泽蛙原蛙片虫的形态学研究

THE MORPHOLOGY OF PROTOOPALINA LIMNOCHARIS NIE, 1932 FROM FEJERVARYA LIMNOCHARIS

  • 摘要: 对采自湖北省洪湖地区的泽蛙(Fejervarya limnocharis)肠道内寄生的泽蛙原蛙片虫进行了形态学再描述, 包括活体形态、固定染色标本形态及扫描电镜下超微结构。样本形态特征参数值与Nie(倪达书)首次发现并命名时所记述标本参数值颇为相符(包括体长、体宽, 核长、核宽)。此外, 本文对2个重要的分类特征进行了补充和修正: (1)缝线位于虫体顶端, 贯穿背腹侧; 所有体动基列均从缝线两侧发出。(2)胞核分裂时在两新核间产生的连接细丝, 在虫体整个生活周期一直存在。并针对这2点特征与其他已知的原蛙片虫属种类进行了比较和讨论: 认为缝线结构是较为稳定的分类特征之一, 体动基列均由此处生发并与虫体纵轴平行延伸; 推测泽蛙原蛙片虫子代虫体中的2个胞核均来自于母体中同一个核, 而其2核间的连接细丝可能是胞核分裂进化历程中比较原始的残迹。

     

    Abstract: This study completely descripted Protoopalina limnocharis Nie 1932 at both light and scanning electron microscope levels. These parasites were collected from the frogs Fejervarya limnocharis from Honghu Lake, Hubei Province, China in July 2016. The body of P. limnocharis was elongated and somewhat ribbon-like in shape, with its length/width ratio about 10﹕1. The widest position of the body was at a region slightly anterior to the middle, while it tapers at both ends. The body surface was thickly flagellated. All the somatic kineties converge on the falx, anteriorly, and many extend to the posterior extremity and number 30﹕40 in total. The falx, composed of a narrow band of kinetosomes, observed in protargol-impregnated specimens at a higher magnification that located at the margin of the anterior pole and extends to both dorsal and ventral sides. Two oval-shaped nuclei observed inP. limnocharis, one of which is situated at the anterior while the other is in the middle. The two nuclei were connected by a long thin thread, which is formed in the process of nuclear division and kept during all the life history of the opalinids. These two aforementioned characteristics were compared between P. limnocharis and its congeners, such as P. caudata michyla, P. heleophrynes, P. pomacantha and P. quadrinucleata. The feature of falx is constant to the opalinids’ taxonomy. Besides, the thin thread between two nuclei of P. limnocharis is the remaining trace during the evolutionary history of nuclear division.

     

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