The genus Metrocoris Mayr, 1865 (Gerromorpha: Gerridae) in Vietnam, with descriptions of five new species Author A. D., Tran Author Polhemus, D. A. text Raffles Bulletin of Zoology 2017 2017-05-24 65 109 149 journal article 6572 10.5281/zenodo.4502634 fde5f083-514d-400b-b886-e792390afd86 2345-7600 4502634 E9197A2F-EE46-4E5E-93C5-37E4CEC1A240 Metrocoris stranguloides Chen & Nieser, 1993 ( Figs. 3, 4 , 32 , 44–46 ) Metrocoris stranguloides Chen & Nieser, 1993: 16–18 , Figs, 29, 38, 44–45 ( type locality: Hainan Island, China ); Zettel & Chen, 1996: 152 , 176 (faunistic notes). Material examined. VIETNAM : Quang Binh Prov. : 1 female (apt) , 1 male (mpt), Phong Nha , upstream of Thac Xoi waterfall, coll. Tran A.D. , 15 July 2004 , DY0407 ( ZRC ) . Da Nang Prov. : 6 males , 3 females (apt) , 1 male , 3 females (mpt), Ba Na - Nui Chua , Suoi Cat Lon , 700 m asl , coll. Tran A.D. & Tan H.H. , 28 February 2005 , THH05-19 ( ZRC ) ; 1 male , 1 female (apt), Ba Na - Nui Chua , rocky cascade along road to summit, coll. Tran A.D. & Tan H.H. , 28 February 2005 , THH05-20 ( ZRC ) ; 1 male , 1 female (mpt), Ba Na-Nui Chua , Suoi Nai - Thac Cau Vong , coll. Tran A.D. & Tan H.H. , 01 March 2005 , THH05-23 ( ZRC ) ; 2 males , 1 female (apt), 3 males (mpt), Ba Na - Nui Chua foothills, Suoi Lanh , coll. Tran A.D. & Tan H.H. , 01 March 2005 , THH05-25 ( ZMHU ) . Quang Ngai Prov. : 18 males , 27 females (apt) , 4 males , 1 female (mpt), rocky stream crossing road on E. side of Via Lac Pass , 109 km NE. of Kontum on Hwy. 24, 305 m asl , 14°46′27″N , 108°32′18″E , water temp. 26.5°C, 17 March 2001 , CL 4297, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) . Kon Tum Prov. : 2 males , 5 females (apt.), stream 77 km NE. of Kontum on Hwy. 24, 1195 m asl, 14°38′23″N , 108°23′38″E , water temp. 19°C, 6 March 2001 , CL 4283, coll. J.T. Polhemus and P. Nguyen ( USNM ) ; 3 males , 6 females (apt), 3 females (mpt), small stream 97 km NE. of Kontum on Hwy. 24, 1065 m asl, 14°42′28″N , 108°27′46″E , water temp. 21°C, 20 March 2001 , CL 4303, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) ; 4 males , 12 females (apt), 1 male , 2 females (mpt), stream 96 km NE. of Kontum on Hwy. 24, 1020 m asl, 14°41′58″N , 108°27′33″E , water temp. 22°C, 20 March 2001 , CL 4304, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) . Gia Lai Prov. : 12 males , 11 females (apt) , 2 males , 3 females (mpt), 40 km NW. An Khe , Buon Luoi , 14°10′N , 108°30′E , 620–750 m asl , coll. Pacholátko & Dembicky , 28 March–12 April 1995 ( NHMW , 5 males , 5 females in ZRC ) ; 12 males , 16 females (apt), 1 female (mpt), Tral Stream , 60 km N. of An Khe , 700 m asl , 14°20′28″N , 108°34′49″E , water temp. 23.5°C, 22 March 2001 , CL 4309, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) ; 4 males , 7 females (apt), 1 male , 1 female (mpt), small hill stream in primary forest, 68 km N. of An Khe , 840 m asl , 14°20′52″N , 108°32′57″E , water temp. 21°C, 22 March 2001 , CL 4311, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) ; 1 female , 1 male (apt), Nuoc Stream , 47 km N. of An Khe , 580 m asl , 14°14′17″N , 108°36′17″E , water temp. 24°C, 23 March 2001 , CL 4312, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) . Binh Dinh Prov. : 9 males , 4 females (apt), stream in boulders on E. side of An Khe Pass , 16 km E. of An Khe on Hwy. 19, 365 m asl , 13°57′43″N , 108°45′48″E , water temp. 19.5°C, 21 March 2001 , CL 4307, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) . Phu Yen Prov. : 1 male , 5 females (apt), seeps and streamlets on S. side of Ca Pass , 33 km S. of Tuy Hoa on Hwy. 1, 105 m asl , 12°51′47″N , 109°23′53″E , water temp. 25°C, 25 March 2001 , CL 4315, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( USNM , BPBM ) . Lam Dong Prov. : 19 males , 10 females (apt), Suoi Vang , 18 km NW. of Da Lat, coll. Vásárhelyi , 17 October 1988 , No. 308 ( MTMB , NHMW ) ; 69 males , 115 females (apt), 7 males , 13 females (mpt), 12 km N Dalat-LangBian, coll. P. Pacholátko & L. Dembicky , 28–30 April 1994 ( NHMW , ZRC ) ; 5 males , 3 females (apt), 2 females (mpt), 12 km N Dalat-Langbian , 12°03′N 108°27′E , 1680–1750 m asl , coll. Pacholátko & Dembicky , 17–21 April 1995 ( NHMW , 4 males , 4 females in ZRC ) ; 1 male , 3 females (apt), 1 female (mpt), 16 km N Da Lat-Ankreot , 12°05′N , 108°24′E , 1400 m asl , coll. Pacholátko & Dembicky , 15 April 1995 ( NHMW ) ; 5 females (apt), Duc Me , 15 km S. of Bao Loc , 700 m asl , coll. Vásárhelyi , 23 October 1988 , No. 371 ( MTMB ) ; 1 male , 1 female (apt), Suoi Baco , 12 km S. of Bao Loc , 800 m asl , coll. Vásárhelyi , 25 October 1988 , No. 386 ( MTMB ) ; 1 male , 1 female (apt), 1 male , 4 females (mpt), Da Lat, a stream running into Dankia lake , coll. Tran A.D. , 21 May 2003 , TAD0330 ( ZRC ) ; 4 males , 3 females (apt), 1 female (mpt), Da Lat , Datanla waterfall, coll. Tran A.D. , 22 May 2003 , TAD0333a ( ZRC ) ; 3 males , 3 females (apt), 1 female (mpt), Dambri Waterfall, N. of Bao Lac , 850 m asl , 11°38′14″N , 107°44′54″E , water temp. 24°C, 7 May 1998 , CL 3075, coll. J.T. Polhemus & P. Nguyen ( USNM , BPBM ) ; 7 males , 12 females (apt), small steeply dropping stream at Mother Mary Shrine , along Hwy. 20 on S. side of Bao Lac Pass , 18 km W. of Bao Lac , 800 m asl , 11°27′09″N , 107°43′21″E , water temp. 24.5°C, 7 May 1998 , CL 3076, coll. J.T. Polhemus & P. Nguyen ( DAPC ) ; 3 males , 3 females (apt), stream below Suoi Vàng hydro project (= Gold Stream ), 16 km N. of Dalat , 1430 m asl , 11°59′26″N , 108°22′06″E , water temp. 24.5°C, 9 May 1998 , CL 3078, coll. J.T. Polhemus & P. Nguyen ( DAPC ) ; 10 males , 9 females (apt), 1 female (mpt), small tribs. to stream below Suoi Vàng hydro project (= Gold Stream ), 16 km N. of Dalat , 1430 m asl , 11°59′26″N , 108°22′06″E , water temp. 19.5°C, 9 May 1998 , CL 3079, coll. J.T. Polhemus & P. Nguyen ( DAPC ) ; 1 male (apt), spring fed trib. to stream below Suoi Vàng hydro project (= Gold Stream ), 16 km N. of Dalat , 1430 m asl , 11°59′26″N , 108°22′06″E , 9 May 1998 , CL 3080, coll. J.T. Polhemus & P. Nguyen ( DAPC ) ; 6 males , 8 females (apt), 2 males , 1 female (mpt), Prenn Falls , 13 km S. of Dalat on Hwy. 20, 1160 m asl, 11°52′43″N , 108°28′19″E , water temp. 25.5°C, 10 May 1998 , CL 3083, coll. J.T. Polhemus & P. Nguyen ( DAPC ) ; 3 males , 1 female (apt), 4 males , 5 females (mpt), small rocky stream at Lang Biang Mtn. , 12 km N. of Dalat , 1465 m asl , 12°01′12″N , 108°25′27″E , water temp. 20°C, 11 May 1998 , CL 3084, coll. J.T. Polhemus & P. Nguyen ( USNM , BPBM ) ; 35 males , 27 females (apt), 3 males , 7 females (mpt), tributary stream to main river at Suoi Vang , 1430 m asl , 11°59′26″N , 108°22′06″E , water temp. 21°C, 11 and 18 May 1998 , CL 3085, coll. J.T. Polhemus & P. Nguyen ( USNM , BPBM ) ; 3 females (apt), 2 males (mpt), stream and cascade 6 km S. of Dalat on Hwy. 20, 1390 m asl, 11°54′10″N , 108°26′46″E , 20 May 1998 , CL 3095, coll. J.T. Polhemus & P. Nguyen ( DAPC ) ; 15 males , 24 females (apt), 4 males , 5 females (mpt), stream in pine forest 13 km N. of Dalat on Suoi Vang road, 1495 m asl , 11°59′26″N , 108°23′19″E , water temp. 21.5°C, 28 March 2001 , CL 4317, D.A. Polhemus , J.T. Polhemus and P. Nguyen ( USNM , BPBM ) . Ninh Thuan Prov. : 1 male (apt), Nui Chua N’Park , suoi Lo O , coll. Quang N.V. , 26 June 2004 , NC-03 ( ZRC ) ; 19 males , 40 females (apt), 2 males (mpt), first small stream on E. side of Belleview Pass ( Ngoan Muc Pass ), 66 km NW. of Phan Rang , pools and cascades, 915 m asl , 11°50′25″N , 108°39′21″E , water temp. 24°C, 12 May 1998 and 26 March 2001 , CL 3087, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( DAPC , USNM , BPBM ) ; 3 males , 1 female (apt), 1 male (mpt), spring fed stream in granite at shrine on E. side of Belleview Pass ( Ngoan Muc Pass ), 58 km NW. of Phan Rang , 700 m asl , 11°50′41″N , 108°39′57″E , water temp. 724°C, 12 May 1998 , CL 3089, coll. D.A. Polhemus , J.T. Polhemus & P. Nguyen ( DAPC ) . Figs. 3–17. Dorsal colour patterns of Metrocoris species, all apterous morph. 3, 4: M. stranguloides , specimens from Vietnam, Gia Lai Prov., 60 km N. of An Khe (CL 4309). 5, 6: M. bilobatoides , specimens from Vietnam, Lao Cai Prov., 12 km NW. of Sa Pa (CL 4404). 7, 8: M. johnpolhemi , new species , specimens from Vietnam, Lai Chau Prov.; male from 12 km N. of Lai Chau (CL 4410), female from Nam Ceung stream (CL 4409). 9: M. vietnamensis , paratype, from Vietnam, Da Nang Prov., Ba Na - Nui Chua (TAD0334) (9 reproduced and modified from Tran & Zettel, 2005 ). 10, 11: M. quynhi , specimens from Vietnam, Lao Cai Prov., 18 km NW. of Sa Pa (CL 4400). 12, 13: M. obscurus , specimens from Vietnam, Lao Cai Prov., 4 km NE. of Sa Pa (CL 4407). 14, 15: M. acutus , specimens from Vietnam, Hai Hung Prov., 22 km N. of Chi Linh (CL 4375). 16, 17: M. nigrofascioides , specimens from Vietnam, Binh Dinh Prov., An Khe Pass (CL 4291). CHINA : Hainan Prov. : 1 female (apt), Hainan (193), 30 km E. Maoyang , 600 m asl , Wuzhi Shan Resort , coll. Jäch , 17–18 January 1996 ( NHMW ) ; 1 female (mpt), Wuzhishan , hill stream near Fanxiang , before Shuiman , coll. I-S. Chen et al., 9 September 2005 , THH05-67 ( ZRC ) ; 13 males , 7 females (apt), 1 female (mpt), Qiongzhong , Baihua waterfall, near Qiongzhong town , coll. I-S. Chen et al., 11 September 2005 , THH05-73 ( ZRC ) ; 1 male (apt), Qiongzhong , Linmushan forest park, ca. 15 km into track from road, coll. I-S. Chen et al., 11 September 2005 , THH05-77 ( ZRC ) ; 1 male , 4 females (apt), 1 female (mpt), Baisha , river along road near Yuanmen , to Wuzhishan , coll. I-S. Chen et al., 12 September 2005 , THH05-82 ( ZRC ) . LAOS : Luang Nam Tha Prov. : 3 males , 1 female (apt) , 2 females (mpt), 20 km SE. Muang Sing , 950 m asl , coll. Schillhammer (25), 12 June 1996 ( NHMW ) . Diagnosis. Male: fore femur strongly incrassate with two sub-apical teeth and a median tooth ( Figs. 44, 45 ). Male genitalia large: pygophore sub-ovate (ventral view), slightly raised posteriorly (lateral view); proctiger elongate; paramere long and slender, curved at distal part, but not twisted ( Fig. 32 ); endosoma as in Chen & Nieser (1993 : Figs. 44, 45 ). Female: sternum 7 with broad median lobe, posterior margin of median lobe almost straight ( Fig. 46 ). Figs. 18–31. Dorsal colour patterns of Metrocoris species. 18, 19: M. inthanon , specimens from Vietnam, Nghe An Prov., Pu Mat Nature Reserve (CL 4385). 20, 21: M. sicilis , new species , paratypes, from Vietnam, Hanoi, Ba Vi N’Park (CL 4393). 22, 23: M. triangulatus , specimens from Vietnam, Kontum Prov., 60 km NW. of Kontum (CL 4280). 24, 25: M. nigriventris , new species , paratypes, from Vietnam, Lai Chau Prov., 12 km N. of Lai Chau (CL 4410). 26, 27: M. monticola , new species , paratypes, from Vietnam, Lao Cai Prov., Sa Pa, Sin Chai (TAD1363). 28, 29: M. sapa , new species , paratypes, from Vietnam, Lao Cai Prov., Sa Pa, Nui Xe (TAD0416). 30, 31: M. tenuicornis , specimens from Vietnam, Gia Lai Prov., 60 km N. of An Khe (CL 4309). Size: apterous males: length 5.5–6.5, width 2.81–3.23, macropterous males: length 7.2–8.3, width 2.71–3.14; apterous females: length 4.8–5.4, width 2.57–3.05, macropterous females: length 6.2–7.4, width 2.67–3.20. Remarks. Metrocoris stranguloides is the only species of the M. strangulator group known from Vietnam . As defined by Chen & Nieser (1993) , the following are characteristics of this group: strongly incrassate fore femur (males), with two sub-apical teeth and a median tooth; large male genitalia with prominent paramere; sternum 7 of female with broad medial lobe. This group contains five species: M. stragulator Breddin (from Java and Sumatra), M. armatus Chen & Nieser (from Thailand ), M. malayensis Chen & Nieser (from Thailand and Peninsular Malaysia ), M. nieseri Chen & Zettel (from Thailand ), and M. stranguloides Chen & Nieser (initially described from Hainan Island and S. Vietnam ). Metrocoris stranguloides can be easily distinguished from the other four species in this group by having a long and slender paramere, simply curved on the distal part but not twisted ( Chen & Nieser, 1993 ). Females of this species are also rather different from those of the other four taxa in having a straight hind margin of the median lobe on sternum 7 (females of the other four species have a clearly notched posterior margin on sternum 7). Distribution. Vietnam : Quang Binh (first record), Da Nang (first record), Ninh Thuan (first record), Gia Lai , Lam Dong , Kon Tum (first record), Quang Ngai (first record) ( Fig. 138 ). Extralimital records: Hainan Island ( China ), Laos (first record).