摘要：
Euplotids are the most complex and highly differentiated group of ciliates.In order to further explore the species diversity of euplotids,the morphology and morphogenesis of Euplotes aediculatus,collected from Small West Lake of Qingdao,were investigated using live observations,protargol,and silver nitrate impregnation.Based on the detailed morphological and morphogenetic data,the small subunit ribosomal rDNA (SSU rDNA) was sequenced for E.aediculatus.The species is characterized by the following features:nine frontoventral,five transverse,two left marginal,and two caudal cirri,eight dorsal kinetics,and a silverline system of the double-eurystomus type.The main morphogenetic features during division are as follows:(1) the oral primordium of the opisthe develops de novo within a pouch beneath the cortex,the parental adoral zone of membranelles is entirely kept by the proter;(2) fronto-ventral-transverse cirral anlagen (FVTA) Ⅱ-Ⅵ form cirri in the mode of 3:3:3:2:2;(3) frontal cirrus I/1 of the proter and opisthe is generated from the anlage formed de novo;(4) marginal cirri anlagen are formed de novo;(5) the primary dorsal kinety anlagen are from the dedifferentiation of several bristles in the middle of each parental dorsal kinety;(6) the right-most two dorsal kinety anlagen and parent dorsal kineties contribute to two caudal cirri for the proter and the opisthe,respectively.All of these features showed the high conservation of the ontogenetic process in the genus Euplotes.Sequence comparison and phylogenetic analyses based on SSU rDNA revealed a close relationship among Euplotes aediculatus,E.eurystomus,E.amieti,and E.woodruffi,which is consistent with their similar morphology.%游仆类是纤毛虫中进化最为复杂和高等的一大类群,为了进一步探索和完善游仆类的多样性,本研究利用活体观察、蛋白银和银浸法染色技术对采自青岛小西湖的小腔游仆虫(Euplotes aediculatus)的形态学及细胞发生学进行了详尽的研究,并在完整的形态学及发生学研究基础上,测定了小腔游仆虫的核糖体小亚基基因(SSU rDNA)序列,通过序列比较和分子系统树构建等方法,对小腔游仆虫的系统地位进行了分析.结果表明:本种鉴别特征为9根额腹棘毛,5根横棘毛,2根缘棘毛,2根尾棘毛,8列背触毛,double-eurystomus型银线系.发生学特征包括:(1)后仔虫口原基在表皮下独立发生,前仔虫完全继承老口围带;(2)额-腹-横棘毛原基从左向右按照3:3:3:2:2的模式形成额腹棘毛和横棘毛;(3)前后仔虫最左侧额腹棘毛分别由独立产生的原基形成;(4)缘棘毛原基独立发生;(5)初级背触毛原基来自虫体中部老结构的反分化;(6)前后仔虫尾棘毛分别来自最右侧2列背触毛原基和老背触毛列末端;这些特征显示出游仆虫属个体发生模式的高度保守性.分子系统分析与形态学数据一致,即游仆虫属为单元发生,且小腔游仆虫与艾美游仆虫(Euplotes amieti)、阔口游仆虫(E.eurystomus)和伍氏游仆虫(E.woodruffi)聚在一起.
