The Relationships of Megaoryzomys Curioi, an Extinct Cricetine Rodent (Muroidea, Muridae) from the Galápagos Islands, Ecuador
The Relationships of Megaoryzomys Curioi, an Extinct Cricetine Rodent (Muroidea, Muridae) from the Galápagos Islands, Ecuador

Author: David W. Steadman

Publisher:

Published: 1982

Total Pages: 32

ISBN-13:

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Megaoryzomys curioi is a thomasomyine, not an oryzomyine as previously believed. This rodent was originally described, from three bony fragments found in a cave on Isla Santa Cruz, Galápagos, as a new species of the Antillean oryzomyine genus Megalomys. The genus Megaoryzomys was named recently for this species, based on new material from Isla Santa Cruz. Our study of additional material indicates that Megaoryzomys curioi is not closely related to Oryzomys but is most similar to large species of Thomasomys, a genus confined to mainland South America. The Galápagos have been colonized by cricetine rodents at least three times, once by a thomasomyine and twice by oryzomyines. Of these colonists, Megaoryzomys curioi is the most divergent from mainland relatives and thus is probably derived from the earliest immigrant. Although the time of extinction of Megaoryzomys curioi has not been determined, and it has never been recorded from life, it probably survived into historic time.

Galápagos Marine Invertebrates
Galápagos Marine Invertebrates

Author: Matthew J. James

Publisher: Springer Science & Business Media

Published: 2013-11-22

Total Pages: 466

ISBN-13: 1489906460

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Marine Invertebrate Evolution in the Galapagos Islands MATTHEW J. JAMES 1. Perspective of This Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. Directions for Future Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Plan of This Volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Perspective of This Volume Charles Darwin brought the Galapagos Islands to the attention of zoologists, botanists, and geologists following the six-week visit of H. M. S. Beagle to the islands in 1835. Since then published research on the biota of the islands, partic ularly in multiauthored volumes, has focused on terrestrial plants and animals. The present volume is designed specifically to provide a summary of work on the marine invertebrate fauna. One deviation from that objective was the inclusion of a chapter on land snails, which proved to be a good choice because the phylum Mollusca is now covered more thoroughly in this volume than in any single previous scholarly work on the Galapagos. The academic bottom line with this book is to elucidate the evolutionary responses of shallow water, benthic marine invertebrates to the unique set of insular conditions that exist in the Galapagos Islands. The route taken to that objective has many paths including taxonomic revision, determining biogeo graphic affinities, and examining the ecological requirements of species. The information presented here is for some groups from the islands the first stage in a thorough process that can eventually lead to an understanding of the phylogenetic relationships of these species.

American Megafaunal Extinctions at the End of the Pleistocene
American Megafaunal Extinctions at the End of the Pleistocene

Author: Gary Haynes

Publisher: Springer Science & Business Media

Published: 2008-12-23

Total Pages: 200

ISBN-13: 1402087934

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The volume contains summaries of facts, theories, and unsolved problems pertaining to the unexplained extinction of dozens of genera of mostly large terrestrial mammals, which occurred ca. 13,000 calendar years ago in North America and about 1,000 years later in South America. Another equally mysterious wave of extinctions affected large Caribbean islands around 5,000 years ago. The coupling of these extinctions with the earliest appearance of human beings has led to the suggestion that foraging humans are to blame, although major climatic shifts were also taking place in the Americas during some of the extinctions. The last published volume with similar (but not identical) themes -- Extinctions in Near Time -- appeared in 1999; since then a great deal of innovative, exciting new research has been done but has not yet been compiled and summarized. Different chapters in this volume provide in-depth resumés of the chronology of the extinctions in North and South America, the possible insights into animal ecology provided by studies of stable isotopes and anatomical/physiological characteristics such as growth increments in mammoth and mastodont tusks, the clues from taphonomic research about large-mammal biology, the applications of dating methods to the extinctions debate, and archeological controversies concerning human hunting of large mammals.

Evolution of Island Mammals
Evolution of Island Mammals

Author: Alexandra van der Geer

Publisher: John Wiley & Sons

Published: 2011-02-14

Total Pages: 512

ISBN-13: 1444391283

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Evolution on islands differs in a number of important ways from evolution on mainland areas. Over millions of years of isolation, exceptional and sometimes bizarre mammals evolved on islands, such as pig-sized elephants and hippos, giant rats and gorilla-sized lemurs that would have been formidable to their mainland ancestors. This timely and innovative book is the first to offer a much-needed synthesis of recent advances in the exciting field of the evolution and extinction of fossil insular placental mammals. It provides a comprehensive overview of current knowledge on fossil island mammals worldwide, ranging from the Oligocene to the onset of the Holocene. The book addresses evolutionary processes and key aspects of insular mammal biology, exemplified by a variety of fossil species. The authors discuss the human factor in past extinction events and loss of insular biodiversity. This accessible and richly illustrated textbook is written for graduate level students and professional researchers in evolutionary biology, palaeontology, biogeography, zoology, and ecology.