Download or read book Revision of Sternaspis Otto 1821 Polychaeta Sternaspidae written by Kelly Sendall and published by PenSoft Publishers LTD. This book was released on 2013-04-08 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Echinoderm Fauna of the Azores NE Atlantic Ocean written by author 1 and published by . This book was released on 2019 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Abstract: In more than 150 years of research in the waters surrounding the Azores, several publications on the fauna of echinoderms of the archipelago have been produced, in the form of papers, notes, reports, reviews, and monographs. This work attempts to summarize the present knowledge on this marine group in the Azorean exclusive economic zone (i.e., waters within 200 nautical miles of the archipelago's shores). A short review of the history of the species' taxonomy is given, with key references, geographical distribution, ecology, additional notes and, when possible, figures. We herein report 172 species of echinoderms (6 crinoids, 55 ophiuroids, 45 asteroids, 36 holothurians, and 30 echinoids) from the Azores Archipelago, most of them inhabiting deep waters (>200 m). Only 29 shallow-water species were recorded locally (≤50 m depth). In general, the echinoderm species present in the Azores are characterized by a wide geographical distribution in the Atlantic Ocean. Only nine taxa (all deep-water species, >840 m) appear to be restricted to the Azorean waters. Overall, the knowledge of the echinoderm fauna of the Azores is out-dated, with many species last collected in the archipelago over 100 years ago. A recent interest in the Azorean Mid-Atlantic waters has brought oceanographic cruises back to the archipelago, thus providing new opportunities for the renewal of 150 years of echinoderm studies in the area. Keywords: Echinodermata"--Page 3.
Download or read book The Families and Genera of Marine Gammaridean Amphipoda written by Jerry Laurens Barnard and published by . This book was released on 1969 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keys and diagnoses, with illustrations, to the families and genera of marine gammaridean Amphipoda are presented here in the form of a handbook. Since 1906 the number of families has been increased by 25 percent, the number of genera by 200 percent and the number of species by nearly 200 percent.
Download or read book International Catalogue of Scientific Literature written by and published by . This book was released on 1906 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book R sultats des campagnes MUSORSTOM written by Jacques Forest and published by French National Museum Natural History. This book was released on 1981 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Tropical Deep-Sea Benthos, a continuation of Résultats des Campagnes MUSORSTOM, is a series dedicated to the inventory and description of the deep-sea fauna of the world, with special emphasis on the most extensive, yet remote and least explored, region -- the Indo-West Pacific. The comprehensive series of marine expeditions undertaken by the French Muséum national d'Histoire naturelle and the Institut de Recherche pour le Développement (IRD) continue to collect many new, strange and sometimes colourful crustaceans."--
Download or read book Reproductive Strategies and Developmental Patterns in Annelids written by Adriaan W.C. Dorresteijn and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fascination of the Annelida to scientists lies in the beauty of their structures and the functionality of their body plan, the tremendous adaptive radiation which has made it possible for these animals to colonize almost all marine, limnic and terrestrial biotopes. In doing so they have evolved a great variety of life forms, and their reproduction and development are correspondingly diverse, with many modes and patterns unique in the animal kingdom. In this special volume recent progress in this broad research area is presented by 26 specialists, in general through surveys or treatments of selected examples. Some of them review important annelid taxa such as the Nereididae, Syllidae, Spionidae, Cirratulidae, Clitellata, and Pogonophora; others analyse reproductive and developmental structures and phenomena in annelids, e.g. segmental organs, sex pheromones, oogenesis, mating systems, sperm types, life cycles, larval settlement, cleavage and symmetry of embryos, or discuss controversial approaches to annelid systematics. The book will be of interest to all zoologists who work with annelids as well as to embryologists and other researchers in reproductive biology.
Download or read book Medusae written by Paul Lassenius Kramp and published by . This book was released on 1948 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantifying Holocene Sea level Change Using Intertidal Foraminifera written by Benjamin P. Horton and published by . This book was released on 2006 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chromosome Structure and Aberrations written by Tariq Ahmad Bhat and published by Springer. This book was released on 2017-02-08 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a compilation of various chapters contributed by a group of leading researchers from different countries and covering up to date information based on published reports and personal experience of authors in the field of cytogenetics. Beginning with the introduction of chromosome, the subsequent chapters on organization of genetic material, karyotype evolution, structural and numerical variations in chromosomes, B-chromosomes and chromosomal aberrations provide an in-depth knowledge and easy understanding of the subject matter. A special feature of the book is the inclusion of a series of chapters on various types of chromosomal aberrations and their impact on breeding behaviour and crop improvement. The possible mechanism, their consequences and role in genetic analysis has been emphasized in these chapters. A few chapters have also been dedicated on various techniques routinely used in the laboratory by students and researchers. Each chapter ends with an extensive bibliography so that the students and researchers may find it relevant to consult more literature on the subject than a book of this size can offer. The book is intended to fulfill the needs of undergraduate and post graduate students of botany, zoology and agriculture besides, teachers and researchers engaged in the field of genetics, cytogenetics, and molecular genetics. In general the readers will find each chapter of the book informative and easy to understand.
Download or read book The Marine Fauna of New Zealand written by Helen E. S. Clark and published by . This book was released on 2000 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reef and Shore Fauna of Hawaii written by Dennis M. Devaney and published by . This book was released on 1987 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt:
