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Phylogenetic analysis of the North American species of Telorchis luehe, 1899 (Cercomeria:Digenea:Telorchiidae)

University of British Columbia

Telorchiids are plagiorchiform intestinal parasites inhabiting turtles, and occasionally snakes and salamanders. Previous taxonomic revisions of the group have been problematical due to a lack of information on intraspecific morphological variation. In the present study, ten of the thirty described North American species are considered valid. Phylogenetic analysis of 22 character states comprising 20 homologous series results in a single phylogenetic tree with a consistency index of 95%. Only one of the characters used in the analysis is homoplasious. In order to maintain a classification that reflects the phylogeny of the group, only one of four proposed genera is recognized. A biogeographical analysis is not feasible due to incomplete collecting records. The two most relatively plesiomorphic telorchiid species are found in salamanders. Five of the eight species from amniotes are considered to have co-speciated with their hosts. One of the secondarily evolved species is postulated to have evolved via a host-switch from turtles to snakes. The other two secondarily evolved species appear to have arisen via sympatric speciation, facilitated by mechanical pre-mating isolation due to a difference in genital pore position. As primarily coevolved telorchiids become more highly derived there is an increase in host specificity, which is consistent with the traditional view of host-parasite relationships.

Text

2010-06-21

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http://hdl.handle.net/2429/25923

Zoology

University of British Columbia

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