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Phylogeny of six oligohymenophoreans (Protozoa, Ciliophora) inferred from small subunit rRNA gene sequences
Author(s) -
Yi Zhenzhen,
Song Weibo,
Gong Jun,
Warren Alan,
AlRasheid Khaled A. S.,
AlArifi Saud,
AlKhedhairy Abdulaziz A.
Publication year - 2009
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/j.1463-6409.2008.00371.x
Subject(s) - biology , polyphyly , phylogenetic tree , phylogenetics , ribosomal rna , evolutionary biology , genetics , zoology , gene , clade
The small subunit rRNA (SSrRNA) genes of six marine oligohymenophoreans, namely Uronemella filificum , Schizocalyptra sp.‐WYG07060701, Schizocalyptra aeschtae , Pleuronema sinica , P. czapikae and Paratetrahymena sp., were sequenced. Phylogenetic trees were constructed with four different methods to assess the inter‐ and intrageneric relationships among the scuticociliates and the phylogenetic assignment of the order Loxocephalida. The SSrRNA phylogeny indicates that: (i) Paratetrahymena is most closely related to Cardiostomatella ; (ii) the order Loxocephalida and the family Uronematidae both appear to be polyphyletic; (iii) the order Philasterida is a well‐defined taxon; (iv) Cyclidium porcatum falls outside the order Pleuronematida in all analyses; (v) the validity of the genus Uronemella is confirmed; (vi) Schizocalyptra is a member of the family Pleuronematidae. Furthermore, the predicted secondary structures of the variable region 4 of the SSrRNA gene sequences show that the size of the terminal bulge in Helix E23–7 is probably different for the orders Philasterida and Pleuronematida. Also, compared to Uronema and Homalogastra , Uronemella has distinct patterns in Helices E23–1, E23–7, E23–8 and E23–9.