Phylogenetic relationships among genera of the Tetrabothriidae (Eucestoda).

Cladistic analysis of the generic-level relationships within the family Tetrabothriidae was conducted. A single cladogram resulted from evaluation of 28 homologous transformation series representing 41 character states. The genus Tetrabothrius was recognized as plesiomorphic followed by Chaetophallus and Trigonocotyle. The latter was considered as the sister group for the remaining tetrabothriid genera of marine mammals. Anophryocephalus, Strobilocephalus, and Priapocephalus are among the most highly derived genera and are postulated as having close evolutionary affinities. Comparisons to previous explicit hypotheses for relationships among the genera indicated the present analysis was the most efficient phylogenetic statement (consistency index = 85.4%) for the 28 attributes evaluated. The recognition of Tetrabothrius as primitive and a natural grouping of Anophryocephalus, Strobilocephalus, and Priapocephalus in part confirmed results of previous studies of the Tetrabothriidae.