Phylogenetic Analysis Based on 18S Ribosomal RNA Gene Sequences Supports the Existence of Class Polyacanthocephala (Acanthocephala)

Authors

Martin Garcia-Varela, Instituto de Investigaciones Biomedicas MexicoFollow
Michael P. Cummings, University of Maryland - College ParkFollow
Gerardo Perez-Ponce de Leon, Universidad Nacional Autonoma de MexicoFollow
Scott Lyell Gardner, University of Nebraska - LincolnFollow
Juan P. Laclette, Instituto de Investigaciones Biomedicas MexicoFollow

Date of this Version

5-1-2002

Comments

Published in Molecular Phylogenetics and Evolution 23 (2002): 288-292. Copyright 2002, Academic Press/Elsevier Science (USA). Used by permission.

Abstract

Members of phylum Acanthocephala are parasites of vertebrates and arthropods and are distributed worldwide. The phylum has traditionally been divided into three classes, Archiacanthocephala, Palaeacanthocephala, and Eoacanthocephala; a fourth class, Polyacanthocephala, has been recently proposed. However, erection of this new class, based on morphological characters, has been controversial. We sequenced the near complete 18S rRNA gene of Polyacanthorhynchus caballeroi (Polyacanthocephala) and Rhadinorhynchus sp. (Palaeacanthocephala); these sequences were aligned with another 21 sequences of acanthocephalans representing the three widely recognized classes of the phylum and with 16 sequences from outgroup taxa. Phylogenetic relationships inferred by maximum-likelihood and maximum-parsimony analyses showed Archiacanthocephala as the most basal group within the phylum, whereas classes Polyacanthocephala + Eoacanthocephala formed a monophyletic clade, with Palaeacanthocephala as its sister group. These results are consistent with the view of Polyacanthocephala representing an independent class within Acanthocephala.