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Morphology, Phylogeny, and Diversity of Trichonympha (Parabasalia: Hypermastigida) of the Wood-Feeding Cockroach Cryptocercus punctulatus

Authors

  • KEVIN J. CARPENTER,

    1. Canadian Institute for Advanced Research, Botany Department, University of British Columbia, University Boulevard, Vancouver, BC, Canada V6T 1Z4
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  • LAWRENCE CHOW,

    1. Canadian Institute for Advanced Research, Botany Department, University of British Columbia, University Boulevard, Vancouver, BC, Canada V6T 1Z4
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  • PATRICK J. KEELING

    1. Canadian Institute for Advanced Research, Botany Department, University of British Columbia, University Boulevard, Vancouver, BC, Canada V6T 1Z4
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Corresponding Author: P. J. Keeling, Canadian Institute for Advanced Research, Botany Department, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4—Telephone number: +1 604 822 4906; FAX number: +1 604 822 6089; e-mail: pkeeling@interchange.ubc.ca

Abstract

ABSTRACT. Trichonympha is one of the most complex and visually striking of the hypermastigote parabasalids—a group of anaerobic flagellates found exclusively in hindguts of lower termites and the wood-feeding cockroach Cryptocercus—but it is one of only two genera common to both groups of insects. We investigated Trichonympha of Cryptocercus using light and electron microscopy (scanning and transmission), as well as molecular phylogeny, to gain a better understanding of its morphology, diversity, and evolution. Microscopy reveals numerous new features, such as previously undetected bacterial surface symbionts, adhesion of post-rostral flagella, and a distinctive frilled operculum. We also sequenced small subunit rRNA gene from manually isolated species, and carried out an environmental polymerase chain reaction (PCR) survey of Trichonympha diversity, all of which strongly supports monophyly of Trichonympha from Cryptocercus to the exclusion of those sampled from termites. Bayesian and distance methods support a relationship between Trichonympha species from termites and Cryptocercus, although likelihood analysis allies the latter with Eucomonymphidae. A monophyletic Trichonympha is of great interest because recent evidence supports a sister relationship between Cryptocercus and termites, suggesting Trichonympha predates the Cryptocercus-termite divergence. The monophyly of symbiotic bacteria of Trichonympha raises the intriguing possibility of three-way co-speciation among bacteria, Trichonympha, and insect hosts.

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