<i>Potamotrygon</i> spp.: Elasmobranchs with Low Urea Content
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- Thomas B. Thorson
- Department of Zoology and Physiology, University of Nebraska, Lincoln
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- C. Michael Cowan
- Department of Zoology and Physiology, University of Nebraska, Lincoln
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- Donald E. Watson
- Department of Zoology and Physiology, University of Nebraska, Lincoln
Abstract
<jats:p> All previously reported species of Chondrichthyes, from both marine and fresh water, have contained urea at concentrations ranging from about 300 to 1300 milligrams of urea nitrogen per 100 milliliters of fluid. Body fluids from two species of <jats:italic>Potamotrygon</jats:italic> , permanent residents of the Amazon basin, contained only 2 to 3 milligrams of urea nitrogen per 100 milliliters. Although they have abandoned the retention of urea exhibited by other chondrichthyans, the extent to which they have lost the mechanisms of retaining and tolerating urea in a hypertonic medium has not been determined. </jats:p>
Journal
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- Science
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Science 158 (3799), 375-377, 1967-10-20
American Association for the Advancement of Science (AAAS)
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Keywords
Details 詳細情報について
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- CRID
- 1362544418303364096
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- NII Article ID
- 30020491780
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- ISSN
- 10959203
- 00368075
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- Data Source
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- Crossref
- CiNii Articles