The Evolutionary History Of Nematodes

Nematodes are one of the most abundant groups of invertebrates on the face of the earth. Their numbers are estimated to range from 1000 per cm2 in the sand-covered hydrogen sulphide ‘black zone’ beneath the ocean floors to 1.2 billion in a single hectare of soil. Estimates for their species diversity range from 100 000 to 10 million. The past history of nematodes is a mystery, since very few fossils have been discovered. This book establishes a solid base in palaeonematology with descriptions of 66 new fossil species and accounts of all previous fossil and subfossil nematodes from sedimentary deposits, coprolites, amber and mummies. It shows how nematode fossils can be used to establish lineages at various locations and time periods in the earth’s history and when nematodes entered into symbiotic and parasitic associations with plants and animals.

By joining phylogenetics and evolutionary ecology, this book explores the patterns of parasite diversity while revealing diversification processes.

This edited volume on the nematode model Pristionchus pacificus describes an integrative approach to evolutionary biology. It aims for a merger of evolutionary and comparative biology with mechanistic approaches based on genetics and molecular biology. Insight into the function of biological systems obtained from laboratory studies when complemented with ecology, natural variation and natural history of an organism, can provide detailed knowledge of the proximate and ultimate causations of species. Ralf J. Sommer developed P. pacificus as model system for integrative evolutionary biology with case studies in evo-devo and population genetics on La Réunion Island. Similarly, ecological interactions with scarab beetles revealed examples for the evolution of novelty at the morphological and behavioural level and their underlying molecular mechanisms. Contributors include Paul W. Sternberg, Ralf J. Sommer, Jagan Srinivasan, Christian Rödelsperger, Frank C. Schroeder, Robin M. Giblin-Davis, Natsumi Kanzaki, Matthias Herrmann, Angela McGaughran, Katy Morgan, Akira Ogawa, Federico D. Brown, Ray E. Hong, Robbie Rae, Amit Sinha, David Rudel, and Erik J. Ragsdale.

This book is the first complete illustrated compendium of root-knot nematode species from the genus Meloidogyne including 97 species descriptions with comprehensive diagnoses, information on biology, plant-hosts, pathogenicity, symptoms, distribution and biochemical and molecular diagnostics.

This book reviews developments in the molecular biology of plant-nematode interactions that have been driven by the application of genomics tools. The book will be of interest to postgraduate students and to researchers with an interest in plant nematology and/or plant pathology more generally. A series of introductory chapters provide a biological context for the detailed reviews of all areas of plant-nematode interactions that follow and ensure that the bulk of the book is accessible to the non-specialist. A final section aims to show how these fundamental studies have provided outputs of practical relevance.

This book contains 22 chapters on various aspects of freshwater nematode ecology and taxonomy. Subjects covered include the techniques for processing freshwater nematodes, the composition and distribution of free living freshwater nematodes, their abundance, biomass and diversity, the production of freshwater nematodes, their feeding ecology, patterns in size structure of freshwater nematode communities, different nematode habitats, and computation and application of nematode community indices. It provides descriptions with figures of each taxon at the genus level and above to currently valid genera. For every genus, a complete list of species, with an emphasis on biogeography, is given for primarily freshwater taxa and a list of only those species reported from freshwater bodies is given for the genera that are considered primarily non-freshwater. This book is intended to provide a useful reference to students, beginners and established researchers in the field of freshwater nematology, benthologists, invertebrate biologists, limnologists, ecologists, microbiologists and soil biologists.

The major objective of this book is to highlight the significance of phytonematodes in horticulture. Detailed and latest information on major aspects of phytonematodes associated exclusively with horticultural crops, which is the need of the day, is lacking. Hence, the book has been written mainly with the objective of providing its readers, comprehensive information on the advanced aspects related to phytonematodes associated with horticultural crops. It also provides basic information on plant parasitic nematodes since it is required for a better understanding of advanced topics. Several popular topics, information on which is already available in plenty, have been avoided. Thus, book explicates both the essential fundamental and advanced aspects pertaining to nematodes associated with horticultural crops. The book is conveniently divided into 13 chapters, which cover latest information on the major fundamental and advanced aspects related to phytonematodes including the role of phytonematodes in horticultural industry, phylogenetic and evolutionary concepts in nematodes, major phytonematodes associated with horticultural crops and their diagnostic keys, symptoms caused by phytonematodes and disease diagnosis, nematode population threshold levels, crop loss assessment, nematode diseases of horticultural crops and their management, nematode disease complexes, genetics of nematode parasitism, important nematological techniques and nematodes of quarantine importance. An exclusive chapter on novel methods of nematode management has been included mainly to provide the information on the latest molecules and novel modes of managing nematodes attacking horticultural crops. Routine nematode management aspects, information on which is already available, have not been discussed; instead, this topic reflects the changing scenario of future nematode management. Hence, this book can serve as a friendly guide to meet the requirements of the students, teachers and researchers interested in these ‘hidden enemies’ of the grower, apart from the research and extension personnel working under Public organizations, officials of State departments of Horticulture, Forestry, field workers and all those concerned and working with plant parasitic nematodes. Appropriate diagrams, convincing tables and suitable graphs/illustrations have been furnished at right places. A complete bibliography has also been included.

General principles for the phylogenetic systematic of nematodes; Phylogenetic systematics: problems, achievements and its application to the nematoda; Nematoda higher classification as influenced by species and family concepts; The use of the subspecies and the superspecies categories in nematode taxonomy; Cytogenetic aspects of nematode evolution; The use of the female reproductive system in nematode systematics; Observations on spermatozoa in aquatic nematodes; Scanning electron microscopy as a tool in nematode taxonomy; Evolution of plant parasitism in nematodes; Tylenchidae: morphological diversity in a natural, evolutionary group; Phylogeny, historical biogeography and the species concept in soil nematodes; Problems of species delimitation in the genus Xiphinema, with special reference to monosexual species; Taxonomic problems in long-tailed dorylaims; Enzyme polymorphism and the concept of parthenogenetic species exemplified by Meloidogyne; Problems in the classification of Meloidogyne reproducing by mitotic parthenogenesis; Diversity of selected taxa of Globodera and Heterodera and their interspecific and intergeneric hybrids; Three approaches to the status of a species complex, with a revision of some species of Globodera (Nematoda: Heteroderidae); The potential of some immunochemical and biochemical approaches to the taxonomy of potato cyst-nematodes; Phylogenetic relationships in the mermithidae (Nematoda) based on traditional and physiological evidence; Morphology of the genital cone in the nematode family trichostrongylidae and its value as a taxonomic character; The synlophe and species determination of Trichostrongyloidea; Polymorphism in the Trichostrongylidae; Observations on the systematics of ascaridoid nematodes; The systematics of ascaridoid nematodes - a current assessment; Species recognition in human filaroids; The species problem in Trichinella; Taxonomic problems in capillariid nematodes parasitic in cold-blooded vertebrates.

Cheap and plentiful genome sequence data is transforming biology, and will surely transform systematics. This volume explores how.

Volume 8 in the series, appearing in two parts, A and B, deals with the systematics of cyst nematodes of the subfamily Heteroderinae. Cyst nematodes are important pathogens causing extensive damage and significant yield loss to many crops in both temperate and tropical regions.