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Each plate accompanied by guard sheet with descriptive letterpress.
This book is the fourth in a series of 4 volumes in the Handbook of Zoology series about morphology, anatomy, reproduction, development, ecology, phylogeny and systematics of Annelida. It covers the most typical polychaetes, Phyllodocida, together with certain smaller taxa placed incertae sedis. This volume completes the polychaetous Annelida. Phyllodocida are often vagile, possess well-developed parapodia. Due to their broad and flat cirri these parapodia look like leaves in some taxa and leading to the name of the entire group. Many of its members are macrophagous and often predators. Accordingly most species possess elaborate sense structures such as sensory palps, antennae, eyes and nuchal organs. In certain species the eyes comprise thousands of photoreceptor cells and lenses most likely allowing forming true images. Phyllodocida typically possess an axial muscular pharynx called proboscis functioning as a kind of suction pipe allowing them to swallow and ingest their prey or other food. This pharynx may be armed with cuticular jaws and some species even possess venom glands. The probably most popular and important polychaete model organism, Platynereis dumerilii, belongs to this interesting group. Phyllodocida fall into two to three higher clades comprising about 25 families which represent more than one fourth of the polychaete diversity. One of these families, Syllidae, comprises about 700 valid species of mainly small size and may, therefore, represent one of the most complex and somehow difficult polychaete families on Earth.
The peanut-shaped sternaspid polychaetes have been known since 1760 when Plancus named them as Mentula cucurbitacea marina. Sternaspids are common and abundant in soft bottoms. Some authors suggested that only one species should be recognized, whereas others regard a few species very widely distributed and variable depths. Delineating species was problematic; the ventro-caudal shield was disregarded or barely used for identifying species. In this contribution the ventral shield is evaluated and its diagnostic potential is confirmed. The revision of Sternaspis is based upon type or topotype materials. Sternaspid body, introvert hooks and shield show three distinct patterns: two genera have 7 abdominal segments and tapered introvert hooks, and one genus has 8 abdominal segments and spatulate introvert hooks. The ventro-caudal shield has 3 different patterns: stiff with ribs, and sometimes concentric lines, stiff with feebly-defined ribs but no concentric lines, and soft with firmly adhered sediment particles. Sternaspis is restricted to include species with 7 abdominal segments, falcate introvert hooks, and stiff shields, often exhibiting radial ribs, concentric lines or both. Two new genera incorporate the remaining species: Caulleryaspis has falcate introvert hooks, 7 abdominal segments, and soft shields with sediment particles firmly adhered on them. Petersenaspis has spatulate introvert hooks, 8 abdominal segments, and stiff shields with poorly-defined ribs but no concentric line. The geographic range of most species is smaller than previously indicated. Keys to genera and to all species are also included.
Annelids (the segmented worms) exist in a remarkably diverse range of mostly marine but also freshwater and terrestrial habitats, varying greatly in size and form. Annelida provides a fully updated and expanded taxonomic reference work which broadens the scope of the classic Polychaetes (OUP, 2001) to encompass wider groups including Clitellata (comprising more than a third of total annelid diversity), Sipuncula, and Thalassematidae (formerly Echiura). It reflects the enormous amount of research on these organisms that has burgeoned since the millennium, principally due to their use as model organisms to address wider and more general evolutionary and ecological questions. Beginning with a clear introduction to the phylum and an outline of annelid taxonomy, this authoritative text describes their collection, the methods to ensure their optimal preservation, and an overview of anatomy with its relevant terminology. The core of the work comprises 77 fully up-to-date taxonomic chapters, informed by anatomy and the latest molecular phylogenomic evidence and carefully organised based on a new, robust phylogenetic hypothesis. Lavishly illustrated throughout with hundreds of previously unpublished high-resolution colour images and SEM micrographs, the sheer beauty and diversity of the annelids is nowhere better presented. Annelida is the definitive reference work for annelid biologists, whilst being of interest to a broader audience of invertebrate zoologists, systematists, and organismal biologists.