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Polychaetes are very common marine worms belonging to the Annelid family that are of interest to marine biologists and invertebrate zoologists. The book presents an understanding of the biology of this group with many illustrations.
Annelida, mainly consisting of marine Polychaeta and in faunal and partly parasitic Clitellata, is one the most significant metazoan taxa. Its more than 20.000 described species invade nearly all habitats and play a central role in marine benthic systems as well as in terrestrial soil communities. Annelids include all soft-bodied segmented worm-like organisms and have been recognized as a separate "phylum" for almost 200 years. Recently, evidence has been accumulated which shows that some of the groups formerly regarded as independent "phyla" such as Pogonophora (now recognized as Siboglinidae), Echiura, Myzostomida and perhaps Sipuncula, are most probably nothing else than greatly modified Annelida. The extreme morphological diversity found especially in Polychaeta displays the plasticity of a simple segmented organisation that basically is nothing else but a serial repetition of identical units. Thus, annelids are highly important to our understanding of fundamental questions about morphological and adaptive diversity, as well as clarifying evolutionary changes and phylogenetic relationships. The book aims to summarize our knowledge on Polychaetes polychaetes and their allies and gives an overview of recent advances gained by studies that employed conventional and modern methods plus, increasingly and importantly, the use of molecular markers and computer-assisted kinship analyses. It also reflects the state of art in polychaete sciences and presents new questions and controversies. As such it will significantly influence the direction of research on Polychaeta and their related taxa.
A comprehensive account of Polychaetes in Australia. Based on nearly 2400 references, the authors reveal the wealth of diversity in the largely unknown world of these worm groups, in terms of their morphology, behaviour, reproduction and significance in marine ecosystems.
Annelids offer a diversity of experimentally accessible features making them a rich experimental subject across the biological sciences, including evolutionary development, neurosciences and stem cell research. This volume introduces the Annelids and their utility in evolutionary developmental biology, neurobiology, and environmental/ecological studies, including extreme environments. The book demonstrates the variety of fields in which Annelids are already proving to be a useful experimental system. Describing the utility of Annelids as a research model, this book is an invaluable resource for all researchers in the field.
The global trade of aquatic organisms for home and public aquariums, along with associated equipment and accessories, has become a multi-billion dollar industry. Aquaculture of marine ornamental species, still in its infancy, is recognized as a viable alternative to wild collection as it can supplement or replace the supply of wild caught specimens and potentially help recover natural populations through restocking. This book collects into a single work the most up-to-date information currently available on the aquaculture of marine ornamental species. It includes the contributions of more than 50 leading scientists and experts on different topics relevant for the aquaculture of the most emblematic groups of organisms traded for reef aquariums. From clownfish, to angelfish, tangs and seahorses, as well as corals, anemones, shrimps, giant clams and several other reef organisms, all issues related with the husbandry, breeding, and trade are addressed, with explanatory schemes and illustrations being used to help in understanding the most complex topics addressed. Marine Ornamental Species Aquaculture is a key reference for scientists and academics in research institutes and universities, public and private aquaria, as well as for hobbyists. Entrepreneurs will also find this book an important resource, as the culture of marine ornamental species is analyzed from a business oriented perspective, highlighting the risks and opportunities of commercial scale aquaculture of marine ornamentals.
This book is a concise informative elucidation of all aspects of reproduction and development in annelids covering from arenicola to tubifex. Annelids flourish between 4,900 m depth to 2,000 m altitude; some of them occur in unusual habitats like hydrothermal vents and subterranean aquatic system (stigobionts). A few have no gut and acquire adequate nutrients through osmotrophism and/or engaging symbiotic microbes. In the absence of exoskeleton to escape predation, the 17,000 speciose annelids have explored bewildering modes of reproduction; not surprisingly, 42–47% of them are brooders. With 13,000 species, polychaetes are gonochores but some 207 species of them are hermaphrodites. Clitellates are all hermaphrodites; of them, 76 species are parthenogens, of which 56 are earthworms. Regenerative potency of annelids ranges from an organ to an entire worm from a single ‘seminal’ segment. The head, tail and both together can be regenerated 21, 42 and 20 times, respectively. However, the potency is limited to ~1% of polychaetes and Heterogamatic sex determination is reported to occur only in six polychaete species, although karyotype is known for 83 annelid species. In temperate polychaetes, a dozen neuroendocrines, arising mostly from the ‘brain’ regulates reproductive cycle. A complete chapter devoted to vermiculture, (i) recognizes the fast-growing candidate species, (ii) distinguishes 'layers' from 'brooders', (iii) indicates that the harvest of oligochaetes may reduce the input of nitrogenous fertilizer in the ricefield, and (iv) explores the scope for increasing wealth from waste.