Richard C. Brusca, Ph.D., University of Arizona, is Executive Director Emeritus of the Arizona-Sonora Desert Museum and a Research Scientist in the Department of Ecology and Evolutionary Biology at the University of Arizona. Dr. Brusca is the author of over 200 research publications and 15 books, and the recipient of more than 100 research grants from the National Science Foundation, NOAA, and the National Geographic Society, and many others. He is a Fellow of the American Association for the Advancement of Science, the Linnean Society of London, and the California Academy of Sciences. His research interests include invertebrate zoology, the natural history of the Sonoran Desert and Gulf of California, and ecology of Arizona's Madrean Sky Islands.

Gonzalo Giribet, Ph.D., University of Barcelona, is Alexander Agassiz Professor of Zoology, Curator of Invertebrates and Director of the Museum of Comparative Zoology, Harvard, and a Professor in the Department of Organismic and Evolutionary Biology. In addition, he holds an Doctor Honoris Causa from the University of Copenhagen, and he an Honorary Research Fellow at The Natural History Museum, London, a Fellow of the California Academy of Sciences, and a 2016 Fellow of the John Simon Guggenheim Memorial Foundation. He has published more than 400 scientific articles and book chapters, and has named more than 100 new species, genera, and families of invertebrates. His research is broadly interested in the origins and maintenance of animal diversity, which he explores through studying the evolution, systematics, and biogeography of invertebrate animals.

Wendy Moore, Ph.D., University of Arizona, is Associate Professor in the Department of Entomology at the University of Arizona and Curator of the University of Arizona Insect Collection. Her long-term research interest is the evolution of diversity, particularly of invertebrates and especially of insects. She is a systematist who uses molecular-based phylogenetics to understand the evolution of morphology and how biotic, climatic, and tectonic events may have influenced the timing and patterns of diversification. She is also committed to natural history collections care and enhancement, and the use of bioinformatics to make collections-based data widely available to diverse user communities.

• Chapter 1


• Introduction


• Keeping Track of Life


• Prokaryotes and Eukaryotes


• Where Did Invertebrates Come From?


• Where Do Invertebrates Live?


• Changing Views of Invertebrate Phylogeny


• A Final Introductory Message to the Reader


• Chapter 2


• Systematics, Phylogeny, and Classification


• Phylogeny, Monophyly, Paraphyly, and Polyphyly


• Homology


• Apomorphy and Plesiomorphy


• Challenges of Phylogenetic Inference


• Constructing Phylogenies


• Biological Classification


• Nomenclature


• Chapter 3


• Introduction to the Animal Kingdom: Animal Architecture and Body Plans


• Body Symmetry


• Cellularity, Body Size, Germ Layers, and Body Cavities


• Locomotion and Support


• Cilia and Flagella


• Feeding and Digestion


• Excretion and Osmoregulation


• Circulation and Gas Exchange


• Nervous Systems and Sense Organs


• Bioluminescence


• Nervous Systems and Body Plans


• Hormones and Pheromones


• Reproduction


• Chapter 4


• Introduction to the Animal Kingdom: Development, Life Histories, and Origin


• Evolutionary Developmental Biology: Evo-Devo


• Eggs and Embryos


• Life Cycles: Sequences and Strategies


• The Relationships Between Ontogeny and Phylogeny


• The Origin of the Metazoa


• Chapter 5


• Phylum Porifera: The Sponges


• Taxonomic History and Classification


• The Poriferan Body Plan


• Some Additional Aspects of Sponge Biology


• Poriferan Phylogeny


• Chapter 6


• Two Enigmatic Phyla: Placozoa and Ctenophora (The Comb Jellies)


• Phylum Ctenophora


• Taxonomic History and Classification


• The Ctenophoran Body Plan


• Ctenophoran Phylogeny


• Chapter 7


• Phylum Cnidaria: Anemones, Corals, Jellyfish, and Their Kin


• Taxonomic History and Classification


• The Cnidarian Body Plan


• Cnidarian Evolutionary History


• Chapter 8


• A Brief introduction to the Bilateria and Its Major Clades


• Deuterostomes and Protostomes


• Chapter 9


• Phylum Xenacoelomorpha. Basal Bilaterians


• The Basal Bilaterian


• Phylum Xenacoelomorpha


• Subphylum Acoelomorpha


• Class Acoela


• The Acoel Body Plan


• Class Nemertodermatida


• The Nemertodermatid Body Plan


• Subphylum Xenoturbellida


• The Xenoturbellid Body Plan


• Chapter 10


• Protostomia, Spiralia, and the Phylum Dicyemida


• Spiralia and Ecdysozoa


• The Phylum Dicyemida (= Rhombozoa)


• Anatomy and Biology of Dicyemidans


• Life Cycles


• Chapter 11


• Gnathifera. The Phyla Gnathostomulida, Rotifera (including Acanthocephala), Micrognathozoa, and Chaetognatha


• Phylum Gnathostomulida: The Gnathostomulids


• The Gnathostomulid Body Plan


• Phylum Rotifera: The Free-Living Rotifers


• The Rotifer Body Plan


• Body Cavity, Support, and Locomotion


• Nervous System and Sense Organs


• Reproduction and Development


• Phylum Rotifera, Subclass Acanthocephala: The Acanthocephalans


• The Acanthocephalan Body Plan


• Phylum Micrognathozoa: The Micrognathozoans


• The Micrognathozoan Body Plan


• Phylum Chaetognatha


• Chaetognath Classification


• The Chaetognath Body Plan


• Reproduction and Development


• Chapter 12


• Platytrochozoa and Two Enigmatic Phyla: Entoprocta and Cycliophora


• Phylum Entoprocta: The Entoprocts


• The Entoproct Body Plan


• Phylum Cycliophora: The Cycliophorans


• Chapter 13


• Introduction to the Lophotrochozoa, and the Phylum Mollusca


• The Lophotrochoza


• Phylum Mollusca


• Taxonomic History and Classification


• The Molluscan Body Plan


• Molluscan Evolution and Phylogeny


• Chapter 14


• Phylum Nemertea: The Ribbon Worms


• Taxonomic History and Classification


• The Nemertean Body Plan


• Nemertean Phylogeny


• Chapter 15


• Phylum Annelida. The Segmented (and Some Unsegmented) Worms


• Taxonomic History and Classification


• The Annelid Body Plan


• Sipuncula: The Peanut Worms


• Sipunculan Classification


• The Sipunculan Body Plan


• Thalassematidae: The Spoon Worms


• Siboglinidae: Vent Worms and Their Kin


• Siboglinid Taxonomic History


• The Siboglinid Body Plan


• Hirudinea: Leeches and Their Relatives


• The Hirudinean Body Plan


• Orthonectida: Extremely Simplified Annelids


• Annelid Phylogeny


• Chapter 16


• The Lophophorata: Phyla Phoronida, Bryozoa, and Brachiopoda


• Taxonomic History of the Lophophorates


• The Lophophorate Body Plan


• Phylum Phoronida: The Phoronids


• The Phoronid Body Plan


• Phylum Bryozoa: The Moss Animals


• The Bryozoan Body Plan


• Phylum Brachiopoda: The Lamp Shells


• The Brachiopod Body Plan


• Chapter 17


• Rouphozoa: The Phyla Platyhelminthes (Flatworms) and Gastrotricha (Hairy-Bellied Worms)


• Introduction to Rouphozoa


• The Phylum Platyhelminthes (Flatworms)


• Taxonomic History and Classification


• The Platyhelminth Body Plan


• Platyhelminth Phylogeny


• Phylum Gastrotricha: The Gastrotrichs, or Hairy-Bellied Worms


• The Gastrotrich Body Plan


• Reproduction and Development


• Chapter 18


• Introduction to Ecdysozoa: Scalidophora (Phyla Kinorhyncha, Priapula, Loricifera)


• Introduction to Ecdysozoa


• The Scalidophora


• Phylum Kinorhyncha: The Kinorhynchs, or Mud Dragons


• The Kinorhynch Body Plan


• Phylum Priapula: The Priapulans, or Penis Worms


• Priapulan Body Plan


• Nervous System and Sense Organs


• Phylum Loricifera: The Loriciferans


• Chapter 19


• Nematoida: Phyla Nematoda and Nematomorpha


• Phylum Nematoda: Roundworms


• Nematode Classification


• The Nematode Body Plan


• Life Cycles of Some Parasitic Nematodes


• Phylum Nematomorpha: Horsehair Worms and Their Kin


• The Nematomorph Body Plan


• Chapter 20


• Panarthropoda and the Emergence of the Arthropods. Tardigrades, Onychophorans, and the Arthropod Body Plan


• Phylum Tardigrada


• The Tardigrade Body Plan


• Phylum Onychophora


• The Onychophoran Body Plan


• An Introduction to the Phylum Arthropoda


• The Arthropod Body Plan and Arthropodization


• The Evolution of Arthropods


• Chapter 21


• Phylum Arthropoda. Subphylum Crustacea: Crabs, Shrimps, and Their Kin


• Classification of the Crustacea


• Synopses of Crustacean Taxa


• The Crustacean Body Plan


• Crustacean Phylogeny


• Chapter 22


• Phylum Arthropoda. Hexapoda: Insects and Their Kin


• The Hexapod Body Plan


• Hexapod Evolution


• Chapter 23


• Phylum Arthropoda. Subphylum Myriapoda: Centipedes, Millipedes, and Their Kin


• Myriapod Classification


• The Myriapod Body Plan


• Myriapod Phylogeny


• Chapter 24


• Phylum Arthropoda. The Chelicerata


• Synopses of Living Chelicerate Groups*


• The Euchelicerate Body Plan


• The Class Pycnogonida


• The Pycnogonid Body Plan


• Chelicerate Phylogeny


• Chapter 25


• Introduction to Deuterostomia, and the Phylum Hemichordata


• Introduction to the Deuterostomia


• Phylum Hemichordata: Acorn Worms and Pterobranchs


• The Hemichordate Body Plan


• Class...