The Nematalycidae (Acariformes): an Exploration of Large-Scale Morphological
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The Nematalycidae (Acariformes): An exploration of large-scale morphological variation and evolution using low-temperature scanning electron microscopy DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Samuel J. Bolton Graduate Program in Evolution, Ecology and Organismal Biology The Ohio State University 2016 Dissertation Committee: Hans Klompen, Advisor Norman F. Johnson Meg Daly Copyright by Samuel John Bolton 2016 Abstract The Nematalycidae are among the most bizarre looking arthropods; their extreme body elongation is an especially unusual modification within the Arachnida. However, there have been few attempts to study their morphology in detail. This is partly because there are few available specimens – they live in mineral regolith, which is sampled relatively rarely. But this is also due to their extremely small size and soft integument. The former makes them problematical for examination under a light microscope; the latter renders them inappropriate for conventional scanning electron microscopy. This dissertation is a body of work that attempts to address this knowledge gap via low-temperature scanning electron microscopy (LT-SEM). Chapter 2 is a description of a new genus and species. Chapter 3 addresses how the two main different modes of locomotion, one of which is a novel discovery, correspond with modifications of the integument. Chapters 4 and 5 are concerned with hypotheses on adaptations of the gnathosomas (mouthparts) of three different genera. Chapter 4 includes a hypothesis on a novel form of microbivory, which could explain some of the gnathosomal features of Osperalycus and Gordialycus. Chapter 5 addresses the evolutionary implications of the mouthparts of Cunliffea, which has a rudimentary sheath for chelate (‘biting’) chelicerae. This structure may help to explain how one of the unusual modifications of the Eriophyoidea, a stylet sheath, ii originated. Chapter 6 concerns a phylogenetic analysis of morphological characters. The principal finding is that the Eriophyoidea, a diverse group of plant parasites, are more closely related to the Nematalycidae than any other lineage, and they may even be derived from within the Nematalycidae. Therefore, the unusual, vermiform bodies of these two taxa are shared because of their relatively recent common ancestry, and not because of evolutionary convergence. In the final chapter, the conclusion, I suggest that the Nematalycidae should be promoted from a family to a higher taxonomic rank. This is based on evidence from throughout the dissertation. iii Acknowledgments First and foremost, I would like to thank my advisor, Dr. Hans Klompen. He not only put up with me, educated me, and mentored me, but he also gave me a much valued freedom that has allowed me to take ownership of my research. Whereas he was always available for advice, I am also very grateful for the complete trust and confidence that he has bestowed on me. This PhD would not have been possible without the collaboration of the US Department of Agriculture, which provided the LT-SEM that was essential to this research. I am very thankful to Dr. Gary Bauchan, Dr. Ronald Ochoa and Christopher Pooley, Beltsville Agricultural Research Center, for their technical collaboration. The Smithsonian Institution provided me with a much needed pre-doctoral fellowship, which allowed me to embark on an immensely productive year of research. I would especially like to thank Dr. Jonathan Coddington for being my host while I was based there. Joseph Cora deserves many thanks for his friendship, advice and constructive criticism, and for all the IT aid he provided me whenever I needed it. I also appreciate the help and advice of a number of other key research collaborators, including Dr. Pavel Klimov, University of Michigan, and Dr. Philipp Chetverikov, Saint Petersburg State University, Russia. And I am very grateful for the advice, support and encouragement of Dr. Roy Norton, Dr. Barry OConnor, Dr. David Walter and Dr. Evert Lindquist. Many thanks also go to my iv Acarology Lab mates, Orlando Combita, Dr. Kaitlin Uppstrom and Monica Farfan. Their support and friendship has helped to provide a fantastic setting for my PhD program at The Ohio State University. I would like to thank the faculty of the Department of Evolution, Ecology and Organismal Biology, who have been extremely helpful and supportive. Foremost among them are Dr Meg Daly, Dr Norman Johnson, Dr. John Freudenstein and Dr. John Wenzel. Many thanks also to Dr. Steve Passoa for his help with microscopy. And my fellow graduate students at EEOB deserve many thanks for their support and encouragement (alas, there are too many of them to mention in name). Last, but not least, I would like to thank my parents, Vera and John Bolton, who have had to endure my absence for much of the past six and a half years. I am ashamed to admit I have only been back to visit them, in the UK, four times since I began my PhD program, and I have not received the smallest complaint. This is not for shortage of love but because, as ever, they value my hopes and dreams above their own needs and desires. v Vita 1996 to 2000 ........................... BSc Bioarchaeology, University of Bradford, UK. 2000 to 2001 ........................... MSc Applied Entomology, Imperial College, London, UK. 2002 to 2004 ........................... Company Biologist, Microbee, London, UK. 2004 to 2007 ........................... Freshwater Entomologist, National Museum Wales, Cardiff, UK. 2007 to 2008 ........................... MSc Biosystematics, Imperial College, London, UK. 2009 to present ...................... Graduate Teaching Associate & General Research Associate, Dept. Evol., Ecol., Org. Biol., The Ohio State University Publications Pfliegler, W.P. & Bolton, S.J. 2016. Two new families (Acari: Alicorhagiidae and Platyhelminthes: Prorhynchidae) reported for Hungarian fauna from leaf litter in the Bükk mountains. Opuscula Zoologica Budapest 47, 00-00. Bolton, S.J., Bauchan, G.R., Ochoa, R. & Klompen, H. 2015. A novel fluid-feeding mechanism for microbivory in the Acariformes (Arachnida: Acari), Arthropod Structure and Development 44, 313-325. vi Bolton, S.J., Bauchan, G.R., Ochoa, R., Pooley, C. & Klompen, H. 2015. The role of the integument with respect to different modes of locomotion in the Nematalycidae (Endeostigmata). Experimental & Applied Acarology 65, 149-161. Bolton, S.J. Klompen, H., Bauchan, G.R. & Ochoa, R. 2014. A new genus and species of Nematalycidae (Acari: Endeostigmata). Journal of Natural History 48, 1359-1373. Spies, M. & Bolton, S.J. 2013. On the first record from Britain of Parachironomus elodeae (Diptera, Chironomidae). Dipterists digest 20, 79-85. Walter, D.E., Bolton, S.J., Uusitalo, M. & Zhang, Z.-Q. 2011. Suborder Endeostigmata Reuter, 1909. In: Zhang Z-Q, editor. Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness. Zootaxa, 139-140. Bolton, S.J., Macleod, N. & Edgecombe, G.D. 2009. Geometric approaches to the taxonomic analysis of centipede gonopods (Chilopoda: Scutigeromorpha). Zoological Journal of the Linnean Society 156, 239-259. Field of Study Major Field: Evolution, Ecology and Organismal Biology vii Table of Contents Abstract .......................................................................................................................... ii Acknowledgments ......................................................................................................... iv Vita ............................................................................................................................... vi Table of Contents ........................................................................................................ viii List of Figures .............................................................................................................. xii List of Tables................................................................................................................xiv Chapter 1: Introduction ....................................................................................................1 Chapter 2 Summary: A new genus and species .............................................................2 Chapter 3 Summary: The role of the integument in locomotion ....................................3 Chapter 4 Summary: A novel form of microbivory.......................................................3 Chapter 5 Summary: A sheath for biting chelicerae ......................................................4 Chapter 6 Summary: Eriophyoidea and Nematalycidae form a clade ............................4 Chapter 7 Summary: Conclusion ..................................................................................5 Chapter 2: A new genus and species ................................................................................6 Introduction .................................................................................................................6 viii Materials and methods .................................................................................................7 Description ................................................................................................................ 11 Material examined ..................................................................................................... 23 Type material and depositor ......................................................................................