中华绒螯蟹体表的钟形钟虫重描述及其系统发育地位分析

Redescription and phylogenic analysis of Vorticella campanula attached on Eriocheir sinensis

通过活体观察、蛋白银染色法和硝酸银染色法对附生于中华绒螯蟹(Eriocheir sinensis)上的一种钟形钟虫(Vorticella campanula)的形态学进行了重描述,并且补充了该虫未曾描述过的一些形态学特征,这些补充的特征为:伸缩泡一个,直径为7.5～8.7μm;胞质内分布着自由运动的黄色、绿色、褐色及黑色小颗粒;直径为9～15μm的圆形食物泡;茎宽为5.1～7.6μm;茎内肌丝宽为2.7～3.2μm,肌丝上密集分布着直径为0.5～0.7μm的黑色小颗粒;虫体表膜外侧明显横纹,内侧颗粒状;小膜3外侧2列动基较内侧动基长,小膜2的3列动基等长且终止于小膜1和小膜3的交汇处,小膜1内侧2列动基较外侧动基长;嗜银颗粒明显、密集且分布不均。对钟形钟虫SSUrRNA序列的分子生物学分析对比,与Vorticella campanula(JN120250)的相似率为99.61%。系统发育分析表明,钟形虫属与螅状独缩虫亲缘关系较近,钟形钟虫比同属中其他钟形虫更原始,较早地从钟形虫属中分化了出来。

The morphological characteristics of Vorticella campanula attached on Eriocheir sinensis were redescribed by the observations of living bodies and protargol and silver nitrate impregnated bodies. Some new morphological supplemented characteristics were： One contractile vacuole was 7.5 - 8.7 μm in diameter. Freedom movements of some yellow, green, brown and black granules were within the protoplasm. Food vacuoles were 9 - 15 μm in diameter. Stalks were 5.1 - 7.6μm in width. Myonemes were 2.7 - 3.2μm in width, on which some black granules in the diameter of 0.5 - 0.7μm were densely distributed. The clear striaes were on the outside of pellicle and the granulars were in the inside of pellicle. The outer two kineties were longer than the inner kinety of P3. The three kineties of P2 were equal in length and end of junction of P1 and P2. The outer two kineties were longer than the inner kinety of P1. The argyrophilic grains were obvious and densely and unevenly distributed. Phylogenetic analysis indicates that V. campanula was more original than other Vorticellas and was divided from Vorticella at the earliest stage.