Biodiv Sci ›› 2017, Vol. 25 ›› Issue (5): 549-560.  DOI: 10.17520/biods.2017045

• Original Papers: Animal Diversity • Previous Articles    

Morphology, ontogeny and molecular phylogeny of Euplotes aediculatus Pierson, 1943 (Ciliophora, Euplotida)

Xue Zhang1, Yurui Wang1, Yangbo Fan1,2, Xiaotian Luo1, Xiaozhong Hu1, Feng Gao1,*()   

  1. 1 College of Fisheries, Ocean University of China, Qingdao, Shandong 266003
    2 School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055;
  • Received:2017-02-18 Accepted:2017-04-17 Online:2017-05-20 Published:2017-06-06
  • Contact: Gao Feng


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 kineties, 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.

Key words: ciliates, Euplotes aediculatus, morphology, morphogenesis, phylogeny, small subunit ribosomal rDNA (SSU rDNA)