Data from: Morphometric discrimination of two allozymically diagnosed sibling species of the Echinorhynchus gadi Zoega in Muller complex (Acanthocephala) in the North Sea.

Allozyme electrophoresis was used to detect biological species of the E. gadi complex from gadids from the northern North Sea. A fixed difference at one of nine enzyme loci surveyed confirmed the existence of two reproductively isolated, sympatric species. Mixed infections of two E. gadi spp. (termed A and B) were observed in Gadus morhua and Pollachius virens. E. gadi sp. B was also found in Melanogrammus aeglefinus and Merlangius merlangus. The presence of gravid females of E. gadi spp. A and B in the same host species, P. virens, and sometimes in the same host individual, indicates that neither differential host-specificity nor seasonal differences in mating time are responsible for their reproductive isolation. Morphological study of probosces from electrophoretically identified specimens demonstrated that the two species can be discriminated in graphical and cluster analyses of hook morphometrics. E. gadi sp. I (of Vainola etal., 1994) and E. gadi sp. A are probably conspecific.

本研究采用同工酶电泳（Allozyme electrophoresis）技术，对北海南部鳕科鱼类体内的E. gadi类群（E. gadi complex）开展物种鉴定。在所检测的9个酶位点（enzyme loci）中，有1个位点存在固定差异，证实该类群包含两个生殖隔离（reproductively isolated）的同域物种（sympatric species）。在大西洋鳕（Gadus morhua）与绿青鳕（Pollachius virens）体内，均观察到被分别命名为A、B的两种E. gadi物种的混合感染现象，E. gadi物种B还在黑线鳕（Melanogrammus aeglefinus）和牙鳕（Merlangius merlangus）体内被检出。在同一宿主物种绿青鳕（P. virens）体内，甚至部分同一宿主体内同时存在E. gadi物种A与B的怀卵雌虫（gravid females），这表明宿主特异性差异与交配时间的季节性差异均非二者生殖隔离的成因。对经电泳鉴定的标本的吻部（proboscises）进行形态学研究后发现，通过对钩形度量（hook morphometrics）开展图形分析与聚类分析（cluster analyses），可有效区分这两个物种。Vainola等人1994年报道的E. gadi物种I与E. gadi物种A大概率为同种（conspecific）。