Tiger Shark Mating Scars


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The reproduction and development of sharks, skates, rays and ratfishes


The reproduction and development of sharks, skates, rays and ratfishes

Author: Leo S. Demski

language: en

Publisher: Springer Science & Business Media

Release Date: 2013-06-29


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This volume had its origin in a symposium on the Reproduction and Development of Cartilaginous Fishes that was held at the annual meetings of the American Elasmobranch Society and the American Society of Ichthyologists and Herpetologists in Charleston, South Carolina in 1990. The cartilaginous fishes, class Chondrichthyes, are a large and diverse group of fishes that include approximately 900 to 1100 living species of sharks, skates, rays and ratfishes. Throughout their history, which dates back at least 400 million years, they have been a successful major component of the marine ecosystem. The chondrichthyan fishes occupy a pivotal position in comparative and evolutionary studies of vertebrate reproduction and development. They are the oldest surviving group of jawed vertebrates and they possess both the adult vertebrate Bauplan and the vertebrate program of embryonic development. The major features of the female reproductive system, including its embryonic origin, structure, physiological function, and biochemistry, apparently were established early in vertebrate evolution and are fully developed in chondrichthyan fishes. These features of the female reproductive system have been retained during the evolution of the other classes of vertebrates. Much the same can be said for the male reproductive system. Moreover, viviparity, placental nourishment of developing embryos, and the hormonal regulation of these events made an initial appearance in this group. The 22 articles presented in this volume bring together a wide variety of complementary research by investigators from seven countries, allowing us to broaden the scope and implications of our studies while identifying opportunities for future research. The appearance of a volume on the reproduction and development of cartilaginous fishes is quite opportune. The continued existence of these fishes, which survived the great extinction events of Earth's history, is nowthreatened by overexploitation unless immediate steps for their conservation are undertaken. Knowledge of their reproduction and development not only is an end in itself, but is of critical importance in devising successful conservation and resource management strategies.

The behavior and sensory biology of elasmobranch fishes: an anthology in memory of Donald Richard Nelson


The behavior and sensory biology of elasmobranch fishes: an anthology in memory of Donald Richard Nelson

Author: Timothy C. Tricas

language: en

Publisher: Springer Science & Business Media

Release Date: 2013-06-29


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The elasmobranch fishes include the living sharks, skates and rays that are important members of nearly all marine ecosystems. Their large size, secretive behavior, and wide-ranging habits make them difficult to observe in the field or to maintain in captivity. Consequently, little is known about their natural behavior and how it is mediated by their sensory systems. This volume is dedicated to the scientific contributions and memory of Donald Nelson, a pioneer in the study of shark behavior, sensory biology, and remote instrumentation. The two opening papers review Don Nelson's unique scientific accomplishments and provide insight into his strong bias towards study of animals in the field. These are followed by 14 scientific papers on elasmobranch behavior, sensory biology, and current monitoring technologies. The papers on elasmobranch sensory biology and behavior address questions on hearing, the lateral line, electroreception, the brain, orientation behavior, chemical irritants, feeding, and reproduction. The latter section of the volume presents papers on conventional tagging techniques, ultrasonic telemetry, physiological telemetry, remote monitoring techniques, archival tagging and satellite tagging. The intent of this volume is to familiarize both new and established scientists with the sensory biology and behavior of sharks and rays, and to encourage further behavioral research on these animals in their natural environment.

The Dawn of the Deed


The Dawn of the Deed

Author: John A. Long

language: en

Publisher: University of Chicago Press

Release Date: 2012-10-22


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“[A] deliciously written account of the evolution of sex, in all of its bizarre manifestations” by a noted paleontologist—"Read, blush, and enjoy!” (Jared Diamond, author of Guns, Germs, and Steel). We all know about the birds and the bees, but what about the ancient placoderm fishes and the dinosaurs? In 2008, paleontologist John A. Long and a team of researchers announced their discovery of a 380-million-year-old placoderm fish fossil, known as “the mother fish,” which revealed the earliest known example of internal fertilization. As a result, placoderms are now considered to be the first species to have had intimate sexual reproduction, or sex as we know it—sort of. Inspired by this incredible find, Long began a quest to uncover the evolutionary history of copulation and insemination. In The Dawn of the Deed, he takes readers on a lively tour through the sex lives of ancient fish and the unusual mating habits of arthropods, tortoises, and even a well-endowed Argentine Duck. Long discusses these discoveries alongside what we know about reproductive biology and evolutionary theory, using the fossil record to provide a provocative account of prehistoric sex. The Dawn of the Deed also explores fascinating revelations about animal reproduction, from homosexual penguins to monogamous seahorses to the difficulties of dinosaur romance.