The Ranatra of Southeast Asia was revised by Lansbury (1972) Subsequent studies, e.g., by Nieser and Chen (1991, 1996), Nieser (1996, 1997), Zettel (1999), Chen et al (2004) and Tran and Polhemus (2012), have provided descriptions of further new species and subspecies ⁎ Corresponding author E-mail addresses: tran.anhduc@hus.edu.vn (A.D Tran), vinhnv@hus.edu.vn (V.V Nguyen) For the Ranatrinae of Vietnam, prior to this study, eight species have been reported, including three of Cercotmetus and five of Ranatra, all by Lansbury (1972, 1973) in his revisions of respective genera Tran and Polhemus (2012) provided additional distribution records of Ranatra thai Lansbury, 1972, including records in Vietnam Those records were merely incidental based on old collections available, thus the nepid fauna of Vietnam has still been inadequately explored and under estimated Based on collections from our recent field surveys (2013–2015) and previous collections in Vietnam, we have identified a number of samples belonging to various taxa, including two undescribed species and Ranatra parmata Mayr, 1865, which is the first record for Vietnam In the present paper, we describe these new species and provide a species list with additional distribution records of other species of Ranatrinae found in Vietnam and neighbouring areas Materials and methods The specimens examined in this study are deposited in the Zoological Collection of the Biological Museum (ZMHU) in Hanoi University of Science (Vietnam National University, Hanoi) and the Zoological Reference Collection (ZRC) of the Lee Kong Chian Natural History Museum (National University of Singapore) Terminology and methods follow previous taxonomic works on Nepidae by Lansbury (1972, 1973), Chen et al (2005) and Polhemus and Polhemus (2013) If no variation is given (in range), measurements refer to the holotype or a randomly selected specimen Binocular microscopes and compound microscopes with camera lucida were used to prepare descriptions and line drawings All measurements in the descriptions below are given in millimeters http://dx.doi.org/10.1016/j.aspen.2016.05.006 1226-8615/© 2016 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society Published by Elsevier B.V All rights reserved 516 A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 Taxonomy Subfamily RANATRINAE Douglas & Scott, 1865 Cercotmetus Amyot & Seville, 1843 Cercotmetus asiaticus Amyot & Seville, 1843 Cercotmetus asiaticus Amyot & Serville, 1843: 441 Material examined VIETNAM: Ha Giang Prov.: male, female, Bac Me, Minh Ngoc commune, small stream by Nat' road 34 ca 20 km to Bac Me town, 22°46.487′N 105°11.229′E, 148 m asl., coll Tran A.D et al., 07 May 2014, TAD1401 (ZMHU); female, nymphs, Yen Minh, Na Khe commune, stream near Nat' road 4C, vic 23°10.652′N 105°02.026′E, 500 m asl., coll Tran A.D et al., 08 May 2014, TAD1404 (ZMHU) Bac Kan Prov.: male, female, Bach Thong, Duong Phong commune, Ban Pe, Cau river, coll Tran, A.D et al., 24 Aug 2012, TAD1224 (ZMHU) Dien Bien Prov.: male, female, nymphs, Nam Rom river, 10 km to Dien Bien Phu City, 21°26.920′N 103°02.936′E, 669 m asl., coll Tran A.D., 25 Jul 2004, DY0413 (ZRC) Phu Tho Prov.: male, Xuan Son N′Park, Dong Son, Than stream, site 2, 21°11.234′N 104°52.383′E, 234 m asl., coll Tran A.D et al., 29 Aug 2013, TAD1347 (ZMHU) Hanoi: male, nymphs, Ba Vi N′Park, stream near Coste 400, vic 21°04.767'N 105° 21.979'E, ca 550 m asl., coll Ngo Q.H et al., 16 Dec 2011, TAD1120 (ZMHU); male, Ba Vi N′Park, Khanh Thuong, Bang stream, 21°01.870′N 105°21.545′E, 83 m asl., coll Ngo Q.H et al., 17 Dec 2011, TAD1122 (ZMHU); males, female, Khanh Thuong, Mit stream, forest area, 21°01.898′N 105°21.310′E, 80 m asl., coll Ngo Q.H et al., 17 Dec 2011, TAD1124 (ZMHU); females, Ba Vi N′Park, Khoang Xanh, Tien stream, 21°02.667′N 105°23.557′E, 95 m asl., coll Ngo Q.H et al., 17 Dec 2011, TAD1127 (ZMHU); males, females, Khanh Thuong, Mit stream, forest area, 21°01.898′N 105°21.310′E, 80 m asl., coll Ngo Q.H & Tran A.D., 26 Apr 2012, TAD1203 (ZMHU) Thanh Hoa Prov.: male, females, nymphs, Ben En N'Park, Ngon stream, coll Pham T.D., 02 Aug 2012, BE1203 (ZMHU); male, Ben En N'Park, Nhu Xuan, La Rong stream, coll Pham T.D., 03 Aug 2012, BE1204 (ZMHU); male, Ben En N'Park, Ngon stream, near Bang ranger station, coll Pham T.D., 03 Aug 2012, BE1205 (ZMHU); male, Pu Hu Nature Reserve, Muong Lat, Trung Ly, Co Luong, Cha Lan stream, coll Pham T.D., 04 Apr 2013, PH1301 (ZMHU); male, Pu Luong Nature Reserve, Quan Hoa, Phu Nghiem, Dong Tam, Luong stream, coll Pham T.D., 15 Mar 2013, PL1301 (ZMHU); males, females, Pu Luong Nature Reserve, Ba Thuoc, Co Lung, Ban Khuyn, Khuyn stream, coll Pham T.D., 18 Mar 2013, PL1303 (ZMHU) Nghe An Prov.: females, Pu Mat N′Park, Khe Kem stream, site #3, 18°57.683′N 104°48.224′E, 396 m asl., coll Ngo Q.H., 20 Dec 2012, NQH1205 (ZMHU); males, female, Pu Mat N′Park, Khe Kem stream, site #4, 18°56.334′N 104°48.357′E, 348 m asl., coll Ngo Q.H., 20 Dec 2012, NQH1206 (ZMHU); males, females, Pu Mat N′Park, Khe Kem stream, site #5, 18°58.126′N 104°50.139′E, 170 m asl., coll Ngo Q.H., 20 Dec 2012, NQH1207 (ZMHU); male, female, Pu Mat N′Park, Khe Kem stream, site #6, 18°58.656′N 104°50,162′ E, 154 m asl., coll Ngo Q.H., 20 Dec 2012, NQH1208 (ZMHU); female, Con Cuong, Lien Huong village, Khe Thoi stream, 19°05.430′N 104°39.444′N, 106 m asl., coll Ngo Q.H., 21 Dec 2012, NQH1209 (ZMHU); males, females, nymph, Con Cuong, Tung Huong village, Khe Thoi stream, 19°05,357′N, 104°40.031′E, 100 m asl., coll Ngo Q.H., 21 Dec 2012, NQH1210 (ZMHU); female, Ky Son, Nat' road km191 + 572, stream at Ban Ba bridge, coll Tran A.D et al., 16 Apr 2013, TAD1304 (ZMHU); female, Con Cuong, Nat' road 7, Chi Khe commune, stream at Khe Chai bridge, coll Tran A.D et al., 17 Apr 2013, TAD1308 (ZMHU); male, female, Pu Mat N′Park, Khe Kem stream, site #4, coll Tran A.D et al., 18 Apr 2013, TAD1313 (ZMHU) Ha Tinh Prov.: male, Huong Son, coll Cao T.K.T., Dec 2003 (ZRC) Quang Binh Prov.: males, nymphs, Phong Nha N'Park, Suoi Cha Ang, coll Hoang Q.K & Dinh V.K., Aug 2002, VNQB0204 (ZRC); male, Phong Nha N'Park, Km19 National Rd 20, Suoi Cha Ang, coll Tran A.D, 12 Aug 2001, VNQB0102 (ZRC); males, females, Phong Nha N'Park, Khe Gat, Cha Noi, coll Hoang Q.K & Dinh V.K., Apr 2003, VNQB0301 (ZRC); male, females, nymphs, Phong Nha, Cha Noi, Khe Con Khai stream, 17°38.196′N 106°05.928′E, 263 m asl., coll Tran A.D., 13 Jul 2004, DY0402 (ZRC); male, females, nymphs, Phong Nha, Vuc Tro stream, 17°38.188′N 106°12.810′E, 34 m asl., coll Tran A.D., 14 Jul 2004, DY0404 (ZRC); male, female, nymph, Phong Nha, a stream near Forest Ranger station 37, 17°31.395′N 106°17.716′E, 86 m asl., coll Tran A.D., 15 Jul 2004, DY0405 (ZRC); females, Phong Nha, Chay stream, 17°33.146′N 106°14.425′E, 94 m asl., coll Tran A.D., 17 Jul 2004, DY0410 (ZRC) Dong Nai Prov.: male, female, nymph, Nam Cat Tien, Kra river, 11°21.462′N 107°12.035′E, 120 m asl., coll Tan H.H et al., 10 May 2001, THH0127 (ZRC); male, Nam Cat Tien, Lan stream B, 11°21.242′N 107°11.893′E, 125 m asl., coll Tan H.H et al., 10 May 2001, THH0128 (ZRC); males, nymph, Nam Cat Tien, Lan stream A, 11°21.018′N 107°11.645′E, 90 m asl., coll Tan H.H et al., 10 May 2001, THH0129 (ZRC); male, nymph, Vinh Cuu, Hieu Liem, Ma Da stream, 11°15.013′N 106°55.919′E, 27 m asl., coll Tran A.D., May 2003, TAD0313 (ZRC); female, Vinh Cuu, Vinh An, Da Kin stream, 11°24.600′N 107°06.557′E, 88 m asl., coll Tran A.D., 11 May 2003, TAD0317 (ZRC); male, females, Cat Tien N'Park, C10 stream, coll Tran A.D & Pham T.D., 10 Apr 2010, PTD1005 (ZMHU); female, Vinh Cuu, Vinh An, Rang stream, coll Tran A.D., 20 Apr 2009, TAD0913 (ZMHU); female, Vinh Cuu, Ma Da stream, near Rang Rang forest ranger station, ca 400 m down-stream from bridge, coll Pham T.D., 13 Apr 2010, PTD1007 (ZMHU) CHINA: Hainan Prov.: male, female, nymphs, Baoting, Lingshui river basin; stream along road before Bacun, coll I-S Chen et al., 10 Sep 2005, THH05–71 (ZRC) THAILAND: male, female, Salween Basin, Mae Nam Moi, coll S.H Tan et al., 19 Mar 1996, TG2 (ZRC) Distribution Vietnam: Ha Giang, Bac Kan, Dien Bien, Phu Tho, Hanoi, Thanh Hoa, Nghe An, Ha Tinh, Quang Binh, Gia Lai, Dong Nai Other countries: Myanmar, Thailand, Peninsular Malaysia, Singapore, Java, Sumatra, Borneo (Lansbury, 1973; Nieser and Polhemus, 1998; Polhemus and Polhemus, 2013), China: Yunnan (Chen et al., 2004), Hainan island (first record) Cercotmetus brevipes Montandon, 1903 Cercotmetus brevipes Montandon, 1909: 65 Cercotmetus formosanus Sonan, 1928: 377 (synonymised by Lansbury, 1973: 92) Material examined VIETNAM: Quang Binh Prov.: female, nymph, Phong Nha N'Park, Khe Gat, Khe Sen, coll Hoang Q.K & Dinh V.K., Apr 2003, VNQB0302 (ZRC); Dong Nai Prov.: female, Nam Cat Tien, Muoi Que stream, 11°28.228′N 107°20.377′E, 130 m asl., coll Tan H.H et al., May 2001, THH0121 (ZRC); females, Nam Cat Tien, Tra river, 11°22.987′N 107°21.757′E, 130 m asl., coll Tan H.H et al., 11 May 2001, THH0130 (ZRC); female, Cat Tien N'Park, Dong Nai river, Thac Troi, coll Tran A.D., 12 Apr 2009, TAD0908 (ZMHU); male, Vinh Cuu, Ma Da, Bo Hao lotus lake, coll Tran A.D., 18 Apr 2009, TAD0911 (ZMHU); male, Vinh Cuu, Ma Da, Bo Hao lake, east side, near forest ranger station, coll Pham T.D., 15 Apr 2010, PTD1009 (ZMHU) Distribution Vietnam: Annam — Phuc Son (Lansbury, 1973, probably central Vietnam, see Remarks under Ranatra filiformis), Quang Binh, Quang Tri, Dong Nai Other countries: India, China, Thailand, Peninsular Malaysia, Singapore, Sarawak, Sumatra, and the Philippines (Lansbury, 1973; Chen et al., 2004; Polhemus and Polhemus, 2013) Cercotmetus compositus Montandon, 1903 Cercotmetus compositus Montandon, 1903: 109–110 Material examined VIETNAM: Thanh Hoa Prov.: male, Ben En N'Park, Nhu Xuan, Duc Binh, Khe Thong stream, coll Pham T.D., 28 Feb 2013, BE1303 (ZMHU) Dak Lak Prov.: female, Srepok River, next to HQ of Yok Don N′Park, 12°52.183′N 107°48.720′E, 211 m asl., coll Tran A.D & Tan H.H., 22, 24 Feb 2005, THH05–11 (ZRC); male, Yok Don National Park, Suoi Bo, near Guard post 6, 12°54.816′N 107°45.228′E, 239 m asl., coll Tran A.D & Tan H.H., 24 Feb 2005, THH05–14 (ZRC); Dong Nai Prov.: males, females, nymph, Nam Cat Tien, Dong Nai river, 11°26.158′N 107°25.738′E, 120 m asl., coll Tan H.H et al., May 2001, THH0114 (ZRC); male, Nam Cat Tien, A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 Ben Cu stream, 11°26.252′N 107°25.610′E, 135 m asl., coll Tan H.H et al., May 2001, THH0115 (ZRC); males, female, Nam Cat Tien, Muoi Que stream, 11°28.228′N 107°20.377′E, 130 m asl., coll Tan H.H et al., May 2001, THH0121 (ZRC); males, female, Nam Cat Tien, Sa Mach river, 11°20.071′N 107°10.755′E, 130 m asl., coll Tan H.H et al., May 2001, THH0123 (ZRC); male, females, nymphs, Nam Cat Tien, C 10 river, coll Tan H.H et al., 11 May 2001, THH0131 (ZRC); female, Nam Cat Tien, C river, coll Tan H.H et al., 11 May 2001, THH0132 (ZRC); female, Nam Cat Tien, Bau Chim, 11°23.975′N 107°22.653′E, 155 m asl., coll Tan H.H et al., 14 May 2001, THH0133 (ZRC) Distribution Vietnam: Annam — Phuc Son (Lansbury, 1973, probably central Vietnam, see Remarks under Ranatra filiformis), Thanh Hoa, Quang Tri, Dak Lak, Dong Nai Other countries: Thailand, Laos, Cambodia, Peninsular Malaysia, and Sumatra (Lansbury, 1973; Polhemus and Polhemus, 2013) Ranatra Fabricius, 1790 Ranatra nieseri sp.n Material examined Holotype: male, VIETNAM, Ninh Binh Prov., Gia Vien, Van Long Wetland Nature Reserve, 20°21.734′N 105°53.202′E, 16 m asl., coll Tran A.D., Jun 2003, TAD0347 (ZRC) Paratypes: males, female, same locality data as holotype (ZMHU, ZRC); males, VIETNAM, Ninh Binh Prov., Gia Vien, Van Long Wetland Nature Reserve, coll Hoang Q.K & Dinh V.K., 25 Aug 2002, VNNB0201 (ZRC) Description General colouration: light brown to brown, dorsum of body darker, legs paler (except for ventral side of fore coxa brown) 517 Structural characteristics: Measurements: Males: body length 22.0–24.5 (holotype: 24.5); length of siphon 16.0–19.0 (holotype: 19.0); width of head 2.43–2.58 (holotype: 2.58); width of eye 0.78–0.82 (holotype: 0.82); interocular width 0.78–0.88 (holotype 0.88); anterior width of pronotum 1.58; humeral width of pronotum 2.23; length of anterior lobe of pronotum along midline 3.89; length of posterior lobe along midline 2.02; fore leg: length of coxa 5.75, of femur 8.85; middle leg: length of femur 13.0, of tibia 15.0, of tarsi 2.10; hind leg: length of femur 13.20, of tibia 15.20, of tarsi 2.05 Female: body length 24.0; length of siphon 17.0; width of head 2.58; width of eye 0.88; interocular width 0.82; anterior width of pronotum 1.60; humeral width of pronotum 2.16; length of anterior lobe along midline 3.87; length of posterior lobe along midline 1.72; fore leg: length of coxa 5.80, of femur 8.90; middle leg: length of femur 12.5, of tibia 14.0, of tarsi 2.0; hind leg: length of femur 12.5, of tibia 14.5, of tarsi 2.1 Head (Figs 1, 6, 7): Vertex raised above eyes into low, conical tubercle; eyes reddish brown on dorsal part and red on ventral part; width of eyes subequal to interocular width; lora swollen but not raised above clypeus; clypeus surpassing lora, bearing short, stout, pale setae along longitudinal midline, similar setae also present apically on tylus; lateral sides of vertex and lora with some long, pale setae Antenna (Fig 8): second antennal segment with long, finger-like projection, clearly shorter in length than third antennal segment Thorax: Prothorax in lateral view slightly longer than fore coxa; anterior lobe about 1.9× as long as posterior lobe when measured along Figs 1–5 Ranatra species 1: R nieseri sp.n., anterior part of body showing head, prothorax, and fore leg, male; 2: R nieseri sp.n., metasternum, holotype; 3: R bilobata sp.n., left fore leg, male; 4: R bilobata sp.n., metasternum, holotype; 5: Ranatra sp., left fore leg, female (For interpretation of the references to colour in this figure, the reader is referred to the web version of this article.) 518 A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 Figs 6–16 Ranatra nieseri sp.n 6: head and prothorax, dorsal view; 7: head and prothorax, lateral view; 8: antenna; 9, 10: left fore leg and femoral teeth, outer view; 11, 12: left fore leg and femoral teeth, inner view; 13: metasternum; 14: paramere; 15: male phallotheca; 16: apex of abdomen of female, lateral view (6–14: male holotype; 15, 16: paratypes) longitudinal midline; anterior margin slightly raised when viewed laterally; ratio of humeral width / anterior width of male: 1.42 (holotype), of female: 1.35; anterior lobe of pronotum with weakly developed median groove; posterior lobe with humeri broadly rounded Scutellum with length ca 1.85–2.00× width (holotype: length 1.85× width), posterior section with a pair of roughly circular subapical depressions, one on each side of midline Prosternum with low median carina anteriorly, anterior margin slightly emarginated medially Mesosternum with anterior margin emarginated medially, posterior projection between mid-coxae narrow, truncate, with deep and narrow groove along midline Metasternum with weakly raised longitudinal carina on posterior two thirds, posterior margin slightly emarginated (Figs 2, 13) Space between middle coxae narrower than that between hind coxae Membrane just reaching posterior margin of tergite Legs: Mostly pale yellowish brown, fore coxa and femur with some irregular-spaced mottling Fore femur (Figs 1, 9–12) with two median teeth, larger tooth on outer face, smaller tooth situating immediately anterior to median tooth on inner face of femur; ratio of width of femur across larger tooth (including tuft of setae)/width of femur at basal half: 1.00–1.06 (holotype 1.06); ratio of width of femur across larger tooth/width at base of larger tooth at proximal side: males 1.58–1.65 (holotype 1.65), female 1.83; ratio of femur across larger tooth/width at base of larger tooth at distal side: males 2.00–2.11 (holotype 2.00), female 2.05 Middle femur subequal in length to hind femur; A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 hind femur in both sexes, when folded back along body nearly reaching but not reaching both tip of operculum and tip of tip of abdomen (excluding siphon) in male Middle and hind tibiae longer than respective femora; middle and hind femora both bearing sparsely distributed long, thin, pale hairs on posterior margins along their entire length; middle and hind tibiae both bearing dense fringe of long hairs on posterior margins along their entire length Abdomen: Operculum of male as long as connexivum, medially keeled, apex narrowly round Operculum of female (Fig 16) about as long as connexivum, just reaching base of respiratory siphon Male genitalia: Paramere (Fig 14) constricted at distal one third, with apical hook open and evenly curved, bearing a broad tooth-like elevation along inner margin before hook, apex expanded and truncate Phallotheca as in Fig 15 Remarks Ranatra nieseri sp.n belongs to the R biroi species group (sensu Lansbury, 1972) which is characterised by the respiratory siphon clearly shorter than body length, the fore femora bi-dentate, the middle and hind tibiae longer than respective femora, and eye width about subequal to interocular space Within this species group, this new species is most similar to Ranatra incisa Chen et al., 2004 (from Taiwan), and Ranatra recta Chen et al., 2004 (from Guangdong, China) in having similar general appearance of the paramere (with tooth-like elevation before apical hook), of the metasternum, and of the antennae It is, however, can be easily separated from the latter two by detailed structures of the paramere and metasternum In R nieseri sp.n., the paramere is distinctly constricted before the apical hook and the apex of the hook is broadened and truncate (Fig 14); in R incisa, the paramere is also constricted before the apical hook but the apex of the hook is rounded and not expanded (see Chen et al., 2004: Fig 35); in R recta, the paramere gradually tapers towards the apical hook, the dorsal margin of paramere is almost straight, the apex of the hook is rounded and not expanded (see Chen et al., 2004: Fig 36) The posterior margin of metasternum in R nieseri sp.n is emarginated (Figs 2, 13), while that of the latter two is straight, truncate or has a minute medial notch (see Chen et al., 2004: Figs 24, 25) In addition, in both R nieseri sp.n and R recta, the space between middle coxae is clearly narrower than the space between hind coxae (ca 0.7 times), while in R incisa, the space between middle and hind coxae is subequal Ranatra nieseri sp.n also shows some resemblance to R thai Lansbury, 1972, a very common species in Vietnam, but can be easily separated from the latter by the parameres, the structures of the metasternum, and the relative width of the space between middle and hind coxae In R nieseri sp.n., the paramere has a tooth-like elevation before the apical hook, the posterior margin of the metasternum is truncate and emarginated, the space between middle coxae is clearly narrower than that between hind coxae In R thai, the paramere is without subapical tooth-like elevation, the posterior margin of the metasternum is narrowly rounded, the space between middle and hind coxae is about equal In addition, the finger-like projection of the second antennal segment in R nieseri sp.n is more slender than that in R thai Etymology This species is dedicated to Dr Nico Nieser (National Museum for Natural History, Leiden) for his valuable contributions to the taxonomy of the Nepomorpha in Southeast Asia Distribution Vietnam: Ninh Binh Ranatra bilobata sp.n Material examined Holotype: male, VIETNAM, Dak Lak Prov., Yok Don National Park, Suoi Bo, near Guard post 6, 12°54.816′N 107°45.228′E, 239 m asl., coll Tran A.D & Tan H.H., 24 Feb 2005, THH05–14 (ZRC) Paratype: male, same locality data as holotype (ZMHU) Description General colouration: mostly brown or dark brown, venter and legs more yellowish, lacking distinct annulations but with irregularly-spaced, brown mottling on coxae and femora Measurements: Males: body length 35.0–36.5 (holotype: 35.0); length of siphon 40.5–41.0 (holotype: 40.5); width of head 3.28–3.42 (holotype: 3.28); width of eye 1.06–1.13 (holotype: 1.06); interocular 519 width 1.11–1.18 (holotype 1.11); anterior width of pronotum 2.55; humeral width of pronotum 3.59; length of anterior lobe of pronotum along midline 6.90; length of posterior lobe along midline 3.00; fore leg: length of coxa 6.20, of femur 10.20; middle leg: length of femur 12.0, of tibia 11.7, of tarsi 2.20; hind leg: length of femur 13.50, of tibia 14.50, of tarsi 2.60 Head (Figs 17, 18): Vertex slightly raised above eyes into small conical tubercle; eyes dark brown to black on dorsal, reddish brown on ventral; width of eyes subequal to interocular width; tylus longitudinally grooved; lora swollen, slightly raised above clypeus; clypeus not surpassing lora, bearing short, stout, pale setae along longitudinal midline, similar setae also present apically on tylus; lateral sides of vertex and lora with some long, pale setae Antenna (Fig 19): second antennal segment with long, finger-like projection, about equal to length of third segment Thorax: Prothorax with scattered erect yellowish setae Prothorax in lateral view distinctly longer than fore coxa; anterior lobe slightly over twice as long as posterior lobe when measured along longitudinal midline; anterior margin not raised when viewed laterally; ratio of humeral width/anterior width: 1.41 (male, holotype); anterior lobe of pronotum without median groove; posterior lobe with humeri broadly rounded Scutellum with length ca 1.63–1.67× width (holotype: length 1.67 × width), tapering posteriorly, posterior section with a pair of roughly semi-circular subapical depressions, one on each side of midline Prosternum rather flat, anterior half with weakly developed median carina, anterior margin almost straight Mesosternum broadly domed, with anterior margin emarginated medially, posterior projection between mid-coxae broad, truncate, flat, and without median groove Metasternum (Figs 4, 23): longitudinal carina weakly developed on posterior projection; posterior projection narrow, sublaterally with a pair of sickle-shaped tumescences thus forming two distinct lobes posteriorly; posterior margin emarginated Space between middle coxae slightly broader than that between hind coxae Membrane just slightly surpassing posterior margin of tergite Legs: Fore femur (Figs 3, 20–22) with a single median tooth, length of tooth (measured from dorsal margin of femur to apex of tooth and excluding acuminate apical setal tuft) less than maximum width of femur on basal half, distally with a small tooth-like elevation; ratio of width of femur across medial tooth (including tuft of setae)/width of femur at basal half: 1.11–1.15 (holotype 1.15); ratio of femur across medial tooth/width at base of tooth at distal side: 1.77–1.79 (holotype 1.79) Middle femur shorter than hind femur; hind femur when folded back along body not reaching posterior margin of sternite 6; middle and hind femora both bearing sparse distributed long, thin, pale hairs on posterior margins along their entire length; middle and hind tibiae both bearing dense fringe of long hairs on posterior margins along almost of their entire length Middle tibia subequal to middle femur; hind tibia clearly longer than hind femur Abdomen: Male operculum about as long as connexivum, slender, medially keeled, and with pointed apex Male genitalia: Paramere (Fig 24) slender, slightly tapering at distal third, bearing a strongly-developed and truncate tooth before apical hook; apical hook evenly curved towards narrowly rounded apex Phallotheca weakly sclerotized as in Fig 25 Female unknown Remarks Ranatra bilobata sp.n cannot be assigned to any species groups that were defined by Lansbury (1972) because it shows a mixture of character states of both the Ranatra gracilis and the Ranatra elongata species groups According to Lansbury (1972), the R gracilis species group is characterised by having the short respiratory siphon (about one third of the body length), the prominent tubercle on vertex, the emarginated posterior margin of metasternum, and the fore coxa being about as long as the fore femur and shorter than the prothorax, the short finger-like projection of the second antennal segment In contrast, the R elongata species group is characterised by having the long respiratory siphon (longer than the body length), the fore coxa distinctly 520 A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 Figs 17–25 Ranatra bilobata sp.n 17: head and prothorax, dorsal view; 18: head, lateral view; 19: antenna; 20: left fore leg, outer view; 21, 22: left fore leg and femoral teeth, inner view; 23: metasternum; 24: paramere; 25: male phallotheca (17–23: male holotype; 24, 25: male paratype) shorter than both the fore femur and the prothorax respectively (Lansbury, 1972) Ranatra bilobata sp.n has the emarginated posterior margin of metasternum and the conical tubercle (although small) on vertex, which are characteristics for the R gracilis species group In members of the R elongata species group, the posterior margin of metasternum is produced posteriorly and medially, but never emarginated and the vertex is without tubercle However, R bilobata sp.n does not fit the R gracilis species group because it has the long respiratory siphon is (clearly longer than body length), the shorter fore coxa (distinctly shorter than both the prothorax and the fore femur), the long finger-like projection of the second antennal segment The long respiratory siphon and the shorter fore coxa (clearly shorter than prothorax, and less than two thirds of fore femur) are characterised for members of the R elongata species group, but R bilobata sp.n cannot be placed in this species group because of the different structure metasternum as mentioned above Among its congeners, R bilobata sp.n is most similar to R sulawesii Nieser and Chen, 1991 from Sulawesi in having the long respiratory siphon, the long finger-like projection of the second antennal segment, the deeply emarginated posterior margin of metasternum, and the general form of the apex of paramere However, R bilobata sp.n differs from the latter by the following characteristics In R bilobata sp.n., a small tubercle is present on the vertex, the eye width is subequal to the interocular width, the posterior part of metasternum has a pair of sublateral sickle-shaped tumescences, the space between middle coxae is slightly broader (ca 1.1 times) than that between hind coxae, the paramere has its dorsal margin slightly arched at basal part and has a long distal tooth before the apical hook In Ranatra sulawesii, the tubercle on the vertex is distinct, the eye is slightly wider than the interocular width, the posterior part of metasternum is without sublateral tumescences, the space between middle coxae is subequal A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 to that between hind coxae, the paramere has its dorsal margin almost straight and has a shorter and more curve distal tooth before the apical hook In the subspecies R sulawesii sebui Nieser and Chen, 1996 from Lake Sebu (Mindanao), the tubercle on vertex is very small, indicating that this character is variable Ranatra bilobata sp.n is also similar to Ranatra sterea Chen et al., 2004 from Yunnan, China in having the deeply emarginated posterior margin of metasternum and the long finger-like projection of the second antennal segment Chen et al (2004) noted the uncertainty about the placement of R sterea to an appropriate species group, because it also has similarities to both the R gracilis and the R elongata species group (see Chen et al., 2004: 99) Unfortunately, in R sterea, only female specimens are known, while in R bilobata sp.n., only male specimens are known Thus the comparison of the male genitalia of the two species is not possible However, some significant differences show that they are separate species In R sterea, the respiratory siphon is slightly shorter than the body length; the vertex is not raised above the eyes and has no tubercle; the prothorax is longer (ca 1.3 times) than the fore coxa and shorter (ca 0.76 times) than the fore femur; the metasternum has a pair of sublateral grooves In R bilobata sp.n., the respiratory siphon is clearly longer than the body length; the vertex is slightly raised above the eyes and has a small but clearly visible tubercle; the prothorax is distinctly longer (ca 1.6 times) than the fore coxa, and is only about as long as the fore femur; the metasternum has a pair of sublateral tumescences Nieser and Chen (1991) assigned R sulawesii to the R gracilis species group, mostly based on the deeply emarginated posterior margin of metasternum, and they also noted the key differences between R sulawesii and other members of the R gracilis species group, including the long respiratory siphon and the long finger-like projection of the second antennal segment In our opinion, R sulawesii therefore should not be assigned to the R gracilis species group Ranatra bilobata sp.n., R sulawesii (and its subspecies R sulawesii sebui), and R sterea may form a distinct species group However, until an extensive taxonomic study of the genus Ranatra is carried out, it is still premature to assign the taxa above to any species group Etymology The word bilobata refers to the distinct two lobes of posterior projection of the metasternum Distribution Vietnam: Dak Lak Ranatra chinensis Mayr, 1865 Ranatra chinensis Mayr, 1865: 446 Material examined VIETNAM: Lao Cai Prov.: male, females, nymphs, Sa Pa, Nui Xe, water pools near Suoi Vang, 22°20.953′N 103°46.234′E, 1900 m asl., coll Tran A.D., Jun 2003, TAD0346 (ZRC); female, Sa Pa, Nui Xe, Tram Ton area, Vang stream, 22°20.908′N 103°46.193′E, 1900 m asl., coll Tran A.D et al., 25 Oct 2013, TAD1356 (ZMHU) Distribution Vietnam: Lao Cai, Hoa Binh Other countries: Russia (Far East), Korea, Japan, China, Myanmar, and India (Lansbury, 1972; Polhemus, 1995; Chen et al., 2004) Ranatra falloui Montandon, 1907 Ranatra falloui Montandon, 1907: 54 Ranatra maculipes Matsumura, 1913: 94 (synonymised by Lansbury, 1972: 314) Distribution Vietnam: Hoa Binh (Lansbury, 1972) Other countries: China (Fukien), Taiwan, and Thailand (Koh Chang Is in the Gulf of Siam) (Lansbury, 1972; Chen et al., 2004) Ranatra filiformis Fabricius, 1790 Ranatra filiformis Fabricius, 1790: 228 Remarks The only record from Vietnam of this species was provided by Lansbury (1972) based on sample collected from the locality “Annam, Phuc Son” Annam was the old name of central part of Vietnam, which was used during the French colonisation period However, there are a few localities named “Phuc Son” in northern and central Vietnam Thus, it is not possible to determine the exact position (e.g., province) of the locality above 521 Distribution Vietnam: Annam — Phuc Son (Lansbury, 1972, probably central Vietnam, see Remarks above) Other countries: India, Sri Lanka, and Nepal (Lansbury, 1972) Ranatra parmata Mayr, 1865 Ranatra parmata Mayr, 1865: 446 Material examined VIETNAM: Thanh Hoa Prov.: males, Ben En N'Park, Nhu Xuan, La Rong stream, coll Pham T.D., 03 Aug 2012, BE1204 (ZMHU); male, Ben En N'Park, Nhu Xuan, Son Binh, Khe Cay Khe stream, site 1, coll Pham T.D., 01 Mar 2013, BE1304 (ZMHU); males, nymphs, Ben En N'Park, Nhu Xuan, Son Binh, Khe Cay Khe stream, site 2, 300 m down-stream from site 1, coll Pham T.D., 01 Mar 2013, BE1305 (ZMHU); female, Ben En N'Park, Nhu Xuan, Son Binh, Khe Cay Khe stream, site 3, 800 m down-stream from site 1, coll Pham T.D., 01 Mar 2013, BE1306 (ZMHU); males, females, nymphs, Ben En N'Park, Nhu Xuan, Xuan Quy, Song Chang ranger station, Khe Khoanh stream, coll Pham T.D., 11 Mar 2013, BE1310 (ZMHU) Dong Nai Prov.: males, females, Nam Cat Tien, Lan stream A, 11°21.018′N 107°11.645′E, 90 m asl., coll Tan H.H et al., 10 May 2001, THH0129 (ZRC); female, Vinh Cuu, Ma Da, stream near former Coi Xay base (tributary of Ma Da stream), coll Tran A.D., 01 Nov 2009, TAD0920 (ZMHU); female, Vinh Cuu, Ma Da, 2nd no-name stream on the way to former “D-base” headquarter, coll Tran A.D., 01 Nov 2009, TAD0922 (ZMHU) Kien Giang Prov., Phu Quoc Island: female, Da Ban stream & waterfall, 10°14.690′N 104°01.954′E, 55 m asl., coll Tran A.D & D Yeo, 29 Nov 2010, TAD1020 (ZMHU); female, Tranh stream (middle section & waterfall), 10°10.770′N 104°0.852′E, 35 m asl., coll Tran A.D., 30 Nov 2010, TAD1022 (ZMHU) CHINA: Hainan Prov.: male, Baoting, Lingshui river basin; stream along road before Bacun, coll I-S Chen et al., 10 Sep 2005, THH05–71 (ZRC) Distribution Vietnam (first records): Thanh Hoa, Dong Nai, Phu Quoc Other countries: N Thailand, Laos, Java, Sumatra (Lansbury, 1972), and China — Hainan island (first record for China) Ranatra thai Lansbury, 1972 Ranatra longipes thai Lansbury, 1972: 334; Tran and Polhemus, 2012: 102, 104 (elevated to species ranking) Material examined VIETNAM: Hanoi: females, nymphs, Thanh Xuan district, Thanh Huong lake, coll P.T Mai, 20 Apr 2010 (ZMHU) Thanh Hoa Prov.: female, Ben En N'Park, Nhu Xuan, Duc Binh, Khe Thong stream, coll Pham T.D., 28 Feb 2013, BE1303 (ZMHU) Dak Lak Prov.: female, Yok Don National Park, Dak Min lake, 12°55.686′N 107°48.566′E, 200 m asl., coll Tran A.D & Tan H.H., 22 Feb 2005, THH05–09 (ZRC); male, Yok Don National Park, Suoi Bo, near Guard post 6, 12°54.816′N 107°45.228′E, 239 m asl., coll Tran A.D & Tan H.H., 24 Feb 2005, THH05–14 (ZRC) Dong Nai Prov.: male, Nam Cat Tien, Bau Sau, 11°27.531′N 107°20.702′E, 145 m asl., coll Tan H.H et al., 6–7 May 2001, THH0119 (ZRC); male, Nam Cat Tien, Sa Mach river, 11°20.071′N 107°10.755′E, 130 m asl., coll Tan H.H et al., May 2001, THH0123 (ZRC); males, Nam Cat Tien, Kra river, 11°21.462′N 107°12.035′E, 120 m asl., coll Tan H.H et al., 10 May 2001, THH0127 (ZRC); male, female, Nam Cat Tien, Bau Chim, 11°23.975′N 107°22.653′E, 155 m asl., coll Tan H.H et al., 14 May 2001, THH0133 (ZRC); female, Vinh Cuu, Ma Da, Bo Hao lake, east side, near forest ranger station, coll Tran A.D., 10 Apr 2009, TAD0906 (ZMHU); male, females, Vinh Cuu, Ma Da, stream near former Coi Xay base (tributary of Ma Da stream), coll Tran A.D., 01 Nov 2009, TAD0920 (ZMHU); males, female, Vinh Cuu, Nua stream (tributary of Ma Da stream), coll Pham T.D., 14 Apr 2010, PTD1008 (ZMHU); female, Vinh Cuu, Ma Da, Suoi Lop (Lop stream), coll Pham T.D., 16 Apr 2010, PTD1013 (ZMHU) Ba Ria — Vung Tau Prov., Con Dao island: females, Dam Trau area, mangroves, area with sandy bottom, 08°43.798′N 106°37.203′E, coll Tran A.D et al., 13 Apr 2010, TAD1008 (ZMHU) Kien Giang Prov., Phu Quoc Island: males, females, Da Ban stream & waterfall, 10°14.690′N 104°01.954′E, 55 m asl., coll Tran A.D & D Yeo, 29 Nov 2010, TAD1020 (ZMHU); male, Tranh stream (at lower section), 10°10.727′N 104°00.802′E, 32 m asl., coll Tran A.D et al., 30 522 A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 Nov 2010, TAD1021 (ZMHU); males, females, Tram stream & swamp near mangroves, coll Tran A.D., 01 Dec 2010, TAD1023 (ZMHU) Distribution Vietnam: Cao Bang, Hanoi, Thanh Hoa, Quang Tri, Quang Ngai, Phu Yen, Binh Dinh, Gia Lai, Dak Lak, Dong Nai, Con Dao, Phu Quoc (including records by Tran and Polhemus, 2012) Other countries: Thailand, Peninsular Malaysia (Lansbury, 1972; Tran and Polhemus, 2012) Ranatra varipes Stål, 1861 Ranatra varipes Stål, 1861: 203 Material examined VIETNAM: Ninh Binh Prov.: male, female, Gia Vien, Van Long Wetland Nature Reserve, 20°21.734′N 105°53.202′ E, 16 m asl., coll Tran A.D., Jun 2003, TAD0347 (ZRC) Lam Dong Prov.: males, female, nymph, Bao Loc, Nam Phuong Lake, 11°33.887′N 107°48.818′E, 815 m asl., coll Tran A.D., 20 May 2003, TAD0328 (ZRC) Dong Nai Prov.: male, female, nymph, Nam Cat Tien, Bau Sau, 11°27.531′N 107°20.702′E, 145 m asl., coll Tan H.H et al., 6–7 May 2001, THH0119 (ZRC); female, female, Nam Cat Tien, Bau Chim, 11°23.975′N 107°22.653′E, 155 m asl., coll Tan H.H et al., 14 May 2001, THH0133 (ZRC); male, Bien Hoa City, Bien Hung Lake, 10°56.999′N 106°49.554′E, 22 m asl., coll Tran A.D., May 2003, TAD0314 (ZRC); males, Cat Tien N'Park, Bau Sau (Crocodile lake), coll Tran A.D., Nov 2009, TAD0929 (ZMHU); male, Vinh Cuu, Ma Da, Bo Hao lake, east side, near forest ranger station, coll Tran A.D., 10 Apr 2009, TAD0906 (ZMHU) Ba Ria — Vung Tau Prov., Con Dao Island: female, Dam Trau area, mangroves, area with sandy bottom, 08°43.798′N 106°37.203′E, coll Tran A.D et al., 13 Apr 2010, TAD1008 (ZMHU) CAMBODIA: males, 20 km SW of Phnom Penh, coll H.H Tan & H.H Ng, 22 May 1999, THH9922 (ZRC); male, swampy margin of Great Lake of Tongle Sap, nr Siem Reap, coll T.R Roberts, Jan 1994, RTR199401 (ZRC) THAILAND: female, 82 km N Khon Kaen to Chai Ya Pun, coll Y.X Cai & Y.Y Goh, 20 Jun 1998, CYX9838 (ZRC); male, females, S Thailand, Narathiwat Prov., Phikuntha, Mae Nam Wan Nara, coll H.H Tan et al., 24 Oct 1998, THH9888/LHK404 (ZRC); males, females, nymph, N Thailand, 98 km from Buri Ram to Ubon Rachathani, coll Y.Y Goh, 16 Jun 1998, GYY92 (ZRC); female, Nakon Rachasima, fr Korat to Bangkok, coll H.H Tan, 16 Jan 1997, THH9715 (ZRC); female, nymph, Chantaburi Prov., swamp n of Chantaburi, coll M Kottelat et al., Dec 1993, CMK93–117 (ZRC); male, female, Chantaburi Prov., Nam Tok Phliu, waterfall, coll H.H Tan, 14 Jan 1997, THH9705 (ZRC); male, female, nymph, Trat Prov., coll H.H Tan, 15 Jan 1997, THH9709 (ZRC) MYANMAR: males, females, Shan State, Inle Lake, at Mine Thauk Canal, coll H.H Tan, 26 Feb 1999, THH9909 (ZRC) Distribution Vietnam: Annam — Phuc Son (Lansbury, 1972, probably central Vietnam, see Remarks under Ranatra filiformis), Ninh Binh, Lam Dong, Dong Nai, Con Dao Other countries: India, Sri Lanka, Thailand, Laos, Peninsular Malaysia, Singapore, Java, and Sumatra (Lansbury, 1972; Polhemus and Polhemus, 2013) Ranatra sp Material examined VIETNAM: Dong Nai Prov.: female, Nam Cat Tien, Muoi Que stream, 11°28.228′N 107°20.377′E, 130 m asl., coll Tan H.H et al., May 2001, THH0121 (ZRC) Remarks This female specimen apparently belongs to an undescribed species This specimen has the body length at 39 mm, length of siphon at 32 mm, and the operculum slightly shorter than connexivum It has the fore femur with a prominent larger tooth on the external side of the femur and smaller tooth on the inner side (Figs 5, 26–28), somewhat similar to the fore femora of Ranatra malayana Lundblad, 1933 and R katsara Nieser, 1997, but the larger tooth is much larger than that of the latter two However, its status can be confirmed only when associated male specimens are collected Extralimital record Ranatra libera Zettel, 1999 Figs 26–28 Ranatra sp from Cat Tien, Dong Nai Prov., female specimen 26: left fore leg, outer view; 27, 28: left fore leg and femoral teeth, inner view Material examined THAILAND: males, Mae Sot, Mae Nam Moi, coll H.H Tan & H.H Ng, 26 May 1999, THH9929 (ZRC) Remarks Previously, this species was only known from its type locality in Bago (Myanmar) When studying the collection in ZRC, we found the specimens listed above They represent the first record of R libera from Thailand Distribution Myanmar (Zettel, 1999), Thailand (first record) Acknowledgements We sincerely thank Prof Nguyen Xuan Quynh, Mr Nguyen Van Hieu, and Mr Nguyen Thanh Son (Vietnam National University, Hanoi) for assistance and help during fieldwork The first author would like to express our sincere thanks to Prof Peter K.L Ng, Ms Lua Hui Kheng, Dr Hwang Wei Song, and Mrs Yang Chang Man (all Lee Kong Chian Natural History Museum, National University of Singapore) for providing generous support to the first author during his visits to the museum for comparative study in the collection held there Thanks are also due to Dr Tan Heok Hui and Dr Yuchen Ang (National University of Singapore) providing instruction to operate the Visionary Digital photography system based in the museum This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 106.15-2012.69 References Chen, P.P., Nieser, N., Ho, J., 2004 Review of Chinese Ranatrinae (Hemiptera: Nepidae), with descriptions of four new species of Ranatra Fabricius Tijdschrift voor Entomologie 147, 81–102 Chen, P.P., Nieser, N., Zettel, H., 2005 The aquatic and semi-aquatic bugs (Heteroptera: Nepomorpha & Gerromorpha) of Malesia Fauna Malesiana Handbooks Leiden and Boston, Brill (546 pp) Keffer, S.L., Polhemus, J.T., 1999 A new species of Cercotmetus Amyot & Serville (Heteroptera: Nepidae) from Laos J N Y Entomol Soc 107 (1), 28–30 A.D Tran, V.V Nguyen / Journal of Asia-Pacific Entomology 19 (2016) 515–523 Lansbury, I., 1972 A review of the Oriental species of Ranatra Fabricius (HemipteraHeteroptera: Nepidae) Transactions of the Royal Entomological Society of London 124, 287–341 Lansbury, I., 1973 A review of the genus Cercotmetus Amyot & Serville, 1843 (HemipteraHeteroptera: Nepidae) Tijdschrift voor Entomologie 116, 84–106 Lundblad, O.M., 1933 Zur Kenntniss der aquatilen und semiaquatilen Hemipteren von Sumatra Java und Bali Acrchiv für Hydrobiologie Supplementum 12 (1–195), 263–489 Nieser, N., 1996 Two new species of Ranatra Fabricius from Southeast Asia (Insecta: Heteroptera: Nepidae) Ann Naturhist Mus Wien 98 (B), 347–351 Nieser, N., 1997 A new species of Ranatra from Thailand (Insecta: Heteroptera: Nepidae) Ann Naturhist Mus Wien 99B, 79–82 Nieser, N., Chen, P.P., 1991 Naucoridae, Nepidae and Notonectidae, mainly from Sulawesi and Pulau Buton (Indonesia), I Tijdschrift voor Entomologie 134, 47–67 Nieser, N., Chen, P.P., 1996 Six new taxa of Nepomorpha from Sulawesi and Mindanao Notes on Malesian aquatic and semiaquatic bugs (Heteroptera), VI Tijdschrift voor Entomologie 139 (2), 161–174 523 Nieser, N., Polhemus, J.T., 1998 Introduction to the Nepidae of Thailand Amemboa 2, 19–23 Polhemus, J.T., 1995 Family Nepidae — In: Aukema, B & Rieger, C (eds.) Catalogue of the Heteroptera of the Palaearctic Region Enicocephalomorpha, Dipsocoromorpha, Nepomorpha, Gerromorpha & Leptopodomorpha — The Netherlands Entomological Society, Amsterdam: 14–18 Polhemus, J.T., Polhemus, D.A., 2008 Global diversity of true bugs (Heteroptera: Insecta) in freshwater Hydrobiologia 595, 379–391 Polhemus, D.A., Polhemus, J.T., 2013 Guide to the aquatic Heteroptera of Singapore and Peninsular Malaysia X Infraorder Nepomorpha – Families Belostomatidae and Nepidae Raffles Bull Zool 61 (1), 25–45 Tran, A.D., Polhemus, D.A., 2012 Notes on Southeast Asian Ranatra (Heteroptera: Nepidae), with description of a new species from Singapore and neighbouring Indonesian islands Raffles Bull Zool 60 (1), 101–107 Zettel, H., 1999 Ranatra libera sp.n (Heteroptera: Nepidae) from Burma Linzer biologische Beiträge 31 (1), 427–430  ... of the paramere (with tooth-like elevation before apical hook), of the metasternum, and of the antennae It is, however, can be easily separated from the latter two by detailed structures of the. .. contributions to the taxonomy of the Nepomorpha in Southeast Asia Distribution Vietnam: Ninh Binh Ranatra bilobata sp.n Material examined Holotype: male, VIETNAM, Dak Lak Prov., Yok Don National... states of both the Ranatra gracilis and the Ranatra elongata species groups According to Lansbury (1972), the R gracilis species group is characterised by having the short respiratory siphon