Extreme morphological divergence: Phylogenetic position of a termite ectoparasite

Species of Termitaria are lesion-forming ectoparasites occurring worldwide on a diverse group of termites. The reduced thallus consists of a basal cell layer from which haustorial cells penetrate the termite and a darkly pigmented sporodochium. One species, Termitaria snyderi, has been the subject of several morphological studies, but its phylogenetic position has remained enigmatic. Here we provide evidence of a close relationship between T. snyderi and the morphologically distinct ascomycetes, Kathistes analemmoides and K. calyculata, based on phylogenetic analysis of molecular characters derived from portions of the nuclear-encoded small-subunit ribosomal RNA gene (ssu rDNA) and supplemental evidence from the β-tubulin gene. Trees were derived using parsimony and maximum-likelihood criteria. Bayesian analysis and parsimony bootstrap methods were used to assess support for the tree nodes.