Gammarus nekkensis Uchida, 1935

Hou, Zhong-E & Li, Shuqiang, 2005, Amphipod crustaceans (Gammaridea) from Beijing, P. R. China, Journal of Natural History 39 (36), pp. 3255-3274 : 3258-3260

Gammarus nekkensis Uchida, 1935

Gammarus nekkensis Uchida 1935, p 1 –6; Barnard and Barnard 1983, p 463; Karaman, 1984, p 147 –148; 1989, p 19–35.

Gammarus (Rivulogammarus) nekkensis: Barnard and Dai 1988, p 90 .

Material examined

Beiganchi Village, Fangshan District, collected by Yixiong Cai: four males, four females and three juveniles, 7 December 1992; 92 males, 75 females and eight juveniles, 7 December 1992 ; 75 males and 56 females, 7 December 1992. Between Shidu and Yesanpo Scenic Area , Fangshan District: two males and one female, 12 May 2000 , collected by Shuqiang Li. A sump from Baicaopang, Yesanpo Scenic Area , Fangshan District: two males and two females, 13 May 2000 , collected by Shuqiang Li. A spring near Wanglaopu Village , Liudu Town, Fangshan District: eight males, 10 females and five juveniles, 24 November 2003 , collected by Shuqiang Li. A spring about 2 km from the west of Baiyu Village , Mentougou District: 50 males, 41 females and 15 juveniles, 13 October 2001 , collected by Shuqiang Li and Kaibaryer Meng. A sping near Shangqingshui Village , Mentougou District: 133 males, 101 females and 23 juveniles, 13 October 2001 , collected by Shuqiang Li and Kaibaryer Meng. Longmen Gully, Yanjiatai Village , Mentougou District: 14 males, two females and five juveniles . Xiaolongmen Forestry Centre, Mentougou District : 42 males, 16 females and nine juveniles, 2 October 2004 , collected by Yucheng Lin and Kaibayer Meng. A spring beside Longquanyu Great Wall , Yanqing County: 65 males, 33 females and 20 juveniles, 27 October 2001 , collected by Kevin Li, Ye Tao and Kaibaryer Meng. Maquan Spring, Shangbanquan Town , Yanqing County: 124 males, 164 females and 30 juveniles, 26 August 2001 , collected by Shuqiang Li and Guoqiang Zhang. Guanting Reservoir, Heilongmiao Village , Yanqing County: 38 males and 34 females, 18 May 2004 , collected by Shuqiang Li and Zhong-E Hou. A spring at foot of hill, near Baihe Village , Changping District: six males, five females and 15 juveniles, 3 December 2001 , collected by Shuqiang Li and Zhong-E Hou. Huanglou Fall, Baiyanggou , Changping District: 35 males, nine females and 30 juveniles, 20 October 2001 , collected by Shuqiang Li and Zhong-E Hou. A spring of upper stream of Xiangtan Reservoir , Changping District: 220 males, 153 females and 20 juveniles, 20 October 2001 , collected by Shuqiang Li and Zhong-E Hou. Huyu Spring , Changping District , collected by Yixiong Cai: five males, 4 November 1992; 12 males, 20 females and 15 juveniles, 4 December 1992 . A spring of Duijiuyu Scenic Area , Changping District: 42 males and 24 females, 5 November 1992 , collected by Yixiong Cai. Zhenzhu Spring, Huairou District : 123 males, 121 females and 15 juveniles, 2 June 2001 , collected by Shuqiang Li. Huamu Spring, Huamu Village, Huairou District : 53 males, 25 females and 35 juveniles, 2 June 2001 , collected by Shuqiang Li. Lianhuachi Spring, Yanqi Town, Huairou District : 57 males, 61 females and nine juveniles, 2 June 2001 , collected by Shuqiang Li. A brook between Li Village and Detian Village, Huairou District , collected by Shuqiang Li: 39 males, 13 females and two juveniles, 26 May 2001; 109 males, 114 females and nine juveniles, 26 May 2001 . A spring near Yudaohe Village , Huairou District , collected by Guoqiang Zhang: 300 males, 289 females and 75 juveniles, 26 May 2001; 20 males and 20 females, 26 May 2001 . Jinglinggu, Sihetang Town , Miyun County: eight males and seven females, 1 December 1992 , collected by Yixiong Cai. Sihetang Village, Miyun County: 16 males, five females and nine juveniles, 26 December 1994 , collected by Yixiong Cai. Liukeyu Village , Sihetang Town, Miyun County, collected by Yixiong Cai: 52 males, 21 females and 12 juveniles, 1 December 1992 ; 21 males, 34 females and 10 juveniles, 1 December 1992 . Xianren Fall, Huangtuliang Village , Sihetang Town, Miyun County: 54 males, 12 females and three juveniles, 30 November 1992 , collected by Yixiong Cai. Huangcaowa Village , Pinggu District, collected by Yixiong Cai: 65 males and 42 females, 7 December 1992 ; 14 males and 10 females, 2 December 1992 . Hudongshui Lake , Pinggu District , collected by Yixiong Cai: 51 males and 19 females, 2 December 1992; 13 males and seven females, 2 December 1992 .

Diagnosis

Antennae 1 and 2 with few setae, calceoli present in male; merus to propodus of pereopod 3 with long curled setae on posterior margin; pereopods 5–7 with few setae on anterior margin; epimeral plates 1–3 with blunt posterodistal corners; inner ramus of uropod 3 reaching about 50% of length of outer ramus, outer margin of outer ramus in uropod 3 with long simple setae only.

Remarks

Gammarus nekkensis , widely distributed in North China, was first described based on material from Wuling Mountain, Hebei Province, after which it was reviewed in detail by Karaman (1989) based on specimens from Beijing. The present material accords well with the figures and description given by Karaman (1989), except for the variable numbers and length of setae on the margins of the uropods and urosomites. These features may be variable characters within the species.

Family PSEUDOCRANGONYCTIDAE Holsinger, 1989