Wilfried Westheide

Günter Purschke

Markus Böggemann

Andreas Schmidt-Rhaesa

This book is the third volume in a series of 4 volumes in the Handbook of Zoology series treating morphology, anatomy, reproduction, development, ecology, phylogeny, systematics and taxonomy of polychaetous Annelida. It is devoted to the remaining Sedentaria and the first branches of Errantia. These sedentary polychaetes are Terebellida and Arenicolida, all of which are tube-dwelling and deposit feeders. The tubes may be simple burrows stabilized by mucus or the tubes are highly sophisticated often really aesthetic structures build-up of sediment grains glued together by their secretion. Although the former possess anterior appendages used for collecting food particles, these are likely not modified palps rather than a new acquisition. Many of these species are adapted to occur within environments characterized by low oxygen supply and so many members of these taxa possess elaborated branchiae, usually positioned on a number of anterior body segments except for Maldanidae which look like bamboo sticks and thus earned their common name bamboo worms. Members of Arenicolida and Maldanida may occur in high abundance and as such they create biogenically graded sediment beds. The Errantia part starts with Myzostomida, a group of symbiotic animals associated with echinoderms which have been variously placed within the tree of life. As such they show numerous adaptations to this specific mode of life. The next group discussed within Errantia is Protodrilida, a taxon comprising four families of the former archiannelids which belong to the interstitial fauna. Most likely they evolved by miniaturization from larger ancestors. In contrast to typical errants they do not possess well-developed parapodia and antennae. This taxon is followed by Eunicida characterized by possession of a specific jaw apparatus situated ventrally in the foregut and associated with specific musculature. Also being a species rich group showing various feeding modes some of the smallest and the largest members belong to this taxon.

Pleistoannelida, Sedentaria III and Errantia I

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.

Pleistoannelida, Errantia II

This book is the second volume in a series of 4 volumes in the Handbook of Zoology series treating morphology, anatomy, reproduction, development, ecology, phylogeny, systematics and taxonomy of polychaetous Annelida. In this volume a comprehensive review of a few more derived higher taxa within Sedentaria are given, namely Sabellida, Opheliida/Capitellida as well as Hrabeiellidae. The former comprise annelids possessing a body divided into two more or less distinct regions or tagmata called thorax and abdomen. Here two groups of families are united, the spioniform and sabelliform polychaetes. Especially Spionidae and Sabellidae are speciose families within this group and represent two of the largest annelid families. These animals live in various types of burrows or tubes and all possess so-called feeding palps. In one group these appendages are differentiated as grooved feeding palps, whereas in the other they may form highly elaborated circular tentacular crowns comprising a number of radioles mostly giving off numerous filamentous pinnulae. Often additionally colourful, the latter are also received the common names "feather-duster worms", "flowers of the sea", "Christmas-tree worms". Opheliida/Capitellida including five families of truly worm-like annelids without appendages represents the contrary. Their members burrow in soft bottom substrates and may be classified as non-selective deposit feeders. Molecular phylogenetic analyses have shown that Echiura or spoon worms, formerly regarded to represent a separate phylum, are members of this group. Last not least Hrabeiellidae is one out of only two families of oligochaete-like terrestrial polychaetes and for this reason received strong scientific interest.

Markus Böggemann

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