Metrocoris bilobatoides 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 : 116-119

Metrocoris bilobatoides Chen & Nieser, 1993

( Figs. 1, 2 , 5, 6 , 33 , 47–51 )

Metrocoris bilobatoides Chen & Nieser, 1993: 20–21 , Figs. 48, 52–53 , 60–62 (type locality: Tam Dao , Vinh Phuc, Vietnam).

Material examined. VIETNAM: Ha Giang Prov.: 2 males, 1 female (apt) , 1 male (mpt), Vi Xuyen, Xin Chai commune, Da stream by the road from Thanh Thuy to Lao Chai, coll. Tran A.D. et al., 09 May 2014, TAD1405 ( ZMHU) ; 3 males, 1 female (mpt), Bac Quang, km 13 road 177, Tan Lap commune, waterfall & stream, ca. 86 km to Coc Pai town , coll. Tran A.D. et al., 10 May 2014, TAD1410 ( ZMHU) ; 1 male (apt), 1 male, 1 female (mpt), Hoang Su Phi, Nam Ty commune, bridge at km 34 road 177, waterfall & stream, ca. 65 km to Coc Pai, coll. Tran A.D. et al., 10 May 2014, TAD1411 ( ZMHU) ; 3 males, 3 females (apt), 4 males, 1 female (mpt), Xin Man, Nam Dan commune, Thac Tien - Deo Gio, stream 100 m below waterfall, coll. Tran A.D. et al., 11 May 2014, TAD1413 ( ZMHU) ; 1 female (apt), Xin Man, Nam Dan commune, Thac Tien - Deo Gio, waterfall & stream, coll. Tran A.D. et al., 11 May 2014, TAD1414 ( ZMHU) . Lao Cai Prov.: 1 female (apt), Sa Pa, Nui Xe, small waterflow near the Forest Ranger Station , coll. Tran A.D., 2 June 2003, TAD0339 ( ZRC) ; 1 male (mpt), Sa Pa, Hoang Lien N’Park, Sin Chai, coll. Tran A.D., 1 June 2003, TAD0337 ( ZRC) ; 3 males, 2 females (apt), Sa Pa, Hoang Lien N’Park, Sin Chai, coll. Tran A.D., 3 July 2004, TAD0415 ( ZRC) ; 4 males, 5 females (apt), Cat Cat, 1200 m asl, 5 km SW. of Sa Pa, 22°19.720′N 103°50.023′E, coll. L. Peregovits & T. Vásárhelyi, 12 March 1998, No. 1 ( MTMB) ; 22 males, 32 females (apt), 2 males, 3 females (mpt), rocky river and tributary 7 km NE. of Sa Pa on Lào Cai road, 1220 m asl, 22°22′19″N, 103°52′16″E, water temp. 17°C, 7 April 2000, 0830–1000 hrs., CL 4395, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen ( USNM, BPBM) ; 2 females (apt), rocky streamlet with cascades, 16 km NW. of Sa Pa on Lai Chau road, 1890 m asl, 22°21′28″N, 103°46′37″E, water temp. 17°C, 8 April 2000, 1315–1330 hrs., CL 4402, D.A. Polhemus, J.T. Polhemus & P. Nguyen ( USNM, BPBM) ; 26 males, 20 females (apt), 1 female (mpt), rocky stream 12 km NW. of Sa Pa on Lai Chau road, 1815 m asl, 22°22′22″N, 103°47′35″E, water temp. 18.5°C, 8 April 2000, 1530–1645 hrs., CL 4404, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen ( USNM, BPBM) ; 1 male (apt), cascading stream 20 km NE. of Sa Pa on Lào Cai road, 565 m asl, 22°26′20″N, 103°55′36″E, water temp. 19°C, 9 April 2000, 1215–1430 hrs., CL 4406, coll. D.A. Polhemus, J.T. Polhemus & P. Nguyen ( USNM, BPBM) ; 2 males, 1 female (apt), Sapa area , small stream crossing road from Quy Hô to Ta Giang Phinh, 9 May 1995, coll. D. Currie, B. Hubley & J. Swann, ROM 956023, hemock forest, second growth ( USNM) ; 1 male (apt), Sa Pa, Cat Cat, Muong Hoa stream, coll. Dinh N.H. et al., 22 April 2011, DNH11.01 ( ZMHU) ; 1 male, 1 female (apt), 1 male, 1 female (mpt), Sa Pa, Sin Chai, Muong Hoa stream, coll. Dinh N.H. et al., 22 April 2011, DNH11.03 ( ZMHU) ; 1 male (apt), Sa Pa, Sin Chai, feeder stream of Muong Hoa stream, coll. Dinh N.H. et al., 22 April 2011, DNH11.04 ( ZMHU) ; 1 male (apt), Sa Pa, O Quy Ho pass, stream and waterfall, ca. 9 km from Sa Pa town , coll. Dinh N.H. et al., 23 April 2011, DNH11.11 ( ZMHU) ; 1 male, 1 female (mpt), Sa Pa, Ban Den, Ta Van, Muong Hoa stream, coll. Dinh N.H. et al., 24 April 2011, DNH11.13 ( ZMHU) ; 1 male, 2 females (apt), Sa Pa, Ban Ho, Nam Pu stream 2, coll. Dinh N.H. et al., 22 October 2012, DNH12.02 ( ZMHU) ; 1 male, 1 female (apt), Sa Pa, Seo Trung Ho stream, coll. Dinh N.H. et al., 22 October 2012, DNH12.05 ( ZMHU) ; 1 male, 2 females (apt), Sa Pa, Thanh Phu, near junction of Nam Cang and Muong Hoa streams, coll. Dinh N.H. et al., 23 October 2012, DNH12.06 ( ZMHU) ; 1 female (apt), Sa Pa, Nam Sai, Seo Nam Sai stream 1, coll. Dinh N.H. et al., 24 October 2012, DNH12.09 ( ZMHU) ; 3 females (apt), Sa Pa, Ban Ho, Nam Pu stream (feeder stream of Muong Hoa stream), site 1, at lower section, coll. Tran A.D. et al., 26 October 2013, TAD1361 ( ZMHU) ; 7 males, 7 females (apt), Sa Pa, Sin Chai, Sin Chai stream, site 1, coll. Tran A.D. et al., 27 October 2013, TAD1363 ( ZMHU) ; 2 males, 4 females (apt), Sa Pa, Sin Chai, Sin Chai stream, site 2, feeder stream, coll. Tran A.D. et al., 27 October 2013, TAD1364 ( ZMHU) ; 1 female (apt), 1 male (mpt), Sa Pa, Sin Chai, Muong Hoa stream (Cát stream), coll. Tran A.D. et al., 27 October 2013, TAD1365 ( ZMHU) ; 2 females (apt), Sa Pa, Cat Cat, Ho stream (feeder stream of Muong Hoa stream), coll. Tran A.D. et al., 27 October 2013, TAD1366 ( ZMHU) ; 2 males, 4 females (apt), Sa Pa, Cat Cat, Muong Hoa stream (Cát stream), coll. Ngo Q.H. et al., 27 October 2013, TAD1367 ( ZMHU) ; 2 males (apt), 1 female (mpt), Sa Pa, Trung Chai, km119 Nat. Road #4D, coll. Ngo Q.H. et al., 28 October 2013, TAD1370 ( ZMHU) . Vinh Phuc Prov.: 5 males, 2 females (apt), Tam Dao, 1200 m asl, coll. Vásárhelyi, 14 October 1986, No. 50 ( MTMB, NHMW) ; 2 males (mpt), Vinh Phu, Tam Dao, 1200 m asl, coll. M. Josifov, 8 April 1978 ( NHMW) ; 1 male (apt), Tam Dao, forest stream, 1000–1100 m asl, coll. Papácek, 17 May 1995 ( NHMW) ; 12 males, 10 females (apt), 13 males, 10 females (mpt), Vinh Phu, Tam Dao, coll. L. Dembicky, 9–18 May 1996 ( NHMW) ; 1 female (apt), 2 females (mpt), 21°27′N 105°39′E, 70 km NW. Hanoi, Tam Dao, 900–1200 m asl, coll. Pacholátko & Dembicky, 9–19 May 1996 ( NHMW) ; 2 males, 1 female (apt), Tam Dao, 1200 m asl, coll. Vásárhelyi, 12 October 1986, No. 26 ( MTMB) ; 3 males (apt), Tam Dao, 1200 m asl, on light, coll. Vásárhelyi, 13 October 1986, No. 37 ( MTMB) ; 7 males, 11 females (apt), 3 males (mpt), Tam Dao N’Park, Suoi Mo (upstream of Thac Bac waterfall), coll. Tran A.D., 16 June 2003, TAD0350 ( ZRC) ; 8 males, 7 females (apt), 2 females (mpt), Tam Dao N’Park, Thac Bac stream (near Doi Che), coll. Tran A.D., 17 June 2003, TAD0351 ( ZRC) ; 7 males, 6 females (apt), 3 males, 4 females (mpt), Tam Dao N’Park, Suoi Bua Lon (Bua Lon stream), coll. Tran A.D., 19 June 2003, TAD0356 ( ZRC) ; 2 males, 3 females (apt), 1 male (mpt), stream at Tam Dao, NW. of Hanoi , 940 m asl, vic. 21°27′53″N, 105°38′45″E,water temp. 17°C, 18 March 2000, CL 4359, coll. J.T. Polhemus & P. Nguyen ( USNM) ; 1 male, 1 female (apt), waterfall below Tam Dao, NW. of Hanoi , 870 m asl, 21°27′11″N, 105°38′35″E, water temp. 17°C, 18 March 2000, CL 4360, coll. J.T. Polhemus & P. Nguyen ( USNM, BPBM) . Ninh Binh Prov.: 1 male, 1 female (apt), Cuc Phuong, 400 m asl, coll. Vásárhelyi, 17 October 1986, No. 68 ( MTMB) .

Diagnosis. Male: fore femur moderately incrassate (variations existed, ratio length/width about 3.60–4.75), indentation on ventral surface with small tooth on proximal edge, and a stout sub-apical tooth (in more slender fore femur, indentation usually smaller, Figs. 47, 48 ). Male genitalia large: segment 8, pygophore and proctiger elongate; paramere prominent, falciform with pointed apex ( Fig. 33 ), endosoma as in Chen & Nieser (1993: Fig. 62 ). Female: tergum 7 sub-triangular, sometimes apex medially produced ( Figs. 49, 50 ); sternum 7 large, posterior part constricted and produced two separate lobes, sometimes curved dorsad, completely enclosing genitalia, the notch between two lobes narrow, angular ( Fig. 51 ).

Size: apterous males: length 5.3–5.8, width 2.38–2.81, macropterous males: length 6.6–7.6, width 2.29–2.64 (mpt); apterous females: length 4.8–5.6, width 2.57–2.87, macropterous females: length 6.3–6.8, width 2.62–2.77.

Remarks. The specimens from Lao Cai Prov. present some structural variations in regard to tergum 7 of the female. In the female specimens from this locality, tergum 7 has its apex distinctly produced ( Fig. 50 ), while female specimens from the type locality have the apex only slightly produced ( Fig. 49 ). Other characters (endosoma, fore leg, parameres of the male, sternum 7 of the female) indicate that these populations are conspecific, with the variations in tergum 7 representing intra-specific variation. For further notes, see Remarks for M. johnpolhemi , new species.

Distribution. Vietnam: Lao Cai, Ha Giang (first record), Vinh Phuc, Ninh Binh ( Fig. 138 ).

Figures

Figs. 1, 2. In situ photographs of Metrocoris bilotatoides, from Vietnam, Vinh Phuc Prov., Tam Dao (photographed by TAD).

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. 44–55. Morphological features of Metrocoris species. 44–46: M. stranguloides. 44, 45: right fore legs of male. 46: sternum 7 of female, ventral view. 47–51: M. bilobatoides. 47, 48: right fore leg of male, same scale. 49, 50: tergum 7 of female, dorsal view (49: specimen from Tam Dao; 50: specimen from Lao Cai). 51: sternum 7 of female, ventral view. 52–55: M. vietnamensis (52–55 reproduced and modified from Tran & Zettel, 2005). 52, 53: right fore legs of male. 54: left paramere. 55: sternum 7 of female, in situ (44, 45, 47, 48, 52, 53 same scale; 46, 49–51, 55 same scale).

Figs. 56–65. Morphological features of Metrocoris johnpolhemi, new species. 56, 57: right fore legs of male. 58: abdominal segment 8 of male, in situ, lateral view. 59: pygophore, lateral view. 60: proctiger of male. 61: left paramere. 62, 63: endosomal sclerites, lateral and dorsal views. 64: tergum 7 of female, dorsal view. 65: sternum 7 of female, ventral view (56, 57 same scale; 58, 59 same scale; 64, 65 same scale).

Fig. 138. Distribution records in Vietnam of Metrocoris stranguloides, M. bilobatoides, M. johnpolhemi, new species, and M. vietnamensis.