SYSTEMATICS OF MESOCESTOIDES (CESTODA: MESOCESTOIDIDAE): EVALUATION OF MOLECULAR AND MORPHOLOGICAL VARIATION AMONG ISOLATES

Authors

Kerry A. Padgett, California Department of Health ServicesFollow
Steven A. Nadler, University of California - DavisFollow
Linda Munson, University of California - Davis
Ben Sacks, University of California - Davis
Walter M. Boyce, University of California - DavisFollow

Date of this Version

2005

Comments

Published by Padgett, Nadler, Munson, Sacks & Boyce in Journal of Parasitology (2005) 91(6). Copyright © American Society of Parasitologists [2005]. Used by permission

Abstract

A hypothesis-based framework was used to test if 3 genetic strains of Mesocestoides (clades A, B, and C) are distinct evolutionary lineages, thereby supporting their delimitation as species. For comparative purposes, 3 established cestode species, Taenia pisiformis, Taenia serialis, and Taenia crassiceps were assessed using the same methods. Sequence data from mitochondrial rDNA (12S) and the second internal transcribed spacer of nuclear rDNA (ITS-2) revealed derived (autapomorphic) characters for lineages representing clade A (n = 6 autapomorphies), clade B (n = 4), and clade C (n = 9) as well as T. pisiformis (n = 15) and T. serialis (n = 12). Furthermore, multivariate analysis of morphological data revealed significant differences among the 3 genetic strains of Mesocestoides and between T. pisiformis and T. serialis. The level of phenotypic variation within evolutionary lineages of Mesocestoides and Taenia spp. tapeworms was similar. Results from this study support recognizing Mesocestoides clades A, B, and C as separate species, and provide evidence that clade B and Mesocestoides vogae are conspecific.