Metrocoris nigrofascioides Chen & Nieser, 1993

A. D., Tran & Polhemus, D. A., 2017, The genus Metrocoris Mayr, 1865 (Gerromorpha: Gerridae) in Vietnam, with descriptions of five new species, Raffles Bulletin of Zoology 65, pp. 109-149 : 127-128

Metrocoris nigrofascioides Chen & Nieser, 1993

( Figs. 16, 17 , 38 , 77–79 )

Metrocoris nigrofascioides Chen & Nieser, 1993: 34–35 , Figs. 90 , 97 , 105 (type locality: Fang, Chiang Mai, Thailand); Zettel & Chen, 1996: 152, 177 (records from Vietnam).

Material examined. VIETNAM: Thanh Hoa Prov.: 1 male (apt) , 1 male, 1 female (mpt), Ben En N’Park, Nhu Xuan, Son Binh , Khe Cay Khe stream, site 1, coll. Pham T.D., 01 March 2013, BE1304 ( ZMHU) . Quang Binh Prov.: 1 male (apt), Phong Nha, upstream of Thac Xoi waterfall, coll. Tran A.D., 15 July 2004, DY0407 ( ZRC) ; 4 males, 2 females (apt), Phong Nha, a stream 1 km behind Forest Ranger station 4, coll. Tran A.D., 16 July 2004, DY0409 ( ZMHU) . Da Nang Prov.: 4 males (apt), Ba Na - Nui Chua foothills, Suoi Lanh , coll. Tran A.D. & Tan H.H., 01 March 2005, THH05-25 ( ZRC) . Kon Tum Prov.: 1 male, 3 females (apt.), stream 2 km inside Chu Mom Ray Nature Reserve , 635 m asl, 14°25′55″N, 107°42′46″E, water temp. 21°C, 4 March 2001, CL 4277, coll. J.T. Polhemus & P. Nguyen ( USNM) ; 2 females (apt), stream 63 km NE. of Kontum on Hwy. 24, 1050 m asl, 14°36′14″N, 108°18′22″E, water temp. 20.5°C, 6 March 2001, CL 4281, coll. J.T. Polhemus & P. Nguyen ( USNM, BPBM) ; 4 males, 6 females (apt), 1 male, 3 females (mpt), stream in dry forest hills 29 km NE. of Kontum on Hwy. 24, 565 m asl, 14°27′01″N, 108°09′12″E, water temp. 20.5°C, 19 March 2001, CL 4284, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen ( USNM) ; 1 female (apt), 1–4 m trib. of Ngoc Mi River, ca. 20 km NE. of Ngoc Linh , 980 m asl, 10 Sept. 1998, coll. B. Hubley, D.C. Currie & M. Tseng, ROM 982314, secondary tropical forest, 15°08′23″N, 107°54′40″E ( USNM) . Gia Lai Prov.: 1 male, 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, 1 female (apt), 1 female (mpt), 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.: 7 males, 8 females (apt) , 1 female (mpt), rocky stream on E. side of An Khe Pass, 19 km E. of An Khe on Hwy. 19, 115– 200 m asl, 13°58′50″N, 108°47′14″E, water temp. 24°C, 12 March 2001, CL 4291, coll. J.T. Polhemus & P. Nguyen ( USNM) ; 1 male, 3 females (apt), waterfall on E. side of An Khe Pass, 19 km E. of An Khe on Hwy. 19, 170 m asl, 13°58′23″N, 108°46′48″E, water temp. 24°C, 12 March 2001, CL 4292, coll. J.T. Polhemus & P. Nguyen ( USNM, BPBM) . Phu Yen Prov.: 1 male (apt), stream in granite hills on N. side of Ca Pass, 29 km S. of Tuy Hoa on Hwy. 1, 60 m asl, 12°53′05″N, 109°23′38″E, water temp. 24°C, 25 March 2001, CL 4316, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen ( USNM) . Lam Dong Prov.: 1 male (apt), Di Linh, 18 km S. of Bao Loc , 600 m asl, coll. Vásárhelyi, 14 October 1988, No. 283 ( MTMB) . Dong Nai Prov.: 2 males 1 female (apt), Vinh Cuu, Vinh An, Suoi Rang waterfall, coll. Tran A.D., 10 May 2003, TAD0315b ( ZRC) . Kien Giang Prov., Phu Quoc Island : 1 male (apt), 1 male (mpt), Da Ban stream & waterfall, coll. Tran A.D. & D. Yeo, 29 November 2010, TAD1020 ( ZMHU) ; 2 males, 1 female (apt), 3 males, 3 females (mpt), Tranh stream (middle section & waterfall), coll. Tran A.D., 30 November 2010, TAD1022 ( ZMHU) .

LAOS: Khammouan Prov.: 3 males, 1 female (apt) , 1 male, 1 female (mpt), Ban Khoun Ngeun env., N18°07′E104°29′, alt. 250 m asl, coll. E. Jendek & P. Patcholátko, 4–16, 25–30 November 2000 ( NHMW) . Saravan Prov.: 1 male, 1 female (apt), Tat Lo Waterfall & Resort, 370 m asl, coll. Schwendinger, 29 December 1996 ( NHMW) . Vientiane Prov.: 1 male, 6 females (apt), Ban Van Heue, ~ 20 km E. of Phou Khao Khouay park HQ, 1039 m asl, vic. 18°17′44″N, 102°53′48″E, 31 August 1967, coll. J.L. Gressit et al. ( BPBM) . Luang Prabang Prov.: 2 females (apt) , 2 males, 5 females (mpt), Huay La stream, (trib. to Nam Xeuang river), NE. of Ban Pha on road to Pak Xeng , 305 m asl, 20°03′38″N, 102°19′45″E, water temp. 26°C, 6 December 2015, 1000–1200 hrs., CL 6026, coll. D.A. Polhemus ( BPBM) ; 5 males, 5 females (apt), 1 male, 2 females (mpt), Huay Sokor stream, (trib. to Nam Xeuang river), NE. of Ban Pha on road to Pak Xeng , 350 m asl, 20°03′11″N, 102°21′43″E, water temp. 25°C, 6 December 2015, 1330–1500 hrs., CL 6027, coll. D.A. Polhemus ( BPBM) ; 1 male (apt), Nam Bor River, 1.3 km SW. of Ban Phuong Pao village , 365 m asl [1200 ft], 19°57′02″N, 102°28′33″E, water temp. 21°C, 7 December 2015, 0930–1015 hrs., CL 6028, coll. D.A. Polhemus ( BPBM) ; 1 female (apt), 1 male, 1 female (mpt), small forest tributary to Nam Bor River, 1.4 km SW. of Ban Phuong Pao village , 395 m asl, 19°56′59″N, 102°28′29″E, water temp. 21°C, 7 December 2015, 1030–1100 hrs., CL 6029, coll. D.A. Polhemus ( BPBM) ; 3 males, 2 females (apt), 4 males, 1 female (mpt), rocky stream and small clear tributary at Ban Kokvane village , upstream of bridge, 320 m asl [1050 ft], 19°57′07″N, 102°17′36″E, water temp. 23.5°C, 7 December 2015, 1315–1415 hrs., CL 6031, coll. D.A. Polhemus ( BPBM) ; 2 males, 2 females (apt), 1 male (mpt), rocky stream at Tad Thang waterfall area,, 7 km S. of Luang Prabang , 410–440 m asl [1350–1450 ft], 19°50′15″N, 102°07′53″E, water temp. 21°C, 8 December 2015, 0900– 1045 hrs., CL 6032, coll. D.A. Polhemus ( BPBM) .

CAMBODIA: Koh Kong Prov.: 4 males, 1 female (apt) , 2 females (mpt), Cardamom Mountains, shaded forest streamlet on road to Tatai Dam overlook, 420 m asl, 11°36′02″N, 103°13′02″E, water temp. 26°C, 30 August 2015, CL 6016, coll. D.A. Polhemus ( BPBM, USNM) ; 3 males, 1 female (mpt), Cardamom Mountains, cascading stream in sandstone bed on road to Tatai Dam overlook, 420 m asl, 11°35′47″N, 103°14′48″E, water temp. 26°C, 30 August 2015, CL 6017, coll. D.A. Polhemus ( BPBM, USNM) ; 2 males, 2 female (apt), Cardamom Mountains, Toeuk Noeng River , 165 m asl, 11°37′33″N, 103°28′51″E, water temp. 26°C, 31 August 2015, CL 6019, coll. D.A. Polhemus ( BPBM, USNM) ; 1 male, 4 female (apt), Cardamom Mountains, outflow from ponded stream on road from Koh Kong to Pursat , 540 m asl, 12°00′58″N, 103°10′47″E, water temp. 24.5°C, 1 September 2015, CL 6023, coll. D.A. Polhemus ( BPBM, USNM) . THAILAND: Chiang Mai Prov.: 1 male (mpt), N. Thailand, 78 km from Chiang Mai , coll. Y.Y. Goh, 12 June 1998, GYY079 ( ZRC) ; 3 males, 4 females (apt), 1 male, 1 female (mpt), NW. Chiang Mai, stream off Pai River , coll. C.M. Yang & T.B. Lim, 08 September 1998, YCM207 ( ZRC) ; 2 males, 2 females (apt), 1 male, 1 female (mpt), W. Mae Rim, Mae Sa N’Park, Mae Sa Falls , coll. H. Zettel (2), 30–31 October 1995 ( NHMW) . Kamphaeng Phet Prov.: 1 male (mpt), central Thailand, Kamphaeng Phet , side stream to waterfall, coll. C.M. Yang & T.B. Lim, 12 September 1998, YCM223 ( ZRC) ; 1 female (apt), central Thailand , rocky stream, coll. C.M. Yang & T.B. Lim, 12 September 1998, YCM222A ( ZRC) .

Diagnosis. Male: fore femur incrassate (ratio length/width variable, about 3.63–4.61), ventral surface indented subapically, with pointed proximal edge and a large sub-apical tooth, inner surface of fore tibia with broad indentation basally (not obvious in males with more slender fore femur) ( Fig. 77 ). Male genitalia moderate in size: pygophore sub-ovate; proctiger elongate; paramere falciform, apex blunt ( Fig. 38 ); endosoma as in Chen & Nieser (1993: Fig. 105 ). Female: inner surface of hind trochanter with long hairs ( Fig. 78 ); sternum 7 large, constricted laterally, posteriorly produced median lobe with parallel lateral margins and round posterior margin, sometimes directed dorsad, completely enclosing genitalia ( Fig. 79 ).

Size: apterous males: length 4.31–4.95, width 2.11–2.51; apterous females: length 4.02–4.75, width 2.23–2.52.

Remarks. See Remarks for M. acutus .

Distribution. Vietnam: Thanh Hoa, Quang Binh, Da Nang, Kon Tum, Gia Lai, Binh Dinh, Phu Yen, Lam Dong, Dong Nai, Phu Quoc ( Fig. 139 ). Extralimital records: Myanmar: Hpungan Sadon, Thailand (northern), Laos (first record), Cambodia (first record).

Figures

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).

Figs. 32–43. Parameres of Metrocoris species. 32: M. stranguloides, specimen from Vietnam, Gia Lai Prov., 60 km N. of An Khe (CL 4309). 33: M. bilobatoides, specimen from Vietnam, Lao Cai Prov., 12 km NW. of Sa Pa (CL 4404). 34: M. johnpolhemi, new species, specimen from Vietnam, Lai Chau Prov., Nam Ceung stream (CL 4409). 35: M. quynhi, specimen from Vietnam, Lao Cai Prov., 18 km NW. of Sa Pa (CL 4400). 36: M. obscurus, specimen from Vietnam, Lao Cai Prov., 4 km NE. of Sa Pa (CL 4407). 37: M. acutus, specimen from Vietnam, Hai Hung Prov., 22 km N. of Chi Linh (CL 4375). 38: M. nigrofascioides, specimen from Vietnam, Binh Dinh Prov., An Khe Pass (CL 4291). 39: M. sicilis, new species, specimen from Vietnam, Hanoi, Ba Vi N’Park (CL 4393). 40: M. triangulatus, specimen from Vietnam, Gia Lai Prov., N. of Tram Lap (ROM-961066). 41: M. ciliatus, paratype, from Vietnam, Lai Chau Prov., Muong Te (TAD1329). 42: M. nigriventris, new species, paratype, from Vietnam, Lao Cai Prov., 20 km NE. of Sa Pa (CL 4406). 43: M. monticola, new species, paratype, from Vietnam, Lao Cai Prov., Sa Pa, Sin Chai (TAD1363).

Figs. 74–79. Morphological features of Metrocoris species. 74–76: M. acutus. 74, 75: right fore legs of male, same scale. 76: sternum 7 of female, ventral view. 77–79: M. nigrofascioides. 77: right fore leg of male. 78: hind trochanter of female. 79: sternum 7 of female, ventral view (74, 75, 77 same scale; 76, 78, 79 same scale).

Figs. 80–90. Morphological features of Metrocoris species. 80–83: M. ciliatus, macropterous male. 80: right fore leg. 81, 82: left paramere, two different views. 83: endosomal sclerites, lateral view. 84, 85: M. inthanon. 84: right fore leg of male. 85: apex of abdomen, female, ventral view. 86–90: M. triangulatus. 86–89: male holotype. 86: A, right fore leg. 87: left paramere. 88, 89: endosomal sclerites, lateral and dorsal views. 90: abdomen of female, ventral view (80, 84, 86 same scale; 81–83 same scale; 85, 90 same scale).

Figs. 94–99. Morphological features of Metrocoris sicilis, new species. 94: right antenna of male. 95: right fore leg of male. 96: left paramere. 97, 98: endosomal sclerites, lateral and dorsal views. 99: abdomen of female, ventral view (94, 95 same scale; 96–98 same scale).

Figs. 100–107. Morphological features of Metrocoris nigriventris, new species. 100: right fore leg of male. 101–103: left paramere, three different views. 104, 105: endosomal sclerites, lateral and dorsal views. 106: hind coxa and trochanter of female. 107: sternum 7 of female, ventral view (101–105 same scale; 106, 107 same scale).

Fig. 139. Distribution records in Vietnam of Metrocoris obscurus, M. quynhi, M. acutus, and M. nigrofascioides.