Phylogenetic Relationships of Acanthocephala Based on Analysis of 18S Ribosomal RNA Gene Sequences

Abstract. Acanthocephala (thorny-headed worms) is a phylum of endoparasites of vertebrates and arthropods, included among the most phylogenetically basal tripoblastic pseudocoelomates. The phylum is divided into three classes: Archiacanthocephala, Palaeacanthocephala, and Eoacanthocephala. These classes are distinguished by morphological characters such as location of lacunar canals, persistence of ligament sacs in females, number and type of cement glands in males, number and size of proboscis hooks, host taxonomy, and ecology. To understand better the phylogenetic relationships within Acanthocephala, and between Acanthocephala and Rotifera, we sequenced the nearly complete 18S rRNA genes of nine species from the three classes of Acanthocephala and four species of Rotifera from the classes Bdelloidea and Monogononta. Phylogenetic relationships were inferred by maximum-likelihood analyses of these new sequences and others previously determined. The analyses showed that Acanthocephala is the sister group to a clade including Eoacanthocephala and Palaeacanthocephala. Archiacanthocephala exhibited a slower rate of evolution at the nucleotide level, as evidenced by shorter branch lengths for the group. We found statistically significant support for the monophyly of Rotifera, represented in our analysis by species from the clade Eurotatoria, which includes the classes Bdelloidea and Monogononta. Eurotatoria also appears as the sister group to Acanthocephala.

[1]  M. P. Cummings,et al.  Sampling properties of DNA sequence data in phylogenetic analysis. , 1995, Molecular biology and evolution.

[2]  M. Telford,et al.  Gnathostomulida--an enigmatic metazoan phylum from both morphological and molecular perspectives. , 1998, Molecular phylogenetics and evolution.

[3]  E. Marcus.  On the Evolution of the Animal Phyla , 1958, The Quarterly Review of Biology.

[4]  A. Graybeal,et al.  Is it better to add taxa or characters to a difficult phylogenetic problem? , 1998, Systematic biology.

[5]  L. Hyman,et al.  The Invertebrates Vol Ii , 1951 .

[6]  O. Amin.  Key to the families and subfamilies of Acanthocephala, with the erection of a new class (Polyacanthocephala) and a new order (Polyacanthorhynchida). , 1987, The Journal of parasitology.

[7]  C. Ricci,et al.  A Cladistic Analysis of Pseudocoelomate (Aschelminth) Morphology , 1996 .

[8]  R. de Wachter,et al.  18S rRNA data indicate that Aschelminthes are polyphyletic in origin and consist of at least three distinct clades. , 1995, Molecular biology and evolution.

[9]  Dustin England,et al.  Nucleotide sequence of the small subunit ribosomal RNA-encoding gene from Opisthorchis viverrini. , 1991, Gene.

[10]  Çîîëîãèÿ áåñïîçâîíî÷íûõ,et al.  Invertebrate Zoology , 1927, Nature.

[11]  N. B. Petrov,et al.  Phylogeny of Nematoda and Cephalorhyncha Derived from 18S rDNA , 1998, Journal of Molecular Evolution.

[12]  H. Segers,et al.  Phylogenetic relationships of phylum Rotifera with emphasis on the families of Bdelloidea. , 1998 .

[13]  B. Vogelstein,et al.  Preparative and analytical purification of DNA from agarose. , 1979, Proceedings of the National Academy of Sciences of the United States of America.

[14]  M. P. Cummings,et al.  Genes and other samples of DNA sequence data for phylogenetic inference. , 1999, The Biological bulletin.

[15]  F. Sanger,et al.  DNA sequencing with chain-terminating inhibitors. , 1977, Proceedings of the National Academy of Sciences of the United States of America.

[16]  Paul H. Harvey,et al.  New uses for new phylogenies , 1993, European Review.

[17]  D. Higgins,et al.  See Blockindiscussions, Blockinstats, Blockinand Blockinauthor Blockinprofiles Blockinfor Blockinthis Blockinpublication Clustal: Blockina Blockinpackage Blockinfor Blockinperforming Multiple Blockinsequence Blockinalignment Blockinon Blockina Minicomputer Article Blockin Blockinin Blockin , 2022 .

[18]  N. Saitou,et al.  The neighbor-joining method: a new method for reconstructing phylogenetic trees. , 1987, Molecular biology and evolution.

[19]  S. Morris,et al.  THE ORIGINS AND EVOLUTION OF THE ACANTHOCEPHALA , 1982 .

[20]  Phylogenetic relationships within phylum Rotifera: orders and genus Notholca , 1989 .

[21]  V. I. Petrochenko.  Acanthocephala of domestic and wild animals , 1971 .

[22]  S. Nadler,et al.  Phylogenetic relationships of the Acanthocephala inferred from 18S ribosomal DNA sequences. , 1998, Molecular phylogenetics and evolution.

[23]  S. Morris.  The origins and relationships of lower invertebrates , 1983 .

[24]  F. Stringfellow,et al.  Cloning and characterization of ribosomal RNA genes from three species of Haemonchus (Nematoda: Trichostrongyloidea) and identification of PCR primers for rapid differentiation. , 1994, Experimental parasitology.

[25]  J. William Ahwood,et al.  CLASSIFICATION , 1931, Foundations of Familiar Language.