Gerris (s. str.) latiabdominis Miyamoto, 1958

Polhemus, J. T., 2012, The water skater genus Gerris Fabricius (Hemiptera: Heteroptera: Gerridae) in Vietnam, with the description of a new species, Zootaxa 3382, pp. 20-28 : 26

Gerris (s. str.) latiabdominis Miyamoto, 1958

Gerris lacustris latiabdominis Miyamoto, 1958: 123 (type locality: Kyushu , Fukuoka, Japan).

Gerris latiabdominis Miyamoto ; Kanyukova, 1982: 86; Andersen & Chen, 1993: 159–160, Figs. 31–34; Andersen, 1993: 2478.

Material examined. VIETNAM: Lao Cai Prov.: 1 female (macropterous), Cat Cat , 1200m, 5km SW of Sa Pa, 22°19.720’N, 103°50.023’E, coll. L. Peregovits & T. Vásárhelyi, 12 Mar. 1998, No. 1 ( MTMB) ; 2 males, 1 female (macropterous), Sa Pa, Hoang Lien NP, Nui Xe , small waterflow, coll. Tran A.D., 2 Jun. 2003, TAD0338 ( ZRC) ; 1 female (macropterous), Sa Pa, waterpools near the upstream of Thac Bac , coll. Tran A.D., 3 Jun. 2003, TAD0343 ( ZRC) ; 1 male (macropterous), Sa Pa, Nui Xe, waterpools near Suoi Vang , coll. Tran A.D., 3 Jun. 2003, TAD0346 ( ZRC) ; 3 females (macropterous), Sa Pa, Hoang Lien N'Park, Sin Chai , coll. Tran A.D., 3 Jul. 2004, TAD0415 ( ZRC) ; 1 male, 1 female (macropterous), Sa Pa, Hoang Lien N'Park, Nui Xe , Suoi Vang, coll. Tran A.D., 4 Jul. 2004, TAD0417 ( ZMHU) ; 2 males, 1 female (macropterous), Sa Pa, Cat Cat, Muong Hoa stream, coll. Tran A.D. & Dinh, T.N.H., 22 Apr. 2011, TAD1102 ( ZMHU) ; 5 males, 4 females (macropterous), Sa Pa, Sin Chai , coll. Tran A.D. & Dinh, T.N.H., 22 Apr. 2011, TAD1103 ( ZMHU) ; 5 males, 1 female (macropterous), Sa Pa, Sin Chai, tributary of Muong Hoa stream, coll. Tran A.D. & Dinh, T.N.H., 22 Apr. 2011, TAD1104 ( ZMHU) .

CHINA: Beijing: 1 female (macropterous), “ China (10), 35km NW Peking, Fragrant Hills” ( NHMW) ; 1 male (macropterous), “ Chenfu Wu. , 1959–186” ( NHMW) . Jilin Prov.: 1 female (macropterous), NE-China, Jilin, near Baihe City, 650m, Erdeo Baihe , coll. Jäch (3), 15 Aug. 1994 ( NHMW) ; 1 male, 2 female (macropterous), NE- China, Jilin, Env. Baihe City , 700m, coll. Jäch (4), 15 Aug. 1994 ( NHMW) ; 2 males, 1 female (macropterous), NE- China, Jilin, Changbaishan , 1400m, coll. Jäch (10), 16 Aug. 1994 ( NHMW) ; 1 female (macropterous), NE-China, Jilin 80km SE Baihe City, Yuanchi , 1100m, coll. Jäch (19), 18 Aug. 1994 ( NHMW) ; 1 male, 1 female (macropterous), NE-China, Jilin 80km SE Baihe City, Yuanchi , 1100m, coll. Jäch (20), 18 Aug. 1994 ( NHMW) .

Liaoning Prov.: 2 males, 1 female (macropterous) , Liaoning, 35km NE Kuandian , 500m, Baishila N.R., coll. Ji & Wang (161), 30 Aug. 1995 ( NHMW) .

TAIWAN: 1 male (macropterous), Taoyuan, Yangmei, coll. L.J. Wang, 31 Oct. 1995 ( NHMW) .

KOREA: 1 female (macropterous), “Consul Haas, Joai, Korea, 1892” ( NHMW) ; 1 female (macropterous), Pyongyang City , Mt. Daesong-san, coll. Dr. H. Steimann & Dr. T. Vásárhelyi, 11 Sep. 1979, No. 522 ( NHMW) ; 1 female (macropterous), Kangwon Prov. , Mt. Kumgang-San, coll. Dr. H. Steimann & Dr. T. Vásárhelyi, 20 Sep. 1979, No. 555 ( NHMW) ; 2 males (macropterous), De Sang-san, 10km NE Pyongyan , netting in water, coll. Dely & Draskovits, 1 Jul. 1977, No. 336 ( NHMW) .

Remarks. Gerris (s. str.) latiabdominis belongs to the G. marginatus species group (sensu Andersen, 1993) which is defined by the following characteristics: pronotum with sub-lateral stripes of silvery pubescence (most species); metasternal area surrounding scent orifice tuberculate or distinctly raised; wing development dimorphic (brachypterous forms normally rare); ventral surface of abdominal segment 8 of male with patches of hairs or lateral impressions; proctiger with short lateral basal process; connexival corners of female usually triangular and pointed. This species group contains six species, mainly from the Nearctic region; G. (s. str.) latiabdominis is the only member of this group found in Palearctic region (Andersen 1993).

Gerris (s. str.) latiabdominis was previously described as a subspecies of Gerris lacustris ( Miyamoto, 1958) , but was raised to specific level by Kanyukova (1982) (see Andersen & Chen 1993). Andersen & Chen (1993) noted that the former can be separated from the latter by several characters: size ( G. latiabdominis is slightly larger); abdominal sterna of both sexes widened and medially impressed, with a median longitudinal ridge; female connexival corners straight, not turned dorsad; female sternum usually dark; macropterous forms dominant, brachypterous forms rare; pronotal lobe not distinctly raised posteriorly, median keel low. However, material from Vietnam presents some variations in terms of color: some males (apterous) without lateral yellow stripes on anterior pronotum; abdominal venter of some females very pale; color of front femur (both males and females) strongly variable, black stripes sometimes reduced, but normally slender compared to material from China and Korea. Therefore, the color of these structures mentioned by Andersen & Chen (1993) cannot reliably separate the two species. Fortunately, other structural characteristics are good enough to differentiate them, notably the form of the abdominal sterna, connexival corners of the female, and the pronotal lobe.

Distribution. Vietnam: Lao Cai (first records for Vietnam!). Others: Eastern Asia.

Habitats. see Habitats for Gerris gracilicornis .